bombus vestalis , the vestal cuckoo bumblebee , is a species of cuckoo bumblebee that lives in most of europe , as well as north africa and western asia .

it is a brood parasite that takes over the nests of other bee species .

its primary host is bombus terrestris ( the buff-tailed bumblebee ) .

after its initial classification as psithyrus vestalis , this bumblebee recently was reclassified into the genus bombus , subgenus psithyrus .

bombus vestalis

specialist bombus vestalis and generalist bombus bohemicus use different odour cues to find their ho . . .
kreuter k , twele r , francke w , ayasse m . specialist bombus vestalis and generalist bombus bohemicus use different odour cues to find their host bombus terrestris .
suppression of ovarian development of bombus terrestris workers by b . terrestris queens , psithyrus vestalis and psithyrus bohemicus females
relative abundance ( median , rel . % ) of the compounds identified in cephalic secretions of bombus vestalis males .
all the sets of contigs and singletons from cotesia vestalis with similarity to or genes .
all the sets of contigs and singletons from cotesia vestalis with similarity to obp genes .
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kreuter k , twele r , francke w , ayasse m : specialist bombus vestalis and generalist bombus bohemicus use different odour cues to find their host bombus terrestris . anim behav . 2010 , 80 : 297 - 302 . 10 . 1016 / j . anbehav . 2010 . 05 . 010 .
are forests potential landscape barriers for foraging bumblebees ? landscape scale experiments with bombus terrestris agg . and bombus pascuorum ( hymenoptera , apidae )
composition of the males ' cephalic secretions of b . vestalis , b . terrestris and b . pascuorum
b . vestalis is very similar to b . bohemicus , though in leicestershire and rutland b . vestalis is much more common . they can be separated by the antennal segments ( clearly needing a good photo to do so ) : - if segment 3 equals the length of segment 5 = b . bohemicus ; and if 3 is shorter than 5 , then it is b . vestalis . b . vestalis parasities bombus terrestis so closely mimics this species and therefore has a darker yellow band on the thorax , wheras b . bohemicus has a paler yellow band to mimic its host species - bombus lucorum .
information flow and regulation of foraging activity in bumble bees ( bombus spp . )
it has been decided to rename the genus of cuckoo bumblebees from psithyrus to bombus .
phylogenetic relationships among bumble bees ( bombus latr . ) : a reappraisal of morphological evidence
the study of the social interactions between host bumblebees and their inquiline species requires rearing them . here we provide a simple method for rearing of cuckoo bumblebees ( bombus subgenus psithyrus ) in the laboratory . two bumblebee cuckoo - host systems are used : bombus ( psithyrus ) vestalis hosted by b . ( bombus ) terrestris and b . ( psithyrus ) sylvestris hosted by b . ( pyrobombus ) pratorum . . . . [ show full abstract ]
cameron sa , hines hm , williams ph . a comprehensive phylogeny of the bumble bees ( bombus )
the role of trail pheromones in host nest recognition of the social parasitic bumblebees bombus bohe . . .
relative abundance ( median , rel . % ) of the compounds identified in the cephalic secretions of the males of bombus terrestris ( n = 5 ) , b . pascuorum ( n = 12 ) and b . vestalis ( n = 5 ) .
bombus franklini frison , 1921 . franklin ' s bumble bee ( hymenoptera : apidae : apinae : bombini )
the name cuckoo bumblebee refers to the fact that these bees are brood parasites in the nests of other bumblebees ( 3 ) . bombus terrestris ( the great earth bumblebee ) is the only known host of bombus vestalis , and the cuckoo’s distribution reflects the predominantly southern distribution of its host in britain ( 4 ) , and presumably also throughout its palaearctic range ( 2 ) .
in behavioural experiments and histological investigations we could demonstrate that the previously widespread generalization that females of the social parasite genus bombus subgenus psithyrus do not possess wax glands is not justified . wax pieces that accumulated on the abdomina of bombus vestalis , b . sylvestris , and b . bohemicus females which were prevented from self - grooming provided the . . . [ show full abstract ]
age - dependent attractivity of males ' sexual pheromones in bombus terrestris ( l . ) [ hymenoptera , apidae ]
a method for year - round rearing of cuckoo bumblebees ( hymenoptera : apoidea : bombus subgenus psithyru . . .
the four species sequenced only for the 16s fragment were resolved in the 16s tree within their expected subgenera . in particular , b . luteipes fell within the pyrobombus clade ( bombus avanus + b . sonani + bombus infrequens + b . parthenius ) ( pp = 0 . 90 ) , attaching to b . infrequens + b . parthenius as an unresolved trichotomy ( pp = 0 . 97 ) ; b . tunicatus attached as sister to bombus terricola ( pp = 0 . 74 ) ; b . coreanus was sister to bombus ashtoni + bombus bohemicus ( pp = 0 . 85 ) ; and b . wilemani was sister to bombus trifasciatus ( pp = 1 . 0 ) .
on the variation of bombus lapidarius l . and its cuckoo , psithyrus rupestris fabr . , with notes on mimetic similarity
inter - tegular span and head width as estimators of fresh and dry body mass in bumblebees ( bombus spp . )
o’connor s , park kj , goulson d . worker drift and egg dumping by queens in wild bombus terrestris colonies .
sramkova a , schulz c , twele r , francke w , ayasse m . fertility signals in the bumblebee bombus terrestris .
species distribution of top hits for the pyrosequencing contigs / singletons from c . vestalis adult female antennae ( n = 17 597 ; 35 . 7 % , blast hits ) .
a monograph of the western hemisphere bumblebees ( hymenoptera : apidae ; bombinae ) . i . the genera bombus and megabombus subgenus bombias
specific distinctness of bombus nevadensis ( cresson ) and b . auricomus ( robertson ) ( hymenoptera : apidae ) − enzyme electrophoretic data
inter - tegular span and head width as estimators of fresh and dry body mass in bumblebees ( bombus spp . ) | springerlink
is in the bumblebee tribe , bombini . it is in the genus bombus , which consists entirely of bumblebees , and the subgenus
takes over the nest of bombus terrestris . the female enters the nest and kills the queen , then laying her own eggs to be reared by the bombus terrestris workers . mated female cuckoo bees hibernate through the winter and emerge in the spring later than their hosts .
van doorn a , heringa j . the ontogeny of a dominance hierarchy in colonies of the bumble bee bombus terrestris ( hymenoptera : apidae )
amsalem e , twele r , francke w , hefetz a . reproductive competition in the bumble - bee bombus terrestris : do workers advertise sterility ?
distinguishing similar species : unlike b . bohemicus , b . vestalis have ( 1 ) short even hair and ( 2 ) golden yellow bands . against other species , males can be distinguished by their genitalia .
distinguishing similar species : unlike b . vestalis , b . bohemicus have ( 1 ) long hair and ( 2 ) lemon - yellow bands . against other species , males can be distinguished by their genitalia .
taxonomic status : a study of the taxon perezi on corsica in comparison with b . vestalis in neighbouring europe by lecocq et al . ( 2014 ) concluded that the taxon perezi is an endemic corsican subspecies .
observations on scent marking by bombus latr . and psithyrus lep . males ( hym . , apidae ) and localization of site of production of the secretion
transcription levels of genes for or1 to 6 were normalized to those of c . vestalis 60s ribosomal protein l10 ( cv _ 000471 ) , and expressed relative to the normalized transcript levels in the body of c . vestalis males . data represent the mean and standard errors ( n = 5 ) . means followed by different small letters are significantly different ( p < 0 . 05 , tukey - kramer hsd test ) .
transcription levels of genes for obp1 to 10 were normalized to those of c . vestalis 60s ribosomal protein l10 ( cv _ 000471 ) , and expressed relative to the normalized transcript levels in the body of c . vestalis males . data represent the mean and standard errors ( n = 5 ) . means followed by different small letters are significantly different ( p < 0 . 05 , tukey - kramer hsd test ) .
common and takes over the nests of bombus lucorum . body lengths , female ( above left ) 19 mm , male ( above right ) 16 mm .
common and takes over the nests of bombus hortorum . body lengths , female ( above left ) 18 mm , male ( above right ) 15 mm .
williams & christian ( 1991 ) planted three 9 m 2 plots of phacelia at rothamsted research experimental farm , hertfordshire , england . seven species of bumblebee , including the long - tongued common carder bee bombus pascuorum , and one cuckoo bumblebee b . [ psithyrus ] vestalis foraged on the phacelia . of observed worker bumblebee visits , 97 % were for nectar , not pollen .
we also tested if the parasite males ' acceptance could be due to a decrease of worker recognition in parasitized colonies . we performed the same experiments on four queenless b . terrestris colonies parasitized by the social parasite b . vestalis . we finally tested whether the presence of parasite males can affect host worker recognition abilities . therefore , we repeated the previous experiment on four queenless parasitized colonies of b . terrestris with emerged b . vestalis males .
common and takes over the nests of bombus pascuorum . body lengths , female ( above ) 18 mm , male , light and dark forms below 15 mm .
bloch g , borst dw , huang zy , robinson ge , hefetz a . effects of social conditions on juvenile hormone mediated reproductive development in bombus terrestris workers .
duchateau mj : agonistic behaviours in colonies of the bumblebee bombus terrestris . j ethol . 1989 , 7 : 141 - 151 . 10 . 1007 / bf02350036 .
inter - and intrasubgeneric relationships of bombus were inferred largely from bayesian analyses , implemented in mrbayes , version 3 . 1 . 2 ( ronquist & huelsenbeck , 2003 ) on an ibm p - series 690 supercomputer operated by the national center for supercomputing applications ( university of illinois at urbana - champaign , champaign , il ) . genes were analysed individually and collectively , each partitioned into exon , intron and gap regions ( when applicable ) to account for variation in evolutionary rates among gene regions . four taxa sequenced only for the 16s fragment ( bombus tunicatus , bombus wilemani , bombus coreanus , and b . luteipes ) were excluded from collective analyses .
alaux c , boutot m , jaisson p , hefetz a . reproductive plasticity in bumblebee workers ( bombus terrestris ) – reversion from fertility to sterility under queen influence .
through competition and pathogen introduction / spillover . bombus ruderatus , a bee previously introduced in 1982 , is also seriously affected . the cause is thought to be the parasite
in order to mate the female must extend her sting so that the male can insert his genital capsule . the photograph below shows the underside of a bombus sylvestris genital capsule .
comprehensive molecular studies include examination of relationships within the large new world subgenus fervidobombus , including dna sequences and morphology , by cameron & williams ( 2003 ) and sequence analysis of 37 of the 43 recognized pyrobombus species by hines , cameron & williams ( 2006 ) . in the present study , we report on the full hierarchy of bombus relationships for most of the world fauna , including rare and potentially endangered species such as bombus franklini and bombus occidentalis ( thorp , 2005 ) , exploiting the large number of characters available from dna sequences collected from multiple genes .
citation : nishimura o , brillada c , yazawa s , maffei me , arimura g - i ( 2012 ) transcriptome pyrosequencing of the parasitoid wasp cotesia vestalis : genes involved in the antennal odorant - sensory system . plos one 7 ( 11 ) : e50664 . urltoken
males of b . vestalis and b . terrestris produced in the lab were collected to sample cephalic secretions . in total four parasitized colonies , four parasitized colonies with emerged male parasites and four non - parasitized queenright colonies of b . terrestris were used for behavioral assays .
cameron sa : temporal patterns of division of labor among workers in the primitively eusocial bumble bee , bombus griseocollis ( hymenoptera : apidae ) . ethology . 1989 , 80 : 137 - 151 .
? bombus ( ps . ) monozonus ( friese ) monozonus ( friese , 1931 : 304 [ psithyrus ] ) not of friese , 1909 : 674 ( = b . lucorum ( linnaeus ) ) 1 name
dronnet s , simon x , verhaeghe jc , rasmont p , errard c . bumblebee inquilinism in bombus ( fernaldaepsithyrus ) sylvestris ( hymenoptera , apidae ) : behavioural and chemical analyses of host - parasite interactions .
je penche pour bombus ( psithyrus ) sylvestris . c ' est un bourdon coucou . il est répandu en europe ; depuis les latitudes nordiques de l ' asie , vers l ' est vers le . . .
rare and not recorded in scotland . she takes over the nests of bombus lapidarius . has darker wings than lapidarius . body lengths , female ( above left ) 22 mm , male ( above right ) 16 mm .
more common in the south , and not recorded in scotland * . she takes over the nests of bombus terrestris . body lengths , female ( above left ) 21 mm , male ( above right ) 16 mm .
in new zealand , where the winters are milder , bombus terrestris , introduced just over 100 years ago to pollinate clover , can forage throughout the year , and in such colonies the number of workers can reach thousands .
the authors are grateful to biobest bvba for having provided the colonies of bombus terrestris . we also thank roland de jonghe for his help in the rearing of bombus pascuorum , maryse vanderplanck for her help in the statistical analyses , klára urbanová for her help in the chemical compound identification , and jean - charles frémont for his help in the design of the figures . the manuscript was greatly improved by comments of anonymous three reviewers and the academic editor .
the two major components of the cephalic secretions of b . vestalis males are geranylcitronellyl acetate and geranylcitronellol ( [ 51 ] , [ 60 ] , table s1 ) . these compounds are not known to have a particular repellent effect in bumblebees and are probably involved in sexual attraction [ 50 ] , [ 61 ] . three other compounds , octadecenol , hexadecenyl acetate and tetradecyl acetate are present in the repellent secretions of b . norvegicus [ 25 ] and could thus play the same role in b . vestalis cephalic secretions . however octadecenol and hexadecenyl acetate are also present in the cephalic secretions of b . pascuorum . both should therefore not be the main compounds with a function as repellent allomone . in contrast , tetradecyl acetate is only present in the secretions of b . vestalis and is also known as a common molecule in the defensive secretions of several arthropods [ 62 ] . further studies will be needed to identify specific compounds involved in this allomonal effect .
common and takes over the nests of bombus pratorum and jonellus . body lengths , female ( above left ) 15 mm , male ( above right ) 14 mm . males tend to patrol mating circuits within 1 m off the ground .
van doorn a , heringa j : the ontogeny of a dominance hierarchy in colonies of the bumble bee bombus terrestris ( hymenoptera : apidae ) . insectes soc . 1986 , 33 : 3 - 25 . 10 . 1007 / bf02224031 .
sramkova a , schulz c , twele r , francke w , ayasse m : fertility signals in the bumblebee bombus terrestris . naturwissenschaften . 2008 , 95 : 515 - 522 . 10 . 1007 / s00114 - 008 - 0353 - 4 .
bombus phylogeny representing only the subgeneric relationships with strong support ( pp = 0 . 95 ) from the bayesian tree in fig . 1 . branches are colour - coded as in fig . 1 . values on branches are bayesian posterior probability values .
the subgenera within the former genus psithyrus have often been considered less distinct from one another than have the other subgenera of bombus ( pittioni , 1939 a ; ito , 1985 ; williams , 1985 b ; michener , 1990 ) and therefore may be treated as synonyms of psithyrus ( milliron , 1961 ; williams , 1991 , 1995 ) . in an alternative treatment , rasmont et al . ( 1995 ) included the former subgenera of the former genus psithyrus as separate subgenera within the genus bombus .
o’connor s , park kj , goulson d : worker drift and egg dumping by queens in wild bombus terrestris colonies . behav ecol sociobiol . 2013 , 67 : 621 - 627 . 10 . 1007 / s00265 - 013 - 1481 - 1 .
one poor bumblebee visited my brother and me recently . it was pretty exhausted but became happy after being fed with some honey ; ) this is a species belonging to the cuckoo bumblebees . this video shows our visiting male bombus ( psithyrus ) sylvestris or simply forest cuckoo bumblebee : ) being fed . it is quite common and takes over the nests of bombus pratorum and jonellus . body lengths , female 15 mm , male 14 mm . males tend to patrol mating circuits within 1 m of the ground .
in conclusion , our findings on the interactions between diploid males and females of c . vestalis confirm those of most previous studies on hymenoptera with csd : diploid males can mate but any offspring they get are sterile triploids . it thus appears that the findings of cowan and stahlhut ( 2004 ) of reproductively functional diploid males in e . foraminatus remain an exception .
diploid males in c . vestalis appear to behave normally in interactions with females , displaying wing fanning and mounting females . females also accept diploid males for mating . similar findings have been reported in , for example , the parasitoid wasp diadromus pulchellus ( el agoze et al . , 1994 ) and the ant lasius sakagamii ( yamauchi et al . , 2001 ) .
nesting behaviour : there is no worker caste and all species are obligate social parasites ( ' cuckoos ' ) in colonies of the other social bombus species ( reviewed by alford , 1975 ; fisher , 1987 ) . the degree of host specificity varies among species .
discriminant analysis . discriminant analysis of 116 bombus terrestris workers based on the 38 cuticular lipids retained for the analysis , showing discrimination among three classes of ovarian development . the percentages of variance explained by each of the two discriminant functions are provided on the axis labels .
cameron sa , hines hm , williams ph : a comprehensive phylogeny of the bumble bees ( bombus ) . biol j linn soc lond . 2007 , 91 : 161 - 188 . 10 . 1111 / j . 1095 - 8312 . 2007 . 00784 . x .
bombus ( ps . ) norvegicus ( sparre - schneider ) norvegicus ( sparre - schneider , 1918 : 40 [ psithyrus ] ) not of friese , 1911 : 571 ( = b . monticola smith ) transbaicalicus ( popov , 1927 : 269 [ psithyrus ] ) 10 names
amongst the compounds present in the secretions of b . vestalis , we identified hydrocarbons ( n - alkanes and n - alkenes ) , aliphatic alcohols , aldehydes , esters , and isoprenoids ( table s1 in supporting information ) . these results clearly show that nearly all the compounds found in the cephalic glands in seven days old males are already produced in the early days of their life .
bombus bohemicus , also known as the gypsy ' s cuckoo bumblebee , is a species of socially parasitic cuckoo bumblebee found in most of europe and the united kingdom with the exception of the southern iberian peninsula and iceland . b . bohemicus practices inquilinism , or brood parasitism , of other bumblebee species . b . bohemicus is a generalist parasite , successfully invading several species from genus bombus . the invading queen mimics the host nest ' s chemical signals , allowing her to assume a reproductively dominant role as well as manipulation of host worker fertility and behavior .
. . . additional evidence of the importance of a chemical background comes from social parasites that invade colonies to usurp the role of the queen . for example , the bumblebee , bombus terrestris , can be parasitized by congeners b . vestalis and b . bohemicus , whose hydrocarbon profiles mimic the complete chemical profile of the host queen and suppress host worker ovarian development [ 20 , 21 ] . if a single compound were sufficient for mimicking a queen , social parasites would not need to replicate or obtain more complete profiles and an individual with a profile lacking nestmate signals but displaying the correct fertility signals would be an omnipotent parasite of the host species . . . .
to study the behavior of and reproduction by diploid c . vestalis males , we used offspring from iso - female lines that were known to produce both haploid and diploid males ( de boer et al . , in preparation ) . these lines were set up to determine the number of loci on which csd is based in c . vestalis . in short , iso - female lines were started with a mother–son cross ( see de boer et al . , 2007 ) , using female offspring of outcrosses between two unrelated colonies of c . vestalis : colony a was started with about 200 adult wasps obtained from biofac crop care ( mathis , tx , usa ) and colony b was started with about 90 adult wasps from benin ( supplied by dr d bordat , cirad , montpellier - sur - lez , france ) . iso - female lines were maintained on diamond back moth larvae , plutella xylostella l . , for 6–8 generations of sibmating to ensure the production of diploid males before they were used in our experiment . in these generations , most lines produced between 30 and 50 % diploid males from fertilized offspring ( de boer et al . , in preparation ) .
nonparametric parsimony bootstrap trees estimated from morphological characters for 47 bombus subgeneric exemplars . a , analysis of the total morphology data set . b , analysis of genitalic characters alone . values above branches indicate bootstrap support ( bv ) > 50 % . subgeneric taxon labels are given in table 1 .
amsalem e , twele r , francke w , hefetz a : reproductive competition in the bumble - bee bombus terrestris : do workers advertise sterility ? . proc r soc lond b biol sci . 2009 , 276 : 1295 - 1304 . 10 . 1098 / rspb . 2008 . 1688 .
nous avons introduit des femelles de trois espèces européennes ( p . bohemicus , p . vestalis et p . compestris ) dans des colonies de laboratoire de leur hôte bombus ( b . lucorum , b . terrestris et b . pascuorum ) pouvant fourrager librement . pour chaque espèce de bourdon , nous avons étudié le développement d ' une colonie , où des parasites avaient été introduits avec succès . les femelles psithyrus ont cohabité avec les reines et les ouvrières hôtes , mais ont monopolisé le développement du couvain à travers l ' oophagie , l ' expulsion des larves , et les tentatives de dominer les bourdons hôtes . une partie du couvain psithyrus a été détruite aussi , et les bourdons hôtes des trois colonies ont réussi à élever du couvain de reproducteurs . les contacts sociaux prolongés entre les femalles psithyrus et leurs hôtes , ainsi que la possibilité de reproduction de l ' hôte au sein des colonies parasitées semblent indiquer que des complexités coévolutives dans les rapports bombus - psithyrus ne sont pas rares .
alaux c , boutot m , jaisson p , hefetz a : reproductive plasticity in bumblebee workers ( bombus terrestris ) – reversion from fertility to sterility under queen influence . behav ecol sociobiol . 2007 , 62 : 213 - 222 . 10 . 1007 / s00265 - 007 - 0455 - 6 .
nomenclature : because the type species of laboriopsithyrus was misidentified ( discussed by milliron , 1960 : 99 ) , the choice of type species to be designated should be made to serve nomenclatural stability ( iczn , 1999 : article 70 ) . williams ( 1998 ) suggested that , in the interests of stability ( iczn , 1999 : article 23 ) , the bumble bee species actually involved should be designated ( bombus laboriosus in the sense of frison , = bombus citrinus ( smith ) ) , which was wrongly named in the type fixation ( iczn , 1999 : article 70 . 3 . 2 ) .
figure s4 . argk . phylogeny of bombus estimated from bayesian analysis of arginine kinase nucleotide sequences . values above branches are bayesian posterior probabilities . the left hand portion of the figure connects via the dashed lines at the bottom to the dotted lines at the top of the right hand portion of the figure .
figure s5 . pepck . phylogeny of bombus estimated from bayesian analysis of phosphoenolpyruvate carboxykinase nucleotide sequences . values above branches are bayesian posterior probabilities . the left hand portion of the figure connects via the dashed lines at the bottom to the dotted lines at the top of the right hand portion of the figure .
dronnet s , simon x , verhaeghe jc , rasmont p , errard c : bumblebee inquilinism in bombus ( fernaldaepsithyrus ) sylvestris ( hymenoptera , apidae ) : behavioural and chemical analyses of host - parasite interactions . apidologie . 2005 , 36 : 59 - 70 . 10 . 1051 / apido : 2004070 .
bloch g , borst dw , huang zy , robinson ge , hefetz a : effects of social conditions on juvenile hormone mediated reproductive development in bombus terrestris workers . physiol entomol . 1996 , 21 : 257 - 267 . 10 . 1111 / j . 1365 - 3032 . 1996 . tb00863 . x .
this species was introduced to chile in 1998 . it has since crossed into argentina , and is spreading at about 275 km per year . its spread has been detrimental to populations of bombus dahlbomii , which is the only bumblebee species native to southern south america ( patagonia , southern chile and argentina ) .
figure s1 . 16s . phylogeny of bombus estimated from bayesian analysis of mitochondrial 16s rrna nucleotide data . values above branches are bayesian posterior probabilities . the left hand portion of the figure connects via the dashed lines at the bottom to the dotted lines at the top of the right hand portion of the figure .
discriminant analysis . discriminant analysis of 116 bombus terrestris workers based on the 38 cuticular lipids retained for the analysis , showing discrimination among five colonies . each colony is represented by a different colour and symbol combination . the percentages of variance explained by each of the three discriminant functions are provided on the axis labels .
in conclusion , we show that after emergence , males of the cuckoo bumblebee b . vestalis seem to produce a repellent odor that reduces host worker attacks during their intranidal life . we also demonstrate that social parasitism decreases worker aggressiveness towards alien individuals , possibly because of a decrease of host worker discrimination threshold . in addition to a chemical protection , male parasite offspring seem to be born in a facilitating social context that favors their acceptance by the host workers .
figure s3 . opsin . phylogeny of bombus estimated from bayesian analysis of long - wavelength rhodopsin copy 1 nucleotide sequences . values above branches are bayesian posterior probabilities . the left hand portion of the figure connects via the dashed lines at the bottom to the dotted lines at the top of the right hand portion of the figure .
has been commercially reared in new zealand since the early 1990s , and is now used in at least north africa , japan , korea , and russia , with the global trade in bumblebee colonies probably exceeding 1 million nests per year . in korea , however , some have chosen bombus ignitus over the already established commercial pollinator ,
we thank dominique bordat for supplying c . vestalis from benin , lynn knutson and beth sandager for rearing assistance , greg veltri of the flow cytometry core lab at the university of minnesota cancer center for his help in setting up the flow cytometry analyses and zhishan wu for letting us use facilities at the university of minnesota / minnesota department of agriculture quarantine facility . this study was supported by the us national science foundation and the university of minnesota agricultural experiment station .
bombus ( ps . ) bellardii ( gribodo ) bellardii ( gribodo , 1892 : 108 [ psithyrus ] ) examined pieli ( maa , 1948 : 29 [ psithyrus ] ) examined tajushanensis ( pittioni , 1949 : 277 [ psithyrus ] ) examined , not of pittioni , 1949 : 244 ( = b . bicoloratus cockerell ) 8 names
bombus ( ps . ) quadricolor ( lepeletier ) quadricolor ( lepeletier , 1832 : 376 [ psithyrus ] ) globosus ( eversmann , 1852 : 126 [ psithyrus ] ) meridionalis ( richards , 1928 b : 351 [ psithyrus ] ) not of dalla torre , 1879 : 13 ( = b . hortorum ( linnaeus ) ) 18 names
we surveyed sensory genes , especially for ors and obps , expressed in the antennae of c . vestalis adult females by roche 454 transcriptome pyrosequencing to partially evaluate the odorant - sensory systems . to date , transcriptome pyrosequencing is the most widely used system for de novo sequencing and analysis of transcriptomes especially in non - model organisms . in addition , the or and some of obp genes identified were examined in order to evaluate their tissue and gender - specific patterns of expression .
figure s2 . ef - 1∝ . phylogeny of bombus estimated from bayesian analysis of elongation factor - 1alpha f2 copy nucleotide sequences . values above branches are bayesian posterior probabilities . the left hand portion of the figure connects via the dashed lines at the bottom to the dotted lines at the top of the right hand portion of the figure .
after emerging from hibernation during april the mated female seeks out a small b . terrestris nest with a few workers . the female sneaks into the nest and hides while it acquires the nest scent . it may dominate , or kill , the host queen and takes over the egg laying for the colony . these eggs produce only new b . vestalis females and males , which take no part in the running of the colony , all work being done by the host workers .
the qualitative and quantitative composition of the cephalic secretions of b . vestalis , b . terrestris and b . pascuorum clearly demonstrate the species - specificity of these secretions ( table s2 in supporting information ) . among the 71 compounds identified , 48 are species - specific ( 16 / 30 in b . terrestris , 18 / 37 in b . pascuorum and 14 / 30 in b . vestalis ) . only seven compounds are common to the three species , four alkanes : heneicosane ( n - c 21 ) , tricosane ( n - c 23 ) , pentacosane ( n - c 25 ) and heptacosane ( n - c 27 ) ; and three alkenes : pentacosene ( n - c 25 : 1 ) , heptacosene ( n - c 27 : 1 ) and nonacosene ( n - c 29 : 1 ) . host and parasite share only 10 compounds , while they both share more with b . pascuorum ( 11 and 13 respectively , table s1 ) .
nomenclature : with psithyrus regarded as being a subgenus of the genus bombus ( williams , 1991 , 1995 ) , p . norvegicus sparre - schneider ( 1918 ) becomes a junior secondary homonym in bombus of b . lapponicus var . norvegicus friese ( 1911 ) ( deemed subspecific , see iczn , 1999 : article 45 . 6 ) , and therefore p . norvegicus sparre - schneider is invalid ( iczn , 1999 : article 57 . 3 ) . for this species , the oldest available name of which i am aware is p . norvegicus var . transbaicalicus popov , 1927 ( deemed to be subspecific , see iczn , 1999 : article 45 . 6 ) , so b . transbaicalicus would become the valid name .
additional file 2 : discriminant analysis . discriminant analysis of 116 bombus terrestris workers based on the 38 cuticular lipids retained for the analysis , showing discrimination among five colonies . each colony is represented by a different colour and symbol combination . the percentages of variance explained by each of the three discriminant functions are provided on the axis labels . ( pdf 41 kb )
concerning the new world clade , rather than recognizing even more monotypic subgenera , it might be more practical to recognize the entire new world clade as a single subgenus consisting of several species groups , including robustobombus . further reductions in numbers of subgenera could be achieved by placing obertobombus ( bombus oberti ) into sibiricobombus , and by including festivobobombus ( bombus festivus ) and rufipedibombus in melanobombus . whether to consolidate these taxa into one group is complicated by the fact that many of the monotypic subgenera are sister to clades subtended by conspicuously long branches , suggesting long separation / distinctness ( fig . 1 ) . in view of these apparently large intersubgeneric genetic distances , it might be prudent to consider additional biological characters in decisions as to whether to combine the taxa .
the missing putative species ( williams , 1998 ) from this study are most notably from psithyrus ( eight species ) , mendacibombus ( five species ) and melanobombus ( four species ) . examination of the positions of these and remaining species from small subgenera ( e . g . , cullumanobombus , rufipedibombus , senexibombus , and orientalibombus ) would secure our knowledge of bombus relationships and subgeneric monophyly .
cuckoo bumblebees ( subgenus psithyrus ) are social parasites in colonies of their host bumblebee species ( bombus ) . in spring , parasitic females awaken from hibernation and start searching for established host nests . some psithyrus species are specialized on one host species , whereas generalists parasitize several species . in previous investigations , nest - marking signals of the bumblebee hosts . . . [ show full abstract ]
bumblebees of the subgenus psithyrus are obligate social parasites of bombus colonies . parasitic females enter host colonies and replace the host queen . the offspring of the parasite is reared by the host workers . females locate host colonies by nest searching flights and recognition of species - specific nest odours at the entrance . we investigated inter - and intraspecific odour variation of 45 . . . [ show full abstract ]
molecular function distributions from the gene ontology ( go ) analyses showed that in c . vestalis the genes expressed in the antennae were mostly linked to molecular binding activity ( e . g . , nucleotide , ion and odorant binding ; in 47 % of the total scores ) or categorized as catalysts ( e . g . , hydrolase and oxidoreductase ; in 36 % of the total scores ) ( figure 2 ) . the contigs / singletons involved in molecular transporters and transducers ( including odorant receptors ) constitute the next most abundant categories amounting to 7 and 3 % , respectively .
bombus ( ps . ) rupestris ( fabricius ) rupeftris [ rupestris ] ( fabricius , 1793 : 320 [ apis ] ) examined pyrenæus [ pyrenaeus ] ( lepeletier , 1832 : 375 [ psithyrus ] ) interruptus ( lepeletier , 1832 : 381 [ psithyrus ] ) armeniacus ( reinig , 1970 : 77 [ psithyrus ] ) not of radoszkowski , 1877 b : 202 ( = b . armeniacus radoszkowski ) 70 names
premating behavior in the bumblebee bombus confusus was studied . visual searching for females is not the only premating strategy of this species , as was believed earlier . males of b . confusus have a normally developed labial gland and its secretion is used to mark a perch from which they visually search for females . the labial gland secretion contains geranylcitronellol and ( z ) - 9 - octadecenyl acetate as the main components .
simultaneous bayesian analysis of the combined sequence data produced a tree with nearly complete resolution and high branch support at all levels ( fig . 1 , table 2 ) . of the 204 bombus nodes in the tree , all but 12 were resolved and 158 ( 77 % ) were supported by posterior probability values > 0 . 95 . relationships among subgenera indicated by high support ( pp > 0 . 95 ) are summarized in fig . 2 .
bombus ( ps . ) chinensis ( morawitz ) chinensis ( morawitz , 1890 [ april 30 ] : 352 [ apathus ] ) examined morawitzi ( friese , 1905 : 516 [ psithyrus ] ) examined , not of radoszkowski , 1876 : 101 ( = b . morawitzi radoszkowski ) hönei [ hoenei ] ( bischoff , 1936 : 26 [ psithyrus ] ) examined , not of bischoff , 1936 : 10 ( = b . friseanus skorikov ) 3 names
identifying potential parasites at the entrance of the nest requires assessing both the colonial membership and the fertility of the intruders . we actually found that the cuticular compounds of bumble bees convey both types of information , therefore allowing the evolution of a specific defensive strategy against worker reproductive parasitism by bombus terrestris guards . behavioural analyses indeed proved that even though guard bees could discriminate nestmates from non - nestmates , only fertile intruders triggered a rise in the agonistic response .
bombus ( ps . ) cornutus ( frison ) cornutus ( frison , 1933 : 338 [ psithyrus ] ) pyramideus ( maa , 1948 : 19 [ psithyrus ] ) examined acutisquameus ( maa , 1948 : 21 [ psithyrus ] ) examined klapperichi ( pittioni , 1949 : 273 [ psithyrus ] ) examined , not of pittioni , 1949 : 266 ( = b . picipes richards ) canus ( tkalcu , 1989 : 42 [ psithyrus ] ) examined 5 names
mating usually takes place while resting on the ground or on vegetation , but there have been sightings of large queens flying with small males attached to them . . all the photographs above show that the mating is successful . at the start of mating the male grabs on to the queen ' s thorax to get himself into the correct position , this can be seen below in the bombus lucorum photograph , only when everything is in position does he move back .
the triploid nature of the daughters of diploid males implies that diploid c . vestalis males produce diploid sperm . diploid males of the related c . glomerata also produce diploid sperm ( zhou et al . , 2006 ) but it has not been determined whether females of this species mate with diploid males and produce triploid offspring . with the exception of e . foraminatus ( cowan and stahlhut , 2004 ) , diploid males of all species that have been studied so far produce diploid sperm and triploid progeny , if any ( for example , hoshiba et al . , 1981 ; chauvin et al . , 1987 ; yamauchi et al . , 2001 ) .
we analyzed the effect of triploid females on their hosts by using a generalized logits model ( proc logistic , sas institute inc . , 2006 ) to compare the proportion of hosts that died , developed into moths or developed into cocoons , with a set of control hosts . the controls consisted of hosts that were treated in the same way but were not exposed to a c . vestalis female . the two sets of hosts offered to each triploid female ( before and after mating ) were combined because we found no differences between the two sets in the number of offspring produced or the proportion of hosts that died ( t - tests , p > 0 . 05 ) .
. . . during the initial phase of the colony life cycle , dominant fecund queens suppress workers ' ovarian development by behavioral and pheromonal mechanisms ( röseler & röseler 1977 ; van honk et al . 1980 ; röseler et al . 1981 ) . it has been shown that psithyrus species have the same ability to suppress host workers ' ovarian development as the real queen ( vergara et al . 2003 ; kreuter et al . 2012 ) . fully dominated workers are less disposed to be controlled by the usurper so it is preferable ( in the case of queen - intolerant inquilines such as b . vestalis ) to remove the host queen to facilitate psithyrus female domination of host workers . . . .
contigs and singletons with at least one match to ors and obps and with an e - value of 1e - 5 or lower were selectively annotated . blast search indicated that ors were predicted in 64 contigs and 99 singletons , and that obps were predicted in 74 contigs and 71 singletons ( tables 2 , 3 , s2 and s3 ) . the number of predicted obp contigs regenerated from at least 10 reads were 22 ( table 3 ) , but only six were regenerated from or contigs ( table 2 ) . therefore , in the antennae of female c . vestalis , obp genes appeared to be expressed more abundantly than or genes . obp1 and obp2 in particular were expressed at remarkably high levels .
the results of our second experiment shows that host workers exhibit a diminishing degree of aggression in parasitized colonies compared to non - parasitized ones . this suggests that social parasitism reduces host worker aggressiveness . sramkova and ayasse [ 39 ] recently demonstrated that b . vestalis females are able to selectively kill older host workers that directly compete with them for reproduction . the old workers are more likely to possess developed ovaries and are among the first egg - layers [ 63 ] , [ 64 ] . they are the dominant and also the most aggressive ones . the psithyrus females use this worker discrimination ability to maintain reproductive dominance and maximize their reproductive success . this strategy could also explain the reduced aggressiveness of parasitized colony .
bombus trees summarizing the basal relationships for each of four nuclear genes . a , summary consensus of the four individual gene trees : ef - 1α ( b ) , opsin ( c ) , argk ( d ) , and pepck ( e ) . kl , kallobombus ; bi , bombias ; cf , confusibombus ; md , mendacibombus . sf and lf refer to the short - faced and long - faced clades , respectively . proportions shown on the branches of individual gene trees are bayesian posterior probabilities .
bombus ( ps . ) insularis ( smith ) interruptus greene , 1858 : 11 , not of lepeletier , 1832 : 381 ( = b . rupestris ( fabricius ) ) insularis ( smith , 1861 : 155 [ apathus ] ) examined consultus ( franklin , 1913 : 459 [ psithyrus ] ) ? bicolor ( franklin , 1913 : 460 [ psithyrus ] ) not of höppner , 1897 : 33 ( = b . soroeensis ( fabricius ) ) crawfordi ( franklin , 1913 : 464 [ psithyrus ] ) examined 5 names
of the 11 recognized monotypic subgenera ( table 1 ) , most of their relationships to other taxa were well resolved with good support ( figs 1 , 2 ) . notably , the attachment of exilobombus ( b . exil ) within tricornibombus was strongly supported ( pp = 1 . 0 ) , as was the placement of pressibombus ( = b . pressus ) as sister to bombus infirmus within pyrobombus ( pp = 0 . 99 ; fig . 1 ) . sister group relationships of the monotypic subgenera are summarized in table 3 .
. . . interestingly , secretions are used alternatively by insect parasites frequently to evade hosts . the cuckoo bee , bombus bohemicus , infiltrates host hives by mim - icking that colony ' s cuticular secretions , where it goes on to monopolize resources for reproduction and suppress host reproduction ( kreuter et al . 2012 ) . in comparison , the social parasite , acromyrmex insin uator , infiltrates host nests by appearing ' chemically insignificant ' , not secreting cuticular hydrocarbons or any other pheromones ( lambardi et al . 2007 ) . . . .
the photograph below bombus impatiens mating . b . impatien s is a bumblebee native to the eastern u . s . , but is also found in the western states . the photograph below shows clearly the size difference between the male and the queen . also the creamy yellow hair on the male ' s
nose
. in this species males often have hair that is a brighter colour than the queen and workers . the image below was sent in by a visitor to the urltoken site . new queens usually search for a hibernation site soon after mating .
. . . scouts of european honeybees are known to fight with workers from competing colonies while locating nest sites , and this can lead to mobbing and killing of those in the minority ( rangel et al . 2010 ) . fights to the death between queens of primitively eusocial bee and wasp species occur when an usurping queen invades another ' s nest ( zobel and paxton 2007 ) , and queen fight - ing also occurs in bumblebees in the subgenus psithyrus , which are obligate parasites on bombus bumblebee species ( kreuter et al . 2012 ) . . . .
bombus ( ps . ) sylvestris ( lepeletier ) sylvestris ( lepeletier , 1832 : 377 [ psithyrus ] ) brasiliensis ( smith , 1854 : 385 [ apathus ] ) examined , not of lepeletier , [ 1835 ] : 470 ( = b . brasiliensis lepeletier ) citrinus ( schmiedeknecht , 1883 [ see baker , 1996 c : 297 ] : 23 [ 407 ] [ psithyrus ] ) not of smith , 1854 : 385 ( = b . citrinus ( smith ) ) [ silvestris ( dalla torre , 1896 : 571 [ psithyrus ] ) incorrect subsequent spelling ] 24 names
phylogeny of bombus estimated from bayesian analysis of combined sequence data from five gene fragments ( 16s , opsin , argk , ef - 1α , and pepck ) . subgeneric clades are individually colour - coded and labelled with the subgeneric name . values above branches are bayesian posterior probabilities ; values below branches are parsimony bootstrap values . alternative resolution from parsimony analysis shown as dotted lines . outgroup branches ( in grey ) , represented by dashed lines , have been shortened for visual purposes . nw , new world clade ; sf , short - faced clade ; lf , long - faced clade .
bombus ( ps . ) bohemicus seidl nemorum ( fabricius , 1775 : 380 [ apis ] ) examined , not of scopoli , 1763 : 307 ( = b . subterraneus ( linnaeus ) ) , not of fabricius , 1775 : 382 ( = b . distinguendus morawitz ) bohemicus seidl , 1837 : 73 ashtoni ( cresson , 1864 : 42 [ apathus ] ) ? chinganicus ( reinig , 1936 : 8 [ psithyrus ] ) hedini ( bischoff , 1936 : 26 [ psithyrus ] ) examined , not of bischoff , 1936 : 15 ( = b . hedini bischoff ) 43 names
bombus ( ps . ) campestris ( panzer ) campeftris [ campestris ] ( panzer , 1801 ( 74 ) : 11 [ apis ] ) varius ( lepeletier , 1832 : 381 [ psithyrus ] ) flavus ( pérez , 1884 : 265 [ psithyrus ] ) flavo - thoracicus [ flavothoracicus ] ( hoffer , 1889 : 49 [ psithyrus ] ) ? susterai ( tkalcu , 1959 : 251 [ psithyrus ] ) examined , not of may , 1944 : 267 ( = b . maxillosus klug ) ? susteraianus ( tkalcu , 1977 : 224 [ psithyrus ] ) replacement name for susterai tkalcu , 1959 : 251 32 names
the left half of the table indicates resolution ( number of internal nodes resolved ) and node support ( pp = posterior probability ) for the conventional bombus subgenera from bayesian analyses of the combined sequences from five genes . in the right half of the table , posterior probability values are reported for subgeneric monophyly based on individual gene sequences . abbreviations of subgeneric names are given in table 1 . the 12 monotypic subgenera ( table 1 ) are not listed , nor are subgenera comprising two species for which we have only one representative ( br , fn , ob , rf ) . u , unresolved ; pa , paraphyletic ; po , polyphyletic
data for b . pratorum ( a ) and all bombus species ( b ) pooled . the sites are arranged from large populations ( sacrawé = sac , fange aux mochettes = fam ) to small ( wé de pourceaux = wdp , grande fange = gf ) ; open , patchy populations are marked with grey boxes . different letters indicate significant differences ( p < 0 . 05 ) according to mann - whitney - u tests ( a ) or glmm ( b ) . figures in boxes stand for sample sizes . standard box plots with lines = median , boxes = 25 % and 75 % , whiskers = minimum and maximum without outliers .
there is some evidence that bombus pratorum and b . hortorum may , under certain circumstances , be able to go through two colony cycles in a year . this would mean that instead of hibernating the new queens would immediately start a colony and the queens that emerge from this colony would then hibernate through the winter . b . pratorum and b . hortorum usually have quite small colonies , and b . pratorum colonies can reach their maximum size earlier in the year than any other species . this has been reported in the south of england where the winters have been milder recently , and there is plentiful pollen and nectar available from non - native flowers .
this chemical plasticity is also involved in parasitic associations of ants , bees and wasps [ 28 ] , [ 70 ] , [ 71 ] . social parasites are able to acquire conspecific host odors but also to add their own recognition cues to the host colony profile [ 72 ] . as in mixed - species groups , odors of social parasites may thus influence nestmate discrimination [ 73 ] – [ 75 ] . lorenzi [ 76 ] has shown in polistes wasps that the increased complexity of colony - profile in parasitized colonies affects the ability of host workers to distinguish between nestmates and non - nestmates . it suggests that parasite - specific compounds modify host colony odor and thus force the workers to update the learned template to a new one that incorporates the heterospecific compounds . the presence of b . vestalis females could thus result in a decrease of host worker recognition abilities that could facilitate acceptance of the parasite ' s offspring .
bombus comprises the monotypic tribe bombini , which together with apini ( honey bees ) , meliponini ( stingless bees ) , and euglossini ( orchid bees ) , constitutes the corbiculate bees , distinguished by the pollen - carrying structure ( corbicula ) on the hindleg . their closest relatives , estimated from dna sequences of multiple genes , are the stingless bees ( cameron , 1993 , 2003 ; mardulyn & cameron , 1999 ; cameron & mardulyn , 2001 , 2003 ; lockhart & cameron , 2001 ; thompson & oldroyd , 2004 ) , although some morphological data ( roig - alsina & michener , 1993 ; schultz , engel & ascher , 2001 ) place them as sister to honey bees + stingless bees .


the deepwater sculpin ( myoxocephalus thompsonii ) is a freshwater sculpin that inhabits the bottoms of cold , deep freshwater lakes of northern north america .

its distribution ranges from the great bear lake of canada to the great lakes .

it is a designated at-risk fish species in canada , protected as a species of special concern under canada 's species at risk act .

the deepwater sculpin is generally gray-brown with mottling on its head , back , and sides with a whitish underside .

when full-grown , they are usually between 4 and 6 inches ( 10 – 15 cm ) , but they can reach to 9 inches ( 23 cm ) .

they weigh less than an ounce ( < 25 g ) .

they are a bottom-feeding species , which makes them vulnerable to a build-up in contaminants in polluted lakes .

they were considered extinct in lake erie and lake ontario , but have recently been rediscovered there .

they mostly eat tiny crustaceans and aquatic insects and are eaten by lake trout and other predatory fish .

deepwater sculpin

like other sculpin species , male deepwater sculpin build nests and guard the eggs .
it may be that competition between sculpin species led to a decline in deepwater sculpin . young deepwater sculpin and slimy sculpin eat the same foods and use the same habitats . slimy sculpin may also prey on the eggs and larvae of deepwater sculpin . competition with slimy sculpin might have contributed to the decline in deepwater sculpin .
it may be that competition between sculpin species contributed to a decline in deepwater sculpin . data on competitive feeding habits of various sculpin species are limited , however , juvenile deepwater sculpin and slimy sculpin (
data on food preference is based on stomach contents of captured fish . deepwater sculpin eat mainly crustaceans , especially deepwater amphipods and opossum shrimp . larger sculpins prefer deepwater amphipods .
because it is so difficult to study deepwater sculpin , little is known about their mating systems .
notes on the life history of the deepwater sculpin , myoxocephalus quadricornis l . , in lake superior
mottled sculpin x slimy sculpin reported from wisconsin but unconfirmed ; known from elsewhere ( no photos ) .
deepwater sculpin are widespread in lakes superior and huron , although they may be in decline in the latter .
adult deepwater sculpin are generally found in waters deeper than 20 meters and are especially abundant between 70 and 90 meters deep . in lake superior they have been found at depths of 407 meters . the largest deepwater sculpin individuals are found in the deepest waters . deepwater sculpin live only in cold water , 40 degrees celsius or less .
declines in deepwater sculpin myoxocephalus thompsonii energy density associated with the disappearance of diporeia spp . in lakes huron and michigan
deepwater sculpin myoxocephalus thompsonii are an important component of great lake ' s offshore benthic food webs . recent declines in deepwater sculpin abundance and changes in bathymetric distribution may be associated with changes in the deepwater food web of lake huron , particularly , decreased abundance of benthic invertebrates such as diporeia . to assess how deepwater sculpins have . . . [ show full abstract ]
) have over - lapping food preferences and habitat use , creating the potential for competition . there is also evidence that slimy sculpin prey on the eggs and larvae of deepwater sculpin .
although research is ongoing , due to the deepwater sculpin’s inaccessible habitat , there is little concrete documentation of their developmental stages .
there are currently two known threats to the continued survival of deepwater sculpin . the first is the loss of their main prey , deepwater amphipods . the second threat is the presence of an introduced species : round gobies . round gobies are fierce fighters , and often push deepwater sculpin out of foraging and breeding areas .
mm ) generally increased until a peak in 2013 . in addition , the mean length of all deepwater sculpin captured in a trawl significantly increased with depth . across all years examined , deepwater sculpin densities generally increased with depth , increasing sharply at depths >
there isn ' t much known about development in deepwater sculpin because they are difficult to study . deepwater sculpin undergo changes from egg to open - water larvae to bottom - dwelling juvenile ( young ) within their first year of life . this first year is a time of rapid growth in length , after which the growth in length slows and deepwater sculpin grow both in length and weight .
the prickles on the top of the body and the four spines on top of the head may make it difficult for predators to eat deepwater sculpin . also , deepwater sculpin spend most of their time in very cold and deep places , where there are few predators .
from 1942 to 1972 , no deepwater sculpin were captured in lake ontario . between 1972 and 2002 , only six were caught . despite their disappearance from lake ontario and steady decline in the other great lakes , the united states fish and wildlife service ( usfws ) does not list deepwater sculpin as being a species of concern for the great lakes region . the new york state department of environmental conservation and the canadian government list deepwater sculpin as being threatened and monitored . current research focuses on figuring out how many deepwater sculpin are left in the great lakes and other deep water lakes in canada . the decline of deepwater sculpin may have been linked to the introduction of two non - native species in the great lakes : alewives and rainbow smelt . both of those fish species eat deepwater sculpin eggs and compete with them for food .
brandt , s . 1986 . disappearance of the deepwater sculpin ( * myoxocephalus thompsonii * ) from lake ontario : the keystone predator hypothesis .
ann arbor , mi — despite recent and unprecedented declines in their favorite invertebrate prey , lake michigan slimy and deepwater sculpin are not starving .
the deepwater sculpin can be distinguished by its pair of free and independent pelvic fins and its lack of scales . see also similar species information .
. . . slimy and deepwater sculpin appeared to exploit opposite ends of the diporeia size continuum , with deepwater sculpin selecting larger diporeia than slimy sculpin . this may be important for mediating interspecific competition because diporeia represents a significant fraction of the diet biomass of both sculpin ( wells , 1980 ; wojcik , et al . , 1986 ; selgeby , 1988 ; hondorp et al . , 2005 ; o ' brien et al . , 2009 ; french et al . , 2010 ) . consequently , slimy and deepwater sculpin may reduce diet overlap even when alternate prey types are unavailable . . . .
deepwater sculpins ( myoxocephalus thompsonii ) are an important link in deepwater benthic foodwebs of the great lakes . little information exists about deepwater sculpin spawning habits and early life history ecology due to difficulty in sampling deep offshore habitats . larval and age - 0 deepwater sculpins collected in northern lake huron and the detroit river during 2007 were used to improve our . . . [ show full abstract ]
parker , b . j . 1988 . status of deepwater sculpin , myoxocephalus thompsoni , in canada . canadian field - naturalist 102 : 126 - 131 .
wojcik , j . , m . evans , d . jude . 1986 . food of deepwater sculpin , * myoxocephalus thompsonii * , from southeastern lake michigan .
m . bottom trawl observations suggest the lake ontario deepwater sculpin population has recovered and current densities and biomass densities may now be similar to the other great lakes .
there are currently two known threats to the continued survival of deepwater sculpin . the first is the loss of the amphipod pontoporeia from the majority of the bottom of lake michigan . as one of their main food sources , the loss of this important food source will substantially impact the recruitment of deepwater sculpin . the second threat is the presence of invasive round gobies in off - shore waters that overlap the distribution of spawning sites for deepwater sculpin . round gobies are fierce fighters , and often out - compete sculpin species in the same area ( jude et al . , 2002 ) .
deepwater sculpin are found in the deep , cool lakes of northern north america . they were once abundant in the great lakes and most deep lakes of canada ( especially nipigon in ontario , great slave in manitoba , waterton in alberta , and great bear in the northwest territories ) , but the range of deepwater sculpin is rapidly shrinking .
anti - predation mechanisms have barely been studied in deepwater sculpin . the prickles on the top of the body and the four spines on top of the head may serve as deterrents to predators . in addition , the fact that deepwater sculpin spend most of their time under conditions few other species can withstand , limits their interaction with potential predators .
ontogenetic changes occur during the deepwater sculpin’s first year of life , transforming them from pelagic larva to benthic organisms as juveniles , and eventually as adults ( bruch , 1986 ) .
currently , deepwater sculpin are plentiful in lakes huron , michigan and superior , and rare in ontario and erie . despite their deepwater habitat requirements , they are also sometimes found in the inland waterways that connect the great lakes , such as the st . claire river .
additional methods in this research will allow for first - time estimations of exactly how many fish eggs or how many other prey sculpin consume , adding to the ability to better manage great lakes fisheries and increasing the knowledge of roles sculpins play in the foodweb . results support that slimy and deepwater sculpin restoration and recovery efforts could work in lake ontario where presently deepwater sculpin exist marginally or are extirpated , slimy sculpin populations are reduced , and diporeia have been extirpated as a result of recent and similar environmental changes as lake michigan has experienced .
at present , deepwater sculpin are plentiful in lakes huron , michigan and superior , and rare in ontario and erie . despite their deepwater habitat requirements , they are also found occasionally in the inland waterways that connect the great lakes , such as the st . claire river .
black , g . , m . lankester . 1981 . the biology and parasites of deepwater sculpin , * myoxocephalus quadricornis thompsonii * ( girard ) , in burchell lake , ontario .
adult deepwater sculpin are generally found in waters deeper than 20 meters and are particularly abundant between 70 and 90 meters . in lake superior they have been found at depths of 407 meters . although all adults are benthic , the largest fish of a population are found in the deepest waters . deepwater sculpin live only in cold water , 40 degrees celsius or less .
) needed to invoke the criterion response is plotted versus wavelength ( nm ) for kiyi ( black circles ) , siscowet ( open circles ) , and deepwater sculpin ( triangles ) .
no management activities specific to deepwater sculpin are currently occurring in montana . the only known location for montana is within the boundaries of glacier national park and waterton lake national park , alberta . surveys conducted at upper waterton lake , which overlaps the international boundary , have captured deepwater sculpin in the canadian portion ( mcallister and ward 1972 , sheldon et al . 2008 ) ; the u . s . portion has not been sampled . surveys of other deepwater lakes in and near glacier national park would be useful , as well as routine surveys of upper waterton lake ( including the u . s . portion ) to determine the status and distribution of deepwater sculpin in that lake .
) . again , all species demonstrated similar profiles with maximum sensitivity between 500 and 525 nm , with the deepwater sculpin retaining a slight advantage in detection of wavelengths between 500 and 575 nm .
fish life history , diets , and habitat use in the northwest territories : freshwater sculpin species .
deepwater sculpin currently are not seen as having any commercial value or economic importance on a local , national or international scale . they are important members of the native great lakes and northern lakes ecosystem .
despite their disappearance from lake ontario and steady decline in the other great lakes , the united states fish and wildlife service ( usfws ) does not list deepwater sculpin as even being a species of concern for the great lakes region ( nysdec , 2002 ) . they are however , listed by the new york state department of environmental conservation and the canadian government as being threatened and monitored ( nysdec , 2002 , cosewic , 2001 ) . research efforts are underway to determine how many deepwater sculpin are left in the great lakes and the other deep water lakes of canada . the decline of deepwater sculpin may have been linked to the introduction of two non - native species in the great lakes : alewives and rainbow smelt . both of those fish species eat deepwater sculpin eggs and compete with them for food .
deepwater sculpin live in very dark environments . little is known about their modes of perception and how they might communicate , but it is likely that they use tactile and chemical perception in their dark habitat .
hondorp , d . w . , s . a . pothoven , and s . b . brandt . 2011 . feeding selectivity of slimy sculpin cottus cognatus and deepwater sculpin myoxocephalus thompsonii in southeast lake michigan : implications for species coexistence . journal of great lakes research 37 ( 1 ) : 165 - 172 .
during their first year of life , deepwater sculpin are found in the open water feeding on plankton and small invertebrates . as they age their body shape and physiology changes and they become bottom - dwelling fish .
the very large gap between the dorsal fins distinguishes deepwater sculpin from other sculpins in montana . the tips of the rays on the 2nd dorsal fin extend freely beyond the fin , also unlike in other montana sculpins .
brandt , s . b . 1986 . disappearance of the deepwater sculpin ( myoxocephalus thompsoni ) from lake ontario : the keystone predator hypothesis . journal of great lakes research 12 ( 1 ) : 18 - 24 .
during their first year , deepwater sculpin are pelagic , rather than benthic organisms . they live in the water column feeding on pelagic phytoplankton and small invertebrates . as they age they undergo physiological changes and become benthic organisms .
the department of environmental conservation will continue to track and report on observations of deepwater sculpins in new york waters .
predators of deepwater sculpin include lake trout ( salvelinus namaycush ) and burbot ( lota lota ) ( mcallister et al . , 1979 ) . by the early 1950s , lake trout and burbot were nearly extirpated from lake ontario after falling victim to over - fishing and sea - lamprey parasitism . shortly after the population declines of these two keystone predators , deepwater sculpin disappeared from lake ontario for almost the next 50 years . it is believed that the loss of these keystone predators resulted in huge disruptions to this freshwater fish community and deep population declines of sculpin .
mcallister , d . e . and j . c . ward . 1972 . the deepwater sculpin , myoxocephalus quadricornis thompsoni , new to alberta , canada . journal of fisheries research board of canada 29 : 344 - 345 .
the deepwater sculpin , abundant in lake ontario until 1980 , was considered extirpated from this lake until caught in waters in 1996 , 1998 and 1999 . they were caught in lake erie as recently as 1995 . the cause of the sculpins ' population decline is unknown . however , scientists theorize that alewives and rainbow smelt may have contributed to the decline because they eat sculpin eggs and larvae . in addition , alewives and rainbow smelt compete with deepwater sculpins for food .
the deepwater sculpin is a benthic invertivore , feeding on deepwater crustaceans ( amphipods ) ; and larval chironomids ( black and lankester 1981 , brandt 1986 ; kraft and kitchell 1986 ) . in lake huron and lake michigan , mysis relicta forms the primary diet , supplemented with diporeia species ; both are glacial - relict crustaceans ( hondorp et al . 2011 ) .
predators of deepwater sculpin include lake trout and burbot . by the early 1950s , over - fishing and sea lamprey parasitism of lake trout and burbot resulted in their near disappearance from lake ontario and severe declines in other great lakes . shortly after the population declines of these two keystone predators , deepwater sculpin disappeared from lake ontario for almost the next 50 years . it is thought that the loss of these keystone predators resulted in huge disruptions to the great lakes freshwater fish community .
diet and habitat use by age - 0 deepwater sculpins in northern lake huron , michigan and the detroit ri . . .
the deepwater sculpin is found in deep , cool waters of mainland lakes in northern north america , from the great bear lake in canada to the great lakes . in new york state , the fish has been found in lakes ontario and erie .
the deepwater sculpin inhabits the bottoms of deep lakes and is an important forage fish for lake trout , burbot , and other cold water piscivores ( scott and crossman 1973 ) . it feeds on deepwater crustaceans ( amphipods ) and larval chironomids . a 2004 survey of 35 lakes across their range never found deepwater and spoonhead sculpins ( cottus ricei ) together within the same lakes , suggesting competition between these two species ( sheldon et al . 2008 ) . in lake michigan , deepwater sculpin accounts for 30 % of fish biomass caught in bottom trawls ( bunnell et al . 2009 ) . energy density of sculpins declined in lake michigan with the collapse of diporeia prey ( hondorp et al . 2011 ) . two deepwater sculpins were captured in upper waterton lake in august 1966 , 28 were captured during may to october 2004 , using benthic fish traps , gill nets , and otter trawls ; population size in the lake is unknown . nine of 10 deepwater sculpins from upper waterton lake were infected with immature forms of the internal parasite bothriocephalus cuspidatus , and four of ten with immature proteocephalus sp . adults of these parasites are found in lake trout or burbot , both of which are important predators of deepwater sculpins . thus , the diet of deepwater sculpins reflects the mode of parasite recruitment through its main prey of crustaceans ( which host immature stages of the parasites ) ; furthermore , deepwater sculpins play a role in the life cycle of these parasites by transmitting them to deepwater picivorous fish ( carney et al . 2009 ) .
sheldon , t . a . , n . e . mandrak , and n . r . lovejoy . 2008 . biogeography of the deepwater sculpin ( myoxocephalus thompsonii ) , a nearctic glacial relict . canadian journal of zoology 86 : 108 - 115 .
deepwater sculpin have been known to reach 9 inches ( 23 cm ) in length , although the average is between 2 and 5 inches ( 5 to 10 cm ) . the body is slender , with a large flattened head and blunt snout with a large mouth . the eyes are set close together on top of the flattened head . there are two dorsal ( back ) fins , the second much larger than the first . in large males , this second dorsal fin often overlaps the base of the caudal ( tail ) fin . although deepwater sculpin do not have scaled skin , they do have prickles on top of the body . deepwater sculpin are grayish brown with a slightly lighter belly . the back and sides are speckled with thin oval - shaped marks .
carney j . p . , t . a . sheldon , and n . r . lovejoy . 2009 . parasites of the deepwater sculpin ( myoxocephalus thompsonii ) across its canadian range . the journal of parasitology 95 ( 5 ) : 1209 - 12 .
black , g . a . and m . w . lankester . 1981 . the biology and parasites of deepwater sculpin , myoxocephalus quadricornis thompsonii ( girard ) , in burchell lake , ontario . canadian journal of zoology 59 ( 7 ) : 1454 - 1457 .
deepwater sculpin are important in oligotrophic lakes as one of the few fishes that use deep profundal habitats and link invertebrates in those habitats to piscivores . in lake ontario the species was once abundant , however drastic declines in the mid - 1900s led some to suggest the species had been extirpated and ultimately led canadian and u . s . agencies to elevate the species ' conservation status . following two decades of surveys with no captures , deepwater sculpin were first caught in low numbers in 1996 and by the early 2000s there were indications of population recovery . we updated the status of lake ontario deepwater sculpin through 2016 to inform resource management and conservation . our data set was comprised of 8431 bottom trawls sampled from 1996 to 2016 , in u . s . and canadian waters spanning depths from 5 to 225
) . longer wavelengths ( ≥ 625 nm ) were rapidly attenuated and not detectable deeper than 40 m . deepwater sculpin displayed broader sensitivity between 475 to 550 nm than the other two species , but outside of these wavelengths , all fishes had similar spectral sensitivity curves .
. . . mysis relicta and diporeia spp . are generally the two main prey eaten by deepwater sculpin in the great lakes ( scott & crossman 1973 ; wojcik et al . 1986 ; selgeby 1998 ; hondorp et al . 2005 ; o ' brien et al . 2009 ) . recently , abundances of one of the main prey for the deepwater sculpin , diporeia spp . , have undergone dramatic declines in the laurentian great lakes ( nalepa et al . 2007nalepa et al . , 2009 watkins et al . 2007 ) . . . .
deepwater sculpin have been known to reach 9 inches ( 23 cm ) in length , although the average is between 2 and 5 inches ( 5 to 10 cm ) . the body is slender with a large flattened head and blunt snout with a large mouth . eyes are set close together on top of the flattened head . there are four preopercular spines , the two upper ones so close together as to be mistaken as one ( brandt , 1986 ) . there are two dorsal fins , the second significantly larger than the first . in mature males , this second dorsal fin often overlaps the base of the caudal fin , and is one of the distinguishing characteristics of deepwater sculpin ( page et al . , 1991 ) . although deepwater sculpin have no scales , they do have prickles on top of the body .
are limited to north america . once abundant in the great lakes and most deep lakes of canada ( especially nipigon in ontario , great slave in manitoba , waterton in alberta , and great bear in the northwest territories ) , the geographic range of deepwater sculpin is rapidly shrinking .
our work provides the first daily ration model for slimy and deepwater sculpin and reveals that as diporeia have declined , each sculpin species supplemented its diet by eating more of other prey . an unexpected result was that both species appeared to be eating as much , if not more today ( as percent bodyweight ) than in the past when decreases in diporeia had yet to occur . as each sculpin species found different prey types to eat in the absence of diporeia , results suggest they can co - exist where spatial overlap occurs despite a lack of important prey .
fish ages are determined by counting the
rings
on bones in their ears ( otoliths ) . like tree rings , these rings represent years of growth . according to data collected in the summer of 1973 , deepwater sculpin in the great lakes live as long as seven years .
madenjian cp , bunnell db ( 2008 ) depth distribution dynamics of the sculpin community in lake michigan . t am fish soc 137 : 1346–1357
deepwater sculpin myoxocephalus thompsonii are an important component of great lake ' s offshore benthic food webs . recent declines in deepwater sculpin abundance and changes in bathymetric distribution may be associated with changes in the deepwater food web of lake huron , particularly , decreased abundance of benthic invertebrates such as diporeia . to assess how deepwater sculpins have responded to recent changes , we examined a fifteen - year time series of spatial and temporal patterns in abundance as well as the diets of fish collected in bottom trawls during fall of 2003 , 2004 , and 2005 . during 1992–2007 , deepwater sculpin abundance declined on a lake - wide scale but the decline in abundance at shallower depths and in the southern portion of lake huron was more pronounced . of the 534 fish examined for diet analysis , 97 % had food in the stomach . mysis , diporeia , and chironomidae were consumed frequently , while sphaerid clams , ostracods , fish eggs , and small fish were found in only low numbers . we found an inverse relationship between prevalence of mysis and diporeia in diets that reflected geographic and temporal trends in abundance of these invertebrates in lake huron . because deepwater sculpins are an important trophic link in offshore benthic food webs , declines in population abundance and changes in distribution may cascade throughout the food web and impede fish community restoration goals .
deepwater sculpin myoxocephalus thompsonii are an important component of great lake ' s offshore benthic food webs . recent declines in deepwater sculpin abundance and changes in bathymetric distribution may be associated with changes in the deepwater food web of lake huron , particularly , decreased abundance of benthic invertebrates such as diporeia . to assess how deepwater sculpins have responded to recent changes , we examined a fifteen - year time series of spatial and temporal patterns in abundance as well as the diets of fish collected in bottom trawls during fall of 2003 , 2004 , and 2005 . during 1992–2007 , deepwater sculpin abundance declined on a lake - wide scale but the decline in abundance at shallower depths and in the southern portion of lake huron was more pronounced . of the 534 fish examined for diet analysis , 97 % had food in the stomach . mysis , diporeia , and chironomidae were consumed frequently , while sphaerid clams , ostracods , fish eggs , and small fish were found in only low numbers . we found an inverse relationship between prevalence of mysis and diporeia in diets that reflected geographic and temporal trends in abundance of these invertebrates in lake huron . because deepwater sculpins are an important trophic link in offshore benthic food webs , declines in population abundance and changes in distribution may cascade throughout the food web and impede fish community restoration goals .
the deepwater sculpin is presently listed as a species of special concern ( soc ) in mt due to its limited distribution ( s3 , vulnerable - meaning they are at risk for potential declines in population , range or habitat even though they are abundant in some areas ) ( mnhp 2011 ) .
the slimy sculpin can be distinguished by its pair of free and independent pelvic fins and its lack of scales . see also similar species information .
the diel vertical migrating ( dvm ) zooplankton , mysis diluviana , is the primary conduit for energy flow from benthic waters to the surface , as it feeds diurnally on benthic detritus and switches to midwater phytoplankton and zooplankton during its nightly ascent [ 6 , 7 ] . two planktivorous fish , deepwater sculpin and kiyi , prey primarily on the mysis , with the deepwater sculpin also consuming benthic amphipods ( diporea spp . ) [ 3 , 8 ] . the siscowet is the most abundant piscivore in the lake [ 2 , 9 ] and its feeding habits are dictated by diurnal vertical migrations of the planktivores [ 7 ] . during the day , the siscowet remain in deepwater ( > 140 m ) and prey primarily on benthic sculpin , while at night , they vertically migrate to consume kiyi which are following the migration of mysis [ 2 , 3 , 4 , 10 , 11 ] .
geffen , a . j . and r d . m . nash . 1992 . the life - history strategy of deepwater sculpin , myoxocephalus thompsoni ( girard ) , in lake michigan : dispersal and settlement patterns during the first year of life . journal of fish biology 41 : 101 - 110 .
visual spectral sensitivity curves for dark adapted siscowet , kiyi , and deepwater sculpin were constructed using erg responses to monochromatic light of different wavelengths . all three fishes exhibited maximum sensitivity at 525 nm with relatively broad sensitivity from 500 to 550 nm and markedly decreasing sensitivity to wavelengths < 475 nm and > 575 nm (
the deepwater water sculpin proved exceptionally sensitive to light stimuli with over 3 minutes required between flashes to obtain successive equal amplitude ergs . direct interspecific comparisons of maximum visual sensitivity are not possible using the erg as eye size and electrode position can influence b - wave amplitudes between fishes , however , the long interflash interval needed to regain full erg amplitudes indicates that the deepwater sculpin maybe the most sensitive of the three species . this is consistent with its deepwater benthic adult phase which places it in a low intensity light environment . the models show sufficient visual sensitivity to potentially mediate predator - prey interactions throughout the majority of its range . as the deepwater sculpin is the preferred prey of siscowet , its greater visual sensitivity may allow it to detect the siscowet at sufficient range to evade predation . its benthic position provides an additional advantage as it can discern the predator silhouettes illuminated by the downwelling light while the siscowet faces the more difficult task of visualizing benthic prey against a dark background . although at its average depth insufficient light is available for visual function at night , its main predator undergoes dvm and therefore vision may not be necessary during this time .
deepwater sculpin were the most susceptible to short interflash intervals and needed a minimum of 190 seconds between flashes to avoid transient “bleaching” . lake trout required 80 seconds , while 30 second interflash intervals were sufficient for kiyi to recover full sensitivity . the dark adapted retinas displayed a strong b - wave and no evidence of an a - wave (
. . . benthivore diet studies in large aquatic ecosystems have indicated that both regional and temporal variation can be important to incorporate ( e . g . , garrison and link 2000b ; byron and link 2010 ) . our glm results revealed that benthivore diets varied more across sites than by day of year , which was consistent with previous reports that spatial variability in sculpin diets was likely driven by differential availability of prey species across sites ( hondorp et al . 2005 ; o ' brien et al . 2009 ) . furthermore , other studies that have sampled sculpin diets across multiple seasons have revealed minimal variation in diet composition except for higher occurrences of fish eggs in the diets of slimy sculpin during spring and autumn and in the diets of deepwater sculpin during autumn ( wells 1980 ; kraft and kitchell 1986 ; wojcik et al . 1986 ) . . . .
no significant specific threats have been identified . the current distribution is static because the species does not move between lakes , making it vulnerable to local extirpation should current lake habitats become eutrophied or disturbed . deepwater sculpin were not detected in two canadian lakes now relatively eutrophic or mesotrophic , but which were previously occupied ( sheldon et al . 2008 ) .
over the last decade and a half , populations of this prey , called
diporeia ,
crashed in lake michigan . fishery managers feared that without this key prey , slimy and deepwater sculpin would have less to eat and their health could suffer . in addition , their role as important invertebrate predators and prey for native fishes could be affected .
the general method for determining age has been to count the annual ‘rings’ on the otolith . according to data collected in the summer of 1973 , the maximum age for deepwater sculpin in the great lakes was seven years . more recent research suggests that alternating clear and dark bands on the otolith reflect rapid growth during the summer and much slower growth during the winter .
roseman ef , riley sc ( 2009 ) biomass of deepwater demersal forage fishes in lake huron , 1994–2007 : implications for offshore predators . aquat ecosyst health manag 12 ( 1 ) : 29–36
results of this study ,
gastric evacuation rate , index of fullness , and daily ration of lake michigan slimy ( cottus cognatus ) and deepwater sculpin ( myoxocephalus thompsonii ) ,
are reported by by justin mychek - londer and david ( bo ) bunnell in volume 39 , no . 2 , of the journal of great lakes research , published by elsevier , 2013 .
monitoring changes in diets of fish is essential to understanding how food web dynamics respond to changes in native prey abundances . in the great lakes , diporeia , a benthic macroinvertebrate and primary food of native benthivores , declined following the introduction of invasive dreissena mussels and these changes were reflected in fish diets . we examined the diets of deepwater sculpin . . . [ show full abstract ]
from 1942 to 1972 , no deepwater sculpin were captured in lake ontario so far as is known . between 1972 and 2002 , only six have been caught there , despite continued government mandated trawls aimed at determining the extent of their extirpation from the great lakes . all six were caught in canadian waters , three in 1972 and three in 1996 ( black et al . 1981 ) .
the deepwater sculpin spawns year round and is usually found in cold water - 40 degrees f . or less . it spawns during the winter in lake michigan and during the summer and early fall in canada . in lake huron , scientists determined that hatching occurs after ice breakup . the fish feeds on small crustaceans ( primarily mysis and pontoporeia ) and aquatic insects that live on the bottom .
slimy and deepwater sculpin occupy an important role in the great lakes food web because they eat invertebrates and fish eggs and are themselves eaten by predators such as lake trout . because of this role , any negative impacts on sculpin populations have the potential to adversely impact the entire foodweb ,
says justin mychek - londer , a scientific contractor at the usgs great lakes science center .
accurate estimates of consumption by sculpins will help address concerns such as whether they’re eating less today than in the past and what the potential effects of their predation on native fish eggs may be .
due to their role as key forage items for lake trout and burbot and because m . relicta and p . hoyi are their main food sources , deepwater sculpin are thought to be responsible for facilitating the majority of the energy movement from benthic organisms to higher trophic levels . this obscure but critical role is likely to have far ranging influences on the overall productivity of the entire great lakes ecosystem .
the maximal depth at which sufficient downwelling irradiance is available to elicit an erg under full sun conditions is plotted versus depth ( m ) for kiyi ( black circles ) , siscowet ( white circles ) , and deepwater sculpin ( black triangles ) for ( a ) spring / summer ( k par = 0 . 1 ) and ( b ) fall ( k par = 0 . 3 ) conditions in lake superior .
the maximum depth at which sufficient downwelling irradiance is available to elicit an erg under full moon conditions is plotted versus depth ( m ) for kiyi ( black circles ) , siscowet ( white circles ) , and deepwater sculpin ( black triangles ) for ( a ) spring / summer ( k par = 0 . 1 ) and ( b ) fall ( k par = 0 . 3 ) conditions in lake superior .
the predator - prey interactions in the offshore food web of lake superior have been well documented , but the sensory systems mediating these interactions remain unknown . the deepwater sculpin , ( myoxocephalus thompsoni ) , siscowet ( salvelinus namaycush siscowet ) , and kiyi ( coregonus kiyi ) inhabit low light level environments . to investigate the potential role of vision in predator - prey interactions , electroretinography was used to determine visual sensitivity for each species . spectral sensitivity curves revealed peak sensitivity at 525 nm for each species which closely corresponds to the prevalent downwelling light spectrum at depth . to determine if sufficient light was available to mediate predator - prey interactions , visual sensitivity was correlated with the intensity of downwelling light in lake superior to construct visual depth profiles for each species . sufficient daytime irradiance exists for visual interactions to approximately 325 m for siscowet and kiyi and 355 m for the deepwater sculpin during summer months . under full moon conditions , sufficient irradiance exists to elicit erg response to light available at approximately 30 m for the siscowet and kiyi and 45 m for the deepwater sculpin . visual interactions are therefore possible at the depths and times when these organisms overlap in the water column indicating that vision may play a far greater role at depth in deep freshwater lakes than had been previously documented .
. . . which appear to be related to the expansion of dreissenid mussels ( nalepa et al . , 2009nalepa et al . , , 2010 ) . these threats may help explain recent shifts in depth distributions ( madenjian et al . , 2012 ) , food habits ( mychek - londer et al . , 2013 ; o ' brien et al . , 2009 ; owens and dittman , 2003 ) and energy densities ( hondorp et al . , 2005 ; pothoven et al . , 2011 ) of slimy and deepwater sculpin in the great lakes . improved understanding of consumption by native sculpins may improve our understanding of how they contribute to food web dynamics , and could aid in management of diminished deepwater sculpin populations in lakes ontario and erie ( lantry et al . , 2007 ; owens and dittman , 2003 ; roseman et al . , 1998 ) . . . .
the deepwater sculpin , new york ' s largest sculpin , ranges from 2 to 4 . 7 inches in length ; however , one lake ontario specimen measured 9 . 2 inches . the fish has a long , tapered body , a blunt snout and a flat head . unlike other sculpin species , the deepwater has four preopercular ( cheekbone ) spines , with the upper two spines close enough to appear as one large spine . gill membranes join at a sharp angle and are free from the isthmus ( or breast ) . there are two widely separated dorsal ( back ) fins . the second dorsal fin has a long base and long fin rays and is often enlarged on males . the caudal ( tail ) fin is square , the pelvic ( bottom rear ) fins are shaped like paddles and the pectoral ( front side ) fins are shaped like fans . the body has no scales , but is prickled on top . it is generally grey - brown in color with a lighter underside . the back and sides are speckled and there are thin , dark saddle - like marks on the back .
all fishes were dark adapted for 30 minutes prior to testing . a 200 ms flash of monochromatic light of different wavelengths was used to elicit the erg . wavelengths from 400 to 700 nm at 25 nm intervals were used as the stimulus with the presentation order randomly determined . stimulus intervals were determined for each species by presenting consecutive flashes to control fish to determine the delay required to produce the same response amplitude to minimize photobleaching . interflash intervals ranged from 30 s for the kiyi to 190 s for the deepwater sculpin . experiments were attempted within the same time period each day to minimize intraspecfic circadian differences . deepwater sculpin and siscowet experiments were initiated between 1030 and 1530 . however , due to the compromised physiology of the kiyi , experiments were initiated as soon as fish were transported to the lab which resulted in trials being conducted between 0025 and 1030 within the first week following the trawl .
deepwater sculpin can begin to reproduce when they reach 3 years old . it is thought that they breed throughout the year , with breeding in late fall and winter in the great lakes and in summer and early fall in canadian lakes . females lay an average of 481 eggs each time they breed , with the largest females laying the most eggs . in the great lakes the eggs hatch at the same time that the ice on the lakes begins to break up .
. . . n / a = not available . occurred since the diporeia decline have indicated that the diets of both sculpin species can be dominated by mysis , while diporeia will still be consumed in the regions where it remains present ( e . g . , french et al . , 2010 ; o ' brien et al . , 2009 ) . the only major difference between our results and previous studies was that slimy sculpin diets were more diverse ( but see ) . . . .
the deepwater sculpin appears to remain near the bottom in deep oligotrophic glacial lakes , but habitat descriptions are limited because of the difficulty of capture or detection ; the record depth is about 366 m ( 1200 ft ) in both great bear lake and lake superior ( scott and crossman 1973 ) . all lakes occupied in a 2004 survey had relatively low nutrient concentrations and low biological production rates , maximum water depths exceeding 35 m ( 115 ft ) and benthic water temperatures below 8 c during summer . ( sheldon et al . 2008 ) .
all species survived trawling and transport to the university of minnesota duluth . despite remediation of gas bladder expansion in the kiyi , fish continued to exhibit buoyancy problems and survived less than a week in captivity . therefore , all kiyi were tested within 4 days of capture . although siscowet displayed minor buoyancy problems , these quickly disappeared within one week of capture and both the siscowet and sculpin have been maintained over a year in captivity indicating no long term physiological effects of trawling . siscowet were tested within 3 weeks of capture and sculpin within 2 months of capture .
due to their benthic habitat , deepwater sculpin spend their adult lives in complete darkness where the temperature ranges between 3 and 6 degrees celsius . at this depth , the bottom substrate is fine particulate matter , mud and clays of a uniform size . when they were much more plentiful , they could also be found on substrates consisting of combinations of sand , silt , clay and mud intermixed with rocks , coal and cinders . during one study in 1952 , they were found in the waters off munising , michigan , on thick beds of aquatic vegetation ( jacoby 1953 ) .
size increase is greatest in the first year . during the second and third years of life , size increase is typically three - fifths that of the first year . in successive years , the length increase was less than two - fifths that of the first year . on the other hand , weight gain is inversely related to length increase . deepwater sculpin put on the least weight in the first year , despite the greatest gain in length . in successive years , as elongation slows , weight gain increases ( selgeby , 1988 ) . the largest fish tend to be the oldest .
we thank the crew of the r / v kiyi for their assistance in catching the deep water fishes for this project . for help on the protocol for trawling the deepwater fish and limiting mortality in the lab , we thank owen gorman and for assistance with spectral sensitivity calculations we thank tamara frank .
deepwater sculpin are the number one prey item for lake trout ( salvelinus namaycush ) , a once widely available , commercially harvested fish found in all the great lakes . although a concerted effort has been made since 1950 to restore lake trout populations to the great lakes , success has been spotty and limited . natural reproduction of lake trout is currently occurring on a widespread basis only in lake superior . in lakes huron , michigan and ontario , only limited natural reproduction has occurred . of these three , only in lake huron do the larval fish survive into adulthood ( usgs , 2001 ) .
in cool streams and shallow margins of the great lakes . in streams they eat aquatic insect larvae and sideswimmers . in lakes , copepods , waterfleas , leeches , and algae are added . occasionally , fish eggs and even small fish are found in mottled sculpin stomachs . length to 13 cm .
although they are relatively abundant in some lakes compared to other fishes and even recent invaders like round goby , little is known about the biology of these sculpin species . in particular , estimates of daily consumption ( or how much a fish eats in a day ) do not exist for these species .
deepwater sculpin are the number one prey item for lake trout , which was once one of the most important fish in the great lakes . they were fished on a large scale and were very important economically . overfishing and the introduction of non - native sea lampreys caused a huge decline in lake trout populations . since 1950 many agencies have been trying to restore lake trout populations to the great lakes , but without much success . lake trout are currently only doing well in lake superior . they are reproducing in the other great lakes but only in lake superior and lake huron are young lake trout surviving into adulthood .
the fishes that comprise the deep water food web spend the majority of their time in a low light level environment . following a pelagic larval stage , deepwater sculpin transition to the benthos and remain at depths ranging from 15 to 407 m [ 13 , 14 , 15 , 16 ] with the majority of the lake superior population inhabiting depths below 70 m . in contrast , siscowet and kiyi are midwater water fish that undergo diel vertical migration ( dvm ) with siscowet depth distributions ranging from the surface ( night ) to 407 m ( day ) , while kiyi are found between 25 m ( night ) and 325 m ( day ) [ 7 , 10 , 17 ] . therefore all three species spend the majority of their life in light limited environments .
deepwater sculpins are found in north american lakes of the hudson bay drainages from the northwestern territories of canada to the great lakes drainages of the eastern united states , ontario and quebec that have glacial origins or have been affected during the last glacial period . in montana , one lake in glacier national park ( upper waterton lake ) has been identified as an occurrence site , but the fish has been taken from the lake only in the canadian portion . total documented global range includes , at most , 63 lakes .
, 1981 ) . the average number of eggs found in the ovaries of ripe females ( females who are just about to lay eggs ) is 481 . as in other aspects of sculpin life , size does matter and the largest females have the greatest numbers of eggs . eggs range in size from 1 . 5 to 2 . 2 mm ( jacoby , 1953 ) . in the great lakes the eggs hatch at the same time that the ice on the lakes begins to break up .
the deepwater sculpin is one of the most poorly known native freshwater fishes in north america ( parker 1988 ) . it reaches 23 cm ( 9 . 0 in . ) in length , but is usually smaller ; the first two collected in upper waterton lake ( mcallister and ward 1972 ) were 2 . 7 and 4 . 8 cm ( 1 . 1 and 1 . 9 in . ) standard length . there is a large gap between the two dorsal fins , and a series of bony plates along the lateral line . the head is extremely wide and flat , and the mouth extends to below the eye . large diskline scales are present on the back and sides above the lateral line . large males have a very large 2nd - dorsal and pectoral fins . the lateral line is complete ( in western populations ) . there are four preopercular spines , the upper two large and directed upward , the lower two directed downward . overall appearance includes dark brown to green mottling , often with 4 - 7 green saddles , on a gray - brown back and sides , with a whitish belly ( page and burr 1991 ) .
. . . most sculpin species are important links between benthic invertebrate and piscivorous food webs ( sierzen et al . 2003 ; o ' brien et al . 2009 ; jacobs et al . 2010 ) . in northern lakes , including alaska and the nwt , their primary predators include burbot ( lota lota ) and lake trout ( salvelinus namaycush ; hanson et al . 1992 ; lienesch et al . 2005 ; keyse et al . 2007 ) ; these fish species were also identified as predators of sculpins in the great lakes ( brandt 1986b ) . . . .
. . . sculpins are an important link between benthic and pelagic food webs ( sierzen et al . 2003 ; o ' brien et al . 2009 ; jacobs et al . 2010 ) . in the past , sculpin species have been labelled as obligate benthivores ( brandt 1986a ) , but recent evidence of cannibalism , piscivory , and oophagy ( i . e . , egg consumption ) , as well as stable isotope evidence of a pelagic diet has been reported suggesting that they are facultative benthivores ( cuker et al . 1992 ; miller et al . 1992 ; mirza and chivers 2002 ; black et al . 2003 ; pfister 2003 ; janssen et al . 2006 ) . . . .