elysia catulus is a small species of sea slug , a marine gastropod mollusc in the family plakobranchidae .

this sea slug resembles a nudibranch , but it is not closely related to that order of gastropods , instead it is a sacoglossan .

the specific name " catulus " comes from the greek and means " little cat " , referring to the superficial resemblance that the head of this slug bears to the head of a cat .

elysia catulus

what type of species is elysia catulus ? below , you will find the taxonomic groups the elysia catulus species belongs to .
which photographers have photos of elysia catulus species ? below , you will find the list of underwater photographers and their photos of the marine species elysia catulus .
how to identify elysia catulus marine species ? below , you will find the list of main identification criteria and physical characteristics of marine species elysia catulus . for each identification criteria , the corresponding physical characteristics of marine species elysia catulus are marked in green .
where is elysia catulus found in the world ? below , you will find the list and a world map of the geographic distribution where the marine species elysia catulus can be found .
species elysia bedeckta macfarland , 1966 accepted as elysia hedgpethi er . marcus , 1961
species elysia purchoni thompson , 1977 accepted as elysia canguzua er . marcus , 1955
elysia bedeckta macfarland , 1966 : synonym of elysia hedgpethi er . marcus , 1961
rudman wb . 2004 . elysia catulus gould 1870 . species profile from sea slug forum . australian museum , sydney . available online .
the seagrass elysia , elysia serca . photo sea slug forum . photographer marina poddubetskaia .
species elysia eugeniae ortea & espinosa , 2002 accepted as elysia canguzua er . marcus , 1955
species elysia pruvotfolae er . marcus , 1957 accepted as elysia velutinus pruvot - fol , 1947
jensen ( 1983a ) notes that the shape of the radular teeth of e . serca is indistinguishable from that of another seagrass - feeding ascoglossan , elysia catulus . the author suggests that e . serca may be an ecotype or subspecies of e . catulus . in light of this , relevant information from the literature pertaining to e . catulus is included here along with that for e . serca .
species elysia zemi krug , vendetti & valdés , 2016 accepted as elysia cauze er . marcus , 1957
species elysia minuta sars m . , 1835 accepted as elysia viridis ( montagu , 1804 ) ( synonym )
species elysia pagenstecheri marcus ev . , 1982 accepted as elysia viridis ( montagu , 1804 ) ( synonym )
species elysia clena er . marcus & ev . marcus , 1970 accepted as elysia serca er . marcus , 1955
species elysia tuca ev . marcus & er . marcus , 1967 accepted as elysia velutinus pruvot - fol , 1947
placobranchus catulus - from a drawing by toppan of an east boston specimen . gould , 1870 : plate xvii . fig . 249 .
species elysia annedupontae ortea , caballer , moro & espinosa , 2005 accepted as elysia papillosa a . e . verrill , 1901
jensen suggests that elysia catulus ( gould , 1870 ) which is found on the atalntic coast of nth america , north of florida , and feeds on the sea grass zostera , is possibly an older synonym .
while preparing marina ' s messages [ 12391 , # 12392 ] i tried , without success , to find a good illustration or photo of elysia catulus to compare with e . serca . i have included here a copy of the painting in gould ' s description of e . catulus alongside on of marina pod specimens for e . serca from the bahamas . the whitish markings on e . catulus seem to be identical to the markings on some of marina ' s animals even though the background colour is very variable . other authors have suggested that there is more melanin in northern populations of ' e . catulus ' but some of marina ' s animals show plenty of melanin in the bahamas . i would strongly agree with kathe jensen ' s suggestion that e . serca and e . catulus are the same species .
egg diameters in connecticut e . catulus averaged approximately 75µm . using the criteria of thompson ( 1967 ) , clark ( 1975 ) describes e . catulus as having type i development , characterized as having relatively small ova , short hatching times ( 2 - 28 days ) , and a long planktonic larval phase .
elysia clena ( marcus and marcus 1970 ) is considered by jensen ( 1982 ) to be a junior synonym . elysia catulus ( gould 1870 ) , currently recognized as a valid species with a more northern distribution than c . serca , may actually be c . serca with a different name .
elysia cauze scops ev . marcus & er . marcus , 1967 : synonym of elysia scops ev . marcus & er . marcus , 1967
elysia catulus exhibits significantly more thermal tolerance . animals in connecticut ' s mystic river estuary persist in habitats that exceed 27°c in the summer and are susceptible to ice formation in winter ( clark 1975 ) . clark ( 1975 ) reports a behavioral response of e . catulus to the onset of cold temperatures in which individuals seek the shelter of the crevice within the fascicle binding adjacent seagrass leaves .
clark ( 1975 ) suggests that the feeding strategy ( cell piercing ) of elysia catulus may have allowed the animal to serve as a vector in the transmission of the zostera wasting disease that decimated zostera seagrass populations in the early 1930s . the author notes , however , that the actual act of feeding causes negligible damage to seagrasses , due to the relatively small size of e . catulus populations .
elysia serca is a subtropical to tropical species , occurring in the western atlantic from florida to brazil ( rudman 2004a ) . elysia catulus , a possible northern morph with older synonymy , is distributed along the atlantic coast of north america from nova scotia to south carolina ( rudman 2004b ) . clark ( 1975 ) notes that the larvae of most nudibranchiate molluscs from southern new england waters , including e . catulus , are allochthonously produced , not the result of endemic reproduction .
thanks marina , these little sea grass - eating species are a very interesting sacoglossan adaptation . i agree with kathe ' s synonymy of e . serca and e . clena but can ' t see any reason why the third species , e . catulus isn ' t included as well . elysia chlorotica would seem to have a similar geographical distribution down the atlantic coast of the americas so it would not be that strange from the elysia catulus to do the same . best wishes bill rudman
» species elysia ( elysiopterus ) verrilli pruvot - fol , 1946 accepted as elysia velutinus pruvot - fol , 1947 ( invalid : junior homonym of elysia verrilli thiele , 1931 ; e . velutinus and e . pruvotfolae are replacerment names )
re : elysia serca from : kathe r . jensen , march 22 , 2004
cuttersgoose commented on
elysia subornata a . e . verrill , 1901
:
no evidence of post - fertilization investment parental investment for elysia crispata has been noted .
it is a bit hard to make out much detail in your photo , but if you are familiar with the shape of elysia chlorotica then i guess we are not looking at a flatworm infestation . elysia catulus is the most likely identification , and just because it has not been reported north of nova scotia certainly does not rule out the likelihood of it being found in newfoundland .
species elysia ratna er . marcus , 1965 accepted as thuridilla gracilis ( risbec , 1928 )
here ' s a great video of a juvenile elysia chlorotica feeding for the first time .
sea slug elysia chlorotica . proceedings of the national academy of sciences 105 : 17867 - 17871 .
thanks marina , as i said before , it seems very likely that e . catulus is the oldest name for a single species which lievs all down the atlantic coast of nth and sth america . best wishes bill rudman
information on the lifespan of elysia serca in florida is lacking . the lifespan of connecticut elysia catulus individuals appears to be just under one year . newly settled individuals arriving in late august and early september , growing to maturity over the next several months , producing eggs in june and july , and disappearing ( apparently due too mortality ) by late july just prior to the next juvenile settlement event ( clark 1975 ) .
clark ( 1975 ) reports elysia catulus is one of very few nudibranchiate molluscs present in abundance in the mystic river estuary , ct , throughout all or most of the year . for all months except late summer , the author was able to collect more than 50 individuals per hour and noted its presence virtually wherever zostera marina occurred . as with most nudibranchiate molluscs , the sudden appearance of large e . catulus populations is due to the arrival of large numbers of settling larvae followed by the rapid growth of newly - settled individuals to visible size .
clark ( 1975 ) confirms that mystic river estuary e . catulus populations lived on and consumed the seagrass zostera marina . the author notes that this is the first ever report of a sacoglossan which feeds on a spermatophyte plant .
now i have finally got around to answering the elysia serca / catulus questions [ # 12446 ] . there was one of my old papers that i could not locate in all my old piles of reprints and it has been more than 20 years since i worked with these animals , so i have to refresh my memory .
elysia serca is a small elysiid , attaining a total length of about 8 mm ( rudman 2004 ) .
photo : left : placobranchus catulus ' east boston specimen ' . gould , 1870 . pl . 17 , fig . 249 . right : great exuma , bahamas , western atlantic . depth : 1m . length : 4mm . february 03 , 2004 . photo : marina poddubetskaia
elysia serca is one of 11 elysia species reported from shallow marine environments in florida ( camp et al . 1998 ) . at least eight elysia congeners are known to occur in the irl ( e . canguzua , e . chlorotica , e . evelinae , e . ornata , e . patina , e . serca , e . subornata , e . tuca ) .
although cryptic in its occurrence , elysia serca may well be found throughout the seagrass beds of the indian river lagoon system .
species elysia picta a . e . verrill , 1901 accepted as thuridilla picta ( a . e . verrill , 1901 )
elysia picta a . e . verrill , 1901 : synonym of thuridilla picta ( a . e . verrill , 1901 )
larval settlement in connecticut e . catulus populations occurs in late august and early september . newly settled individuals typically exploit the safety of ( inrolled is this a word ? ) zostera leaf margins , and older / larger animals typically occupy the exposed flat leaf surfaces ( clark 1975 ) .
i decided to take a quick picture to see what they were . the shape of the head and body reminded me a lot of the elysia chlorotica i was working with in new brunswick . i see that newfoundland is way beyond the range of e . serca , and even past the range of e . catulus ( if they are indeed separate species ) . are there other candidates i ' m not thinking of ?
species elysia duis ev . marcus & er . marcus , 1967 accepted as thuridilla picta ( a . e . verrill , 1901 )
rudman wb . 2004 . elysia serca marcus , 1955 . species profile from sea slug forum . australian museum , sydney . available online .
international kleptoplasty champion ( 2000 - 2013 ) : elysia chlorotica . photo credit : patrick krug cataloging diversity in the sacoglossa lifedesk . wikimedia commons
elysia serca is strictly associated with subtropical to tropical seagrass habitats . the seagrasses act as both living space / refuge and food source for this animal .
the distinctive physical appearance of e . tuca ( see above ) combined with the strong association of all members of the genus with their respective preferred food sources ( seagrass in the case of e . serca ) , should be sufficient to allow differentiation of the seagrass elysia from co - occurring elysia species .
hosoe k . 1956 . notas biologicas sobre elysia serca marcus , 1955 . universidade de sao paulo contribuicoes avulsas do instituto oceanografico 2 : 1 - 6 .
dear bill , to complete my previous message [ # 12391 ] about elysia serca , here are the photos of the dark colour form of this species .
nomenclature the name elysia was established in synonymy of notarchus but it is available under iczn art . 11 . 6 . 1 because it was used as . . .
capman , b . 2002 .
lettuce sea slug - elysia crispata ( tridachia crispata )
( on - line ) . accessed june 06 , 2011 at urltoken .
species elysia bayeri er . marcus , 1965 accepted as thuridilla bayeri ( er . marcus , 1965 ) accepted as thuridilla gracilis ( risbec , 1928 ) ( original combination )
the subtropical / tropical elysia serca is restricted to warm waters from florida to brazil . low water temperature is likely the key factor restricting the northern distributional limits of the species .
jensen kr . 1982 . occurrence of elysia serca marcus in florida , with notes on the synonymy and biology of the species . journal of conchology 31 : 87 - 94 .
kathe jensen wrote :
there is a slight possibility that the darker coloured specimens are e . catulus which is found further north ( connecticutt to chesapeake bay ) . this species also feeds on seagrasses , and is very similar to e . serca ( and may actually be the same species too ) . . . the dark pigmentation is probably one gene , which is either present or not .
( of elysia ( elysiopterus ) pruvot - fol , 1946 ) krug p . j . , vendetti j . e . & valdés á . ( 2016 ) . molecular and morphological systematics of elysia risso , 1818 ( heterobranchia : sacoglossa ) from the caribbean region . zootaxa . 4148 ( 1 ) : 1 - 137 . , available online at urltoken [ details ]
jensen , k . r . 1983 . further notes on the ecology and systematics of elysia serca marcus ( opisthobranchia , ascoglossa ) . journal of molluscan studies 49 : 69 - 72 .
rudman , w . 2006 .
elysia crispata ( morch , 1863 ) . .
( on - line ) . sea slug forum . accessed june 10 , 2011 at urltoken .
to cite this page : noto , v . and k . queenan 2011 .
elysia crispata
( on - line ) , animal diversity web . accessed july 09 , 2018 at urltoken
i wrote to kathe jensen to have her opinion . her answer was very interesting and full . here is an extract : i think i have an id for elysia sp . 1 and 2 . in fact i am pretty sure they are the same species . . . many years ago i synonymized 2 of marcus ' species , elysia serca and e . clena , and this is what i think you have here . they feed on seagrasses , and i think that the seagrass on your pictures is halodule wrightii . so the name should be elysia serca . . .
while a review of the relevant literature suggests a lack of extraordinary tolerance to salinity fluctuation , the presence of elysia serca in habitats of seasonally varying salinity suggest the species is at least somewhat euryhaline .
nomenclature the name elysia was established in synonymy of notarchus but it is available under iczn art . 11 . 6 . 1 because it was used as a valid name before 1960 . [ details ]
dear bill , here are the photos of the alga on which i found the pale and dark elysia serca [ messages # 12391 , # 12392 ] . kathe jensen identified it as halodule wrightii .
although several sacoglossan molluscs are known to be capable of kleptoplasty ( the retention of functional chloroplasts derived from typically macroalgal food sources ) , functional chloroplasts have thus far not been found in either e . serca or e . catulus ( clark et al . 1990 ) . this may be due to the unsuitability of seagrass chloroplasts for kleptoplastic retention compared to those from macroalgae such as caulerpa spp . , halimeda spp . , and other forms that apparently lend themselves to kleptoplasty .
• jensen , k . r . ( 1983 ) further note on the ecology and systematics of elysia serca marcus ( opisthobranchia , ascoglossa ) . journal of molluscan studies , suppl . 12a : 69 - 72 .
the teeth of e . serca / catulus are rather strange in having a very tall base . i think that this is because they need to penetrate more than one cell wall at a time on a flat substrate . they prefer halophila because this seagrass has only two layers of cells , both containing chloroplasts . the pharynx is shaped similar to that of elysiella pusilla with a very thick layer of muscles surrounding the ventral limb of the radula . this would give added force to the leading radular tooth .
chlerogella elysia is superficially similar to c . terpsichore but differs most notably in the absence of amber on the clypeus , the shorter malar space , presence of distinct fluorescence on the mesosoma and head , and male sterna and terminalia .
dear bill , in the southern bahamas i discovered a new [ to me ] elysia species . all the specimens were tiny and i could clearly separate them into a pale or a dark colour form . i called them elysia sp . 1 and sp . 2 , just in case they could be two different species . but they were found in one same place and they seem to feed on the same alga ( see my next message [ # 12392 ] ) .
“ elysia cf . marginata sp . 4
, nick - named
white lines
, is one of 4 cryptic species in the elysia marginata complex recently documented from the indo - pacific using a combination of molecular , morphological , and developmental characters . found on the green algal genus bryopsis , species in this complex are sometimes termed
e . ornata
, which is a distinct caribbean species , or
e . grandifolia
, an indo - pacific taxon with no definitive characteristics .
“ elysia cf . marginata sp . 3
, nick - named
dark pigment
, is one of 4 cryptic species in the elysia marginata complex recently documented from the indo - pacific using a combination of molecular , morphological , and developmental characters . found on the green algal genus bryopsis , the species in this complex are sometimes termed
e . ornata
, which is a distinct caribbean species , or
e . grandifolia
, an indo - pacific taxon with no definitive characteristics .
“ elysia cf . marginata sp . 2
, nick - named
red tips
, is one of 4 cryptic species in the elysia marginata complex recently documented from the indo - pacific using a combination of molecular , morphological , and developmental characters . found on the green algal genus bryopsis , the species in this complex are sometimes termed
e . ornata
, which is a distinct caribbean species , or
e . grandifolia
, an indo - pacific taxon with no definitive characteristics .
“ elysia cf . marginata sp . 1
, nick - named
3 siphons
, is one of 4 cryptic species in the elysia marginata complex recently documented from the indo - pacific using a combination of molecular , morphological , and developmental characters . found on the green algal genus bryopsis , the species in this complex are sometimes termed
e . ornata
, which is a distinct caribbean species , or
e . grandifolia
, an indo - pacific taxon with no definitive characteristics .
the seagrass elysia , elysia serca , is a small opisthobranch mollusc of the order sacoglossa . the body color is variable , ranging from green to dark brown . a characteristic pattern of dorsal whitish patches is also usually present , with one patch on the body at about the heart and two more located midway along the free edge of the parapodia . other smaller white spots may be present as well . relative to other elysiids , the head is proportionally larger and the parapodia are somewhat reduced ( rudman 2004a ) .
as far as i can find , e . catulus has only been reported to feed on the sea - grass zostera , which makes it almost unique amongst the sacoglossans . as is discussed elsewhere on the forum , e . serca is an extremely similar species from further south on the west atlantic coast and is probably the same species . interestingly it is reported to feed on a variety of sea - grasses and also ulva , which your animals are also apparently feeding on . it would be interesting to know if this snimal also occurs on zostera in newfoundland . perhaps it changes food seasonally ?
concerning the feeding of e . serca / catulus , marina ' s photo of the animal on halodule [ # 12446 ] illustrates very well the feeding track . halodule has very small epidermal cells and much bigger mesophyll cells . e . serca penetrates right through the epidermal cells and sucks cytoplasm from the mesophyll cells ( which have few chloroplasts - or none ? ) . also , they empty more than one epidermal cell for each tooth penetration - including some in front of the mouth . the dark purple / brownish track is the
emptied
cells ( which must still contain some sort of chemical that change colour when the chloroplast containing cytoplasm has been removed ) .
krug p . j . , vendetti j . e . & valdés á . ( 2016 ) . molecular and morphological systematics of elysia risso , 1818 ( heterobranchia : sacoglossa ) from the caribbean region . zootaxa . 4148 ( 1 ) : 1 - 137 . , available online at urltoken [ details ]
bouchet , p . ; gofas , s . ( 2010 ) . elysia risso , 1818 . in : bouchet , p . ; gofas , s . ; rosenberg , g . ( 2010 ) world marine mollusca database . accessed through : world register of marine species at urltoken on 2010 - 12 - 14
small elysiid reaching approximately 6mm in length . the body is heavily pigmented with black but the greenish tinge of the body contents can be seen on close examination . whitish marks form a regular pattern : there is an elongate one on the head between the rhinophores , and similar ones on each side of the head running across the eyes . there are up to three white patches at the edge of the parapodia , one at the front , one midway down , and sometimes a third at the back , where the parapodia runs into the posterior tip of the foot . this species feeds on the sea grass zostera and its name catulus [ little cat ] is a reference to its likeness to a small cat .
one of 4 cryptic species in the elysia marginata complex , all found on bryopsis spp . intra - specific mtdna clades can be up to 6 % divergent at the coi barcoding locus in this complex , whereas morphologically and developmentally distinct species are > 8 % divergent ( krug . et al . , in press ) .
despite the co - occurrence of several elysia congeners in the irl and elsewhere in florida , the dietary specializations particular to each species very likely preclude severe interspecific competition for food resources . the persistence of the species at relatively low overall density relative to the availablility of seagrass suggests that food availability is not a likely limiting resource .
( of elysiella bergh , 1871 ) krug p . j . , vendetti j . e . & valdés á . ( 2016 ) . molecular and morphological systematics of elysia risso , 1818 ( heterobranchia : sacoglossa ) from the caribbean region . zootaxa . 4148 ( 1 ) : 1 - 137 . , available online at urltoken [ details ]
( of tridachia deshayes , 1857 ) krug p . j . , vendetti j . e . & valdés á . ( 2016 ) . molecular and morphological systematics of elysia risso , 1818 ( heterobranchia : sacoglossa ) from the caribbean region . zootaxa . 4148 ( 1 ) : 1 - 137 . , available online at urltoken [ details ]
( of rhyzobranchus cantraine , 1835 ) krug p . j . , vendetti j . e . & valdés á . ( 2016 ) . molecular and morphological systematics of elysia risso , 1818 ( heterobranchia : sacoglossa ) from the caribbean region . zootaxa . 4148 ( 1 ) : 1 - 137 . , available online at urltoken [ details ]
( of pterogasteron pease , 1860 ) krug p . j . , vendetti j . e . & valdés á . ( 2016 ) . molecular and morphological systematics of elysia risso , 1818 ( heterobranchia : sacoglossa ) from the caribbean region . zootaxa . 4148 ( 1 ) : 1 - 137 . , available online at urltoken [ details ]
( of elysiella verrill , 1872 ) krug p . j . , vendetti j . e . & valdés á . ( 2016 ) . molecular and morphological systematics of elysia risso , 1818 ( heterobranchia : sacoglossa ) from the caribbean region . zootaxa . 4148 ( 1 ) : 1 - 137 . , available online at urltoken [ details ]
( of hydropsyche kelaart , 1858 ) krug p . j . , vendetti j . e . & valdés á . ( 2016 ) . molecular and morphological systematics of elysia risso , 1818 ( heterobranchia : sacoglossa ) from the caribbean region . zootaxa . 4148 ( 1 ) : 1 - 137 . , available online at urltoken [ details ]
( of aplysiopterus delle chiaje , 1830 ) krug p . j . , vendetti j . e . & valdés á . ( 2016 ) . molecular and morphological systematics of elysia risso , 1818 ( heterobranchia : sacoglossa ) from the caribbean region . zootaxa . 4148 ( 1 ) : 1 - 137 . , available online at urltoken [ details ]
( of elysiobranchus pruvot - fol , 1930 ) krug p . j . , vendetti j . e . & valdés á . ( 2016 ) . molecular and morphological systematics of elysia risso , 1818 ( heterobranchia : sacoglossa ) from the caribbean region . zootaxa . 4148 ( 1 ) : 1 - 137 . , available online at urltoken [ details ]
( of pattyclaya ev . marcus , 1982 ) krug p . j . , vendetti j . e . & valdés á . ( 2016 ) . molecular and morphological systematics of elysia risso , 1818 ( heterobranchia : sacoglossa ) from the caribbean region . zootaxa . 4148 ( 1 ) : 1 - 137 . , available online at urltoken [ details ]
( of pterogasteron pease , 1860 ) krug p . j . , vendetti j . e . & valdés á . ( 2016 ) . molecular and morphological systematics of elysia risso , 1818 ( heterobranchia : sacoglossa ) from the caribbean region . zootaxa . 4148 ( 1 ) : 1 - 137 . , available online at urltoken note : type species designation [ details ]
( of checholysia ortea , caballer , moro & espinosa , 2005 ) krug p . j . , vendetti j . e . & valdés á . ( 2016 ) . molecular and morphological systematics of elysia risso , 1818 ( heterobranchia : sacoglossa ) from the caribbean region . zootaxa . 4148 ( 1 ) : 1 - 137 . , available online at urltoken [ details ]
members of the elysia marginata complex and the related species e . rufescens are sources of anti - cancer compounds called kahalalides , depsipeptides derived from the algal diet of the slug ; unrecognized cryptic species in this complex introduce confusion into drug discovery work by obscuring the source of new kahalalides . clarifying taxonomic uncertainty is thus important for natural products chemistry and bioprospecting for novel chemotherapeutic agents .
elysia serca from florida have been reported feeding on several species of seagrass , including halophila engelmanni , halodule beaudettei , ( formerly halodule wrightii ) , syringodium filiforme , and thalassia testudinum ( jensen 1983b ) . young plants with fully developed blades and no epiphytes or epifauna are preferentially consumed , and animals collected from halophila engelmanni were larger than those collected from thalassia testudinum ( jensen 1983a ) .
wagele , h . , stemmer , k . , burghardt , i . , & handeler , k . ( 2010 ) .
two new sacoglossan sea slug species ( opisthobranchia , gastropoda ) : ercolania annelyleorum sp . nov . ( limapontioidea ) and elysia asbecki sp . nov . ( plakobranchoidea ) , with notes on anatomy , histology and biology .
zootaxa 2676 ( 2010 ) : 1 - 28 .
information is found in the following publications : • jensen , k . r . 1982 . occurrence of elysia serca marcus in florida , with notes on the synonymy and biology of the species . journal of conchology , 31 : 87 - 94 • jensen , k . r . 1983 . factors affecting feeding selectivity in herbivorous ascoglossa ( mollusca : opisthobranchia ) . journal of experimental and marine ecology , 66 : 135 - 148 . • jensen , k . r . 1983 . further notes on the ecology and systematics of elysia serca marcus ( opisthobranchia , ascoglossa ) . j . moll . stud . suppl . 12a : 69 - 72 . • clark , k . b . , jensen , k . r . & stirts , h . m . 1990 . survey for functional kleptoplasty among west atlantic ascoglossa ( = sacoglossa ) ( mollusca : opisthobranchia ) . the veliger , 33 : 339 - 345 .
“ elysia cf . marginata sp . 4
: parapodial edges smooth , with three successive colored bands : ( 1 ) black marginal band ; ( 2 ) orange submarginal band ; ( 3 ) very thick , white submarginal band , farthest from the edge . sides of parapodia dotted by large black spots and larger white patches . tail tapering to end of body but not pointed or elongated . proximal two - thirds of rhinophores red , distal third black ; white spot on head extending up each rhinophore . rounded pericardium tapers to a point ; white with black spots .
“ elysia cf . marginata sp . 2” : parapodia with black marginal band and red submarginal band ; edges may form one siphonal opening . body covered with tiny discrete black and white spots . pointed , elongated tail with red submarginal band running to tip . proximal half of rhinophores white , distal half red - orange , with white spot at tip . rounded pericardium , solid white , no spots . four pairs of branching vessels exit renopericardium , longest pair running posteriorly towards tail with anasthomosing side branches . egg masses contain regularly spaced blobs of bright yellow extra - capsular yolk ; planktotrophic development .
elysia chlorotica is a “solar - powered” marine sea slug that sequesters and retains photosynthetically active chloroplasts from the algae it eats and , remarkably , has incorporated algal genes into its own genetic code . it is emerald green in color often with small red or white markings , has a slender shape typical of members of its genus , and parapodia ( lateral
wings
) that fold over its body in life . this sea slug is unique among animals to possess photosynthesis - specific genes and is an extraordinary example of symbiosis between an alga and mollusc as well as a genetic chimera of these two organisms .
elysia cf . marginata sp . 1
: parapodia may be high or low ; undulating edges form 3 wide siphonal openings . siphons lined with orange edges but otherwise there no continuous marginal or submarginal band of color . body covered with regularly spaced white spots and scattered black spots , dense along parapodial margin . rhinophores with black spots on green background , white tips . no extended tail ; body squared off posteriorly . oval pericardium , posterior half white with black spots ; 3 - 4 pairs of wide , bifurcating and anasthomosing dorsal vessels . egg masses contain a continuous string of black extra - capsular yolk fading into grey - white streaks ; planktotrophic development .
“ elysia cf . marginata sp . 3
: overall darker coloration than other members of the marginata - grandifolia complex . parapodial edges ruffled , with three successive colored bands : ( 1 ) continuous , thick , black marginal band ; ( 2 ) bright white submarginal band ; ( 3 ) dull orange - red submarginal band , farthest from the edge . sides of parapodia dotted by brown - black spots of uneven size , with white patches forming zig - zags along body . squared - off tail with orange and black marginal bands running along edge . rhinophores white - tipped with distal orange band and white streaks along distal half . renopericardium longer and more elongate than in other marginata complex members ; white with black spots .
sacoglossans are simultaneous hermaphrodites that cross - fertilize by means of copulation and internal fertilization ( fox 2001 ) .
populations , individuals that settled out of the plankton as juveniles in late summer begin producing eggs the following june . mean animal length decreases throughout the egg production period , apparently due to tissue resorption to offset the energetic cost of reproduction . spiral
seagrass blade . all adults disappear in late july after the period of egg production has ended ( clark 1975 ) .
earlier references reported e . serca inhabiting and feeding on ulva , sp . ( marcus 1955 , hosoe 1956 ) , but more recent information suggests a near - exclusive association with seagrasses .
the feeding strategy is typical of sacoglossans , with plant cell walls punctured by means of the radular tooth and liquid cell contents withdrawn via suction and ingested ( clark 1975 ) . plant cells which have been pierced and sucked dry are visible as darker areas on leaf surfaces .
food preference and growth experiments conducted by jensen ( 1983b ) suggest that halophila engelmanni is a preferred food source and also the florida seagrass species that allowed maximal growth . the author postulates that the preference for and marked growth on h . engelmanni is the result of the large epidermal cells of this seagrass that allow exploitation of this food type by the size and shape of the leading radular tooth in e . serca . preference for h . engelmanni may also be due to the absence of tannins , which are present in some other seagrasses and offer a degree of chemical defense against herbivores .
detailed information is lacking , but an abundance of daytime encounters by investigators suggests much of the foraging activity of the species is carried out during the day ( rudman 2004a ) .
camp dk , lyons wg , and th perkins . 1998 . checklists of selected shallow - water marine invertebrates of florida . florida marine research institute technical report tr - 3 . 238 pp .
clark kb . 1975 nudibranch life cycles in the northwest atlantic and their relationship to the ecology of fouling communities . helgolander wiss . meeresuntersuchungen 27 : 28 - 69 .
clark kb , jensen kr , and hm stirts . 1990 . survey for functional kleptoplasty among west atlantic ascoglossa ( = sacoglossa ) ( mollusca : opisthobranchia ) . the veliger 33 : 339 - 345 .
fox rs . invertebrate zoology online . laboratory exercises to accompany fox ree and barnes rb . 2004 . invertebrate zoology , a functional evolutionary approach ( 7th edition ) . brooks cole thomson , belmont , ca . 963 p .
jensen kr 1983 . factors affecting feeding selectivity in herbivorous ascoglossa ( mollusca : opisthobranchia ) . journal of experimental marine biology and ecology 66 : 135 - 148 .
marcus er . 1955 . opisthobranchia from brazil . boletim da faculdade de filosofia , ciencias e letras . universidade de sao paulo , zoologia 20 : 89 - 261 .
report by : j . masterson , smithsonian marine station submit additional information , photos or comments to : irl _ webmaster @ urltoken page last updated : october 1 , 2008
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references : • • bleakney , j . s . , 1996 sea slugs of atlantic canada and the gulf of maine . nimbus publishing & nova scotia museum , halifax , nova scotia . • gould , a . a . ( 1870 ) . report on the invertebrata of massachesetts . wright and potter : boston . 524pp .
distribution range : 42 . 3°n to 36°n ; 76 . 5°w to 70 . 6°w ; bay of fundy ( arc ) , gom ( off mass ) , western slope of newfoundland , including . . .
distribution range : 42 . 3°n to 36°n ; 76 . 5°w to 70 . 6°w ; bay of fundy ( arc ) , gom ( off mass ) , western slope of newfoundland , including the southern part of the strait of belle isle but excluding the upper 50m in the area southwest of newfoundland , and prince edward island ( from the northern tip of miscou island , n . b . to cape breton island south of cheticamp , including the northumberland strait and georges bay to the canso strait causeway ) to new jersey . [ details ]
brunel , p . ; bosse , l . ; lamarche , g . ( 1998 ) . catalogue of the marine invertebrates of the estuary and gulf of st . lawrence . canadian special publication of fisheries and aquatic sciences , 126 . 405 p . ( look up in imis ) [ details ] available for editors [ request ]
rosenberg , g . 2004 . malacolog version 3 . 3 . 2 : western atlantic gastropod database . the academy of natural sciences , philadelphia , pa . , available online at urltoken [ details ]
to biodiversity heritage library ( 8 publications ) to encyclopedia of life to global biotic interactions ( globi ) to sea slug forum ( via archive . org ) to usnm invertebrate zoology mollusca collection to itis
the type locality is massachusetts , usa . this species is found along the western atlantic coast from northern new england to north carolina ( marcus , 1980 ) .
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the parapodia in this slug are folded dorsally over the body as parapodial
wings
. the rhinophores are rolled . the base or ground color of the body is yellow - green with small red , yellow , and blue spots .
i ' ve frequently noticed pieces of ulva covered with uniform shapes like this one here .
locality : tapper ' s cove , approx . 15 m , newfoundland , canada , atlantic ocean , torbay , 20 october 2007 , gravel bottom . length : approx . 5 mm . photographer : ryan murphy .
• gould , a . a . ( 1870 ) . report on the invertebrata of massachesetts . wright and potter : boston . 524pp . pl . 17 , fig . 249 . • marcus , ev . ( 1972 ) notes on some opisthobranch gastropods from the chesapeake bay . chesapeake science , 13 ( 4 ) : 300 - 317 .
is native to the caribbean sea and is found from florida keys to bermuda .
prefers tropical reefs and thrives in environments abundant with algae , mainly at depths from 0 . 5 to 12 m .
( pierce , et al . , 2006 ; snyderman and wiseman , 1996 )
is typically green with white spots , however , indiviuduals with other colors can be found . some have a rainbow of blues and yellows decorating their frilled bodies . the elongated visceral mass of
lies dorsally on top of the foot of the animal . the parapodia , dorsal to the visceral mass , form the distinctly ruffled , lettuce - like appearance on the dorsal surface of the body . this characteristic is responsible for the common name of the species , the lettuce sea slug . although
is a mollusk , it does not have a mantle cavity , gills , or an osphradium , but does have a foot and radula .
the hermaphroditic organ , the ovatestes , is located throughout the parapodia . the hermaphroditic duct allows eggs and sperm to leave the ovatestes . ventral to the parapodia , the hermaphroditic duct splits into tubes leading to distinct male and female reproductive parts . the oviduct is the female portion of the hermaphroditic duct , leading to the female gland and the female pore . the seminal receptacle is attached to the female gland . the male potion of the hermaphroditic duct is the sperm duct , which leads to the male atrium , which contains the penis . the seminal vesicle is located under the atrium . the atrium has a small pore called the male pore . during sexual reproduction , the penis comes through the male pore and into its mate ' s female pore . sperm are ejected from the seminal vesicle of the male organs into the seminal vesicle of the mate . the sperm then internally fertilizes the eggs in the female gland .
has an egg , larval , juvenile and adult stage . egg diameter is about 120 μm , and the eggs hatch in about 15 days . larval size is approximately 290 μm . the larvae are non - feeding veligers that metamorphosize into juvenile slugs after approximately five days . juveniles are about 530 μm long . captive juvenile lettuce sea slugs are sessile underneath a light source , not moving until they have matured . once the individuals become adults , they will acquire symbiotic plastids from aquatic algae , such as
is hermaphroditic , reproducing sexually via cross fertilization , and fertilization occurs internally . during sexual reproduction , the penis comes through the male pore and into its mate ' s female pore . sperm are ejected from the seminal vesicle of the male organs into the seminal vesicle of the mate . the sperm then internally fertilizes the eggs in the female gland .
species ; for other species clutch size ranges from 30 to 500 . specific mating behaviors for
, has a lifespan just under a year . larvae of this species arrive at the end of the summer months , grow to maturity and produce eggs in june and july , and die by late july .
is a mobile creature , only sessile as juveniles to gain energy from a light source . this species is hermaphroditic and will meet with another individual to reproduce . there is no available information as to their social behavior , territory size , and methods of communication .
use slime secretions to communicate and tentacles to receive messages . the role of rhinopores is usually for chemoreception as well , but in nudibranchs , this role may vary with genera . chemoreception is the main receptive channel for feeding , avoiding predators and toxins and to synchronize mating . visual reception in gastropods is still being investigated .
is a herbivorous suctorial feeder . this species will eat the cell sap of algae but do not digest all of it . the lettuce sea slug will use its radula to pierce algal cells and suck their contents out by using its pharynx . some of the chloroplasts that
eat are not digested . instead , they are funneled through specific passages in the digestive tract and stored in the parapodia . these chloroplasts , which can live inside the
, specimens kept in the dark for 28 days were found to have lower survival rates ( up to - 30 % ) than those kept in the light . this leads us to believe that kleptoplasts provide these mollusks with extra energy to compensate for a shortage of food .
( curtis , et al . , 2005 ; fox , 2001 ; snyderman and wiseman , 1996 )
is not of any major economic importance to humans , but it is sold in the aquarium trade .
does not have any special conservation status , but like other species of the genus , it has not been evaluated .
valentina noto ( author ) , rutgers university , kerry queenan ( author ) , rutgers university , david v . howe ( editor ) , rutgers university , renee mulcrone ( editor ) , special projects .
living in the southern part of the new world . in other words , central and south america .
having body symmetry such that the animal can be divided in one plane into two mirror - image halves . animals with bilateral symmetry have dorsal and ventral sides , as well as anterior and posterior ends . synapomorphy of the bilateria .
having a body temperature that fluctuates with that of the immediate environment ; having no mechanism or a poorly developed mechanism for regulating internal body temperature .
a large change in the shape or structure of an animal that happens as the animal grows . in insects ,
incomplete metamorphosis
is when young animals are similar to adults and change gradually into the adult form , and
complete metamorphosis
is when there is a profound change between larval and adult forms . butterflies have complete metamorphosis , grasshoppers have incomplete metamorphosis .
the area in which the animal is naturally found , the region in which it is endemic .
reproduction in which eggs are released by the female ; development of offspring occurs outside the mother ' s body .
the business of buying and selling animals for people to keep in their homes as pets .
structure produced by the calcium carbonate skeletons of coral polyps ( class anthozoa ) . coral reefs are found in warm , shallow oceans with low nutrient availability . they form the basis for rich communities of other invertebrates , plants , fish , and protists . the polyps live only on the reef surface . because they depend on symbiotic photosynthetic algae , zooxanthellae , they cannot live where light does not penetrate .
the region of the earth that surrounds the equator , from 23 . 5 degrees north to 23 . 5 degrees south .
audesirk , t . , g . audesirk . 1983 . behavior of gastropod molluscs . pp . 1 - 94 in a willows , ed .
, vol . 8 . orlando , florida : academic press , inc . .
( risso , 1818 ) : ( sacoglossa : opisthobranchia ) during periods of food shortage .
clark , k . 1975 . nudibranch life cycles in the northwest atlantic and their relationship to the ecology of fouling communities .
) come from several algal species , and are also different from those in juvenile slugs .
. usa : texas a & m university press . accessed june 06 , 2011 at
fox , r . 2001 .
tridachia crispata
( on - line ) . invertebrate anatomy online . accessed june 06 , 2011 at urltoken .
krug , p . 2009 . not my “type” : larval dispersal dimorphisms and bet - hedging in opisthobranch life histories .
and a new species of kleptoplastic sacoglossan sea slug ( gastropoda : opisthobranchia ) from the florida keys , usa .
trench , r . , r . greene , b . bystrom . 1969 . chloroplasts as functional organelles in animal tissues .
risso a . ( 1818 ) . mémoire sur quelques gastropodes nouveaux , nudibranches et tectibranches observés dans la mer de nice . journal de physique , de chimie , d ' histoire naturelle et des arts . 87 : 368 - 377 . , available online at urltoken page ( s ) : 375 [ details ]
( of elysiobranchus pruvot - fol , 1930 ) pruvot - fol a . ( 1930 ) diagnoses provisoires ( incomplètes ) des espèces nouvelles et liste provisoire des mollusques nudibranches recueillis par mme a . pruvot - fol en nouvelle cadédonie ( ile de pins ) . bulletin du muséum national d ' histoire naturelle ser . 2 , 2 : 229 - 233 . page ( s ) : 230 [ details ]
( of elysiella verrill , 1872 ) verrill , a . e . ( 1872 ) . brief contributions to zoölogy , from the museum of yale college . no . xx . recent additions to the molluscan fauna of new england and the adjacent waters , with notes on other species . american journal of science and arts . ( 3 ) 3 ( 15 ) : 281 - 290 ; pl . 6 - 8 . , available online at urltoken page ( s ) : 283 - 284 [ details ]
( of pterogasteron pease , 1860 ) pease w . h . ( 1860 ) . descriptions of new species of mollusca from the sandwich islands . proceedings of the zoological society of london . 28 : 18 - 36 , 141 - 148 . , available online at urltoken page ( s ) : 35 [ details ]
( of thallepus swainson , 1840 ) swainson w . ( 1840 ) a treatise on malacology or shells and shell - fish . london , longman . viii + 419 pp . , available online at urltoken page ( s ) : 250 , 359 [ details ]
( of aplysiopterus delle chiaje , 1830 ) delle chiaje s . ( 1823 - 1831 ) . memorie sulla storia e notomia degli animali senza vertebre del regno di napoli . napoli : fratelli fernandes ( vol . 1 ) , and società tipografica ( vol . 2 - 4 ) . vol . 1 , pp . i - xii , 1 - 84 [ 1823 ] , pp . 1 - 184 [ 1824 ] ; vol . 2 , pp . [ 1 - 4 ] + 185 - 224 [ 1825 ] , pp . 225 - 444 [ 1826 ] ; vol . 3 , pp . i - xx , pp . 1 - 232 [ 1828 ] ; vol . 4 , pp . i - vii [ 1831 ] , 1 - 116 [ 1830 ] , pp . 117 - 214 [ 1831 ] ; pl . 1 - 4 ; pl . 1 - 69 [ date ? ] , pl . 70 - 109 [ 1830 ] [ dates according to sherborn , 1922 ] . , available online at urltoken page ( s ) : vol . 4 , p . 31 [ details ]
( of hydropsyche kelaart , 1858 ) kelaart , e . f . ( 1858 ) . description of new and little known species of ceylon nudibranchiate molluscs , and zoophytes . journal of the ceylon branch of the royal asiatic society . 3 ( 1 ) : 84 - 139 . , available online at urltoken page ( s ) : 107 [ details ]
jensen , k . r . ( 2007 ) . biogeography of the sacoglossa ( mollusca , opisthobranchia ) . bonner zoologische beiträge . 55 : 255–281 . [ details ]
( of elysiella bergh , 1871 ) händeler k . & wägele h . ( 2007 ) preliminary study on molecular phylogeny of sacoglossa and a compilation of their food organisms . bonner zoologische beiträge 55 : 231 - 254 . [ details ]
( of elysiobranchus pruvot - fol , 1930 ) jensen , k . r . ( 2007 ) . biogeography of the sacoglossa ( mollusca , opisthobranchia ) . bonner zoologische beiträge . 55 : 255–281 . [ details ]
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great exuma , bahamas , western atlantic . depth : 1m . february 03 , 2004 , on sea grass halodule wrightii . upper : 5mm , lower : 4mm . photos : marina poddubetskaia
the animals look pale / starving because they cannot retain chloroplasts . i think this is because seagrass chloroplasts are not as robust as those of
siphonalean
algae . in our chloroplast symbiosis survey paper we had to measure c - 14 uptake per animal because there was so little chlorophyll in these animals that we could not measure on a chlorophyll basis . we also found high levels of
dark - fixation
, and thus no net photosynthesis .


aedes camptorhynchus , the southern saltmarsh mosquito , is responsible for transmitting the ross river virus , which causes ross river fever .

the mosquito had become established in new zealand , after it was accidentally transported from australia to hawke ’s bay , in 1998 from where it dispersed to another 10 localities mainly on the north island .

it was declared to be eradicated in 2010 .

aedes camptorhynchus

modelling the ecology of the coastal mosquitoes aedes vigilax and aedes camptorhynchus at port pirie , south australia .
modelling the ecology of the coastal mosquitoes aedes vigilax and aedes camptorhynchus at port pirie , south australia . - pubmed - ncbi
aedes camptorhynchus , or southern saltmarsh mosquito , is responsible for transmitting the ross river virus , which causes ross river fever .
map illustrating dispersal study trap sites and numbers of marked ae . camptorhynchus recaptured .
biology of the ross river virus vector mosquito ochlerotatus camptorhynchus in an urban environment . honors thesis .
total number of mosquitoes collected per trap per night by buffer distance during the course of the study and percentage of ae . camptorhynchus .
scatter plot showing the number of marked ae . camptorhynchus collected per trap night over the course of the study versus distance from the release point .
once it’s made its way to metropolitan regions , the virus can be spread from person to person by mosquitoes . common backyard mosquitoes , especially aedes notoscriptus , can transmit the virus but as these mosquitoes are not particularly abundant , don’t fly vary far and will just as likely bite animals as humans , they’re unlikely to drive major urban outbreaks of the disease . this mosquito doesn’t pack the same virus - spreading - punch as mosquitoes such as aedes aegypti that spreads dengue , chikungunya and zika viruses . aedes aegypti isn’t in victoria .
the restoration of tidal flows to hexham swamp resulted in an initial increase in the abundance of aedes vigilax . these increases resulted in substantial nuisance - biting impacts . however , in subsequent seasons , the populations of aedes vigilax levelled out to comparable levels to those of the surrounding estuarine wetlands . the net result has generally been that the long - term moderate increases in aedes vigilax populations have been balanced by reductions in culex annulirostris and coquilettidia linealis populations as the wetlands shifted from freshwater to saline . the health of the wetlands , as well as the local estuary , is improving .
two mosquito species , aedes camptorhynchus ( thomson ) and aedes vigilax ( skuse ) ( diptera : culicidae ) are responsible for significant nuisance biting and disease transmission in southern coastal australia . mosquito abundance , tide height , temperature and rainfall data were collected over three summer seasons ( 2002 , 2003 , 2004 ) at port pirie , south australia and subjected to statistical analysis to develop ecological models for predicting problem mosquito outbreaks . a logistic regression model for ae . camptorhynchus gave a predictive r ( 2 ) of 0 . 30 using mean air temperature , whereas , for ae . vigilax , tide height , mean air temperature and day length yielded a regression with an r ( 2 ) of 0 . 68 . these models identify significant environmental drivers for both species and may be useful in the prediction of future outbreaks , particularly of ae . vigilax .
saltmarshes are home to one of our most important pest and vector mosquito species . while it is important to remember that aedes vigilax is an australian native animal and just as much a part of our wetland ecosystems as fish and birds , there is little doubt that it can have substantial impacts with regard to nuisance - biting and the transmission of ross river virus .
one of the important considerations when assessing mosquito risk was that there had been a dramatic transformation of the areas surrounding the wetlands in the last 20 years . what was once agricultural land was now residential . this is the same situation right along the east coast of australia , the rapid urbanisation and swelling residential populations along the coast have put people in the firing line of aedes vigilax .
muddy lakes are the remnants of minninup lakes after large drains were cut through the area to remove water that is now diverted out to sea , allowing more access to land for farming purposes . these drains are still present today , although they are not maintained . mosquito activity in the area is relatively high and usually rainfall - driven , with large numbers of adults collected previously in the vicinity , the majority being ae . camptorhynchus , and a high level of public complaints coming from surrounding areas ( shire of capel , unpublished data ) . acid sulphate soils occur naturally around muddy lakes 25 , 26 and are an issue for mosquito management , because they reduce the efficacy of chemical larvicides .
health authorities in victoria have been warning of mosquito - borne ross river virus for much of the summer . the state is experiencing one of its worst outbreaks of the disease but cases have mostly been across inland regions . now it’s hit melbourne . how has this happened ?
ross river virus is the most commonly reported mosquito - borne disease in australia . there are usually about 5 , 000 cases across australia . however , in 2015 there was a major spike in activity with around 9 , 000 cases reported . it is a common misconception that the disease is only found in northern regions of australia . i’m often told “i heard the disease is moving south from qld ? ” that’s not the case .
the virus is just as much a natural part of the australian environment as the mosquitoes and the wildlife that maintain transmission cycles .
while there are generally more cases in northern australia , nowhere is safe . some of the largest outbreaks have occurred in southern regions of western australia , south australia , victoria and even tasmania .
the virus is widespread but is generally associated with rural regions . a driving factor in determining the activity of ross river virus is that more than just mosquitoes are involved in outbreaks . the virus is maintained in the environment in native wildlife , especially kangaroos and wallabies . even when and where there are high numbers of mosquitoes , without wildlife , outbreak risk is low . this is the reason why any clusters of locally infected cases in metropolitan regions are typical in areas where there are wetlands , wildlife and mosquitoes occurring together . we’ve seen this on the urban fringe of sydney and perth in recent years .
the announcement of locally acquired cases in the suburbs of frankston and casey , in melbourne’s south - east , has taken many by surprise . should it have ?
victoria is no stranger to mosquitoes and outbreaks of mosquito - borne disease . there are mosquito surveillance and mosquito control programs in place in many regions and historically there have been major outbreaks of mosquito - borne disease . from freshwater flood plains of the inland to the tidally flooded estuarine wetlands of the coast , victoria has diverse and often abundant mosquitoes . but cases in the metropolitan region are rare .
victorian mosquitoes are not all bad but over a dozen different mosquito species can spread ross river virus .
the region where these cases have been identified are in proximity to bushland and wetland areas . there is no doubt plenty of mosquitoes and suitable wildlife too . while this is the first time local transmission has been documented , that doesn’t mean the virus hasn’t circulated in the past , or even that cases may have occurred .
for individuals infected but only suffering mild symptoms , the illness can be easily discounted as nothing more than a mild case of the flu . without appropriate blood tests , these cases never appear in official statistics . for this reason , many mosquito researchers believe that the number of notified cases across the country is just the tip of the iceberg with many milder infections going diagnosed .
it is difficult to know for sure . the two most likely explanations are that either environmental conditions were ideal for mosquitoes and suitable populations of wildlife were present so that the virus was much more active in the local environment than previously . the second explanation is that the virus may have been introduced to the region by a traveller or movement of wildlife . in much the same way zika virus made its way from se asia to south america in the last few years , mosquito - borne viruses move about in people and animals , much less so than mosquitoes themselves ( but that isn’t impossible either ) .
victoria ( as well as inland nsw ) is experiencing one of its largest outbreaks of ross river virus on record following significant flooding of inland regions . with so much activity of the virus in the region , perhaps an infected bird or person travelling to the metropolitan region brought the virus with them . when bitten by local mosquitoes , the virus started circulated among local mosquitoes and wildlife .
most people infected by ross river virus are bitten by a mosquito that has previously fed on a kangaroo or wallaby .
we’re unlikely to see significant spread of ross river virus across melbourne but that doesn’t mean victorians should be complacent . as there is no cure for ross river virus disease , the best approach is to avoid being infected in the first place . preventing mosquito bites is the best approach . for my tips and tricks on avoiding mosquito bites see this recent paper in public health research and practice as well as my article for the conversation .
this is a special guest post from dr abbey potter , senior scientific officer , environmental health hazards , wa health . i’m currently mentoring abbey as part of the public health advocacy institute of wa ( phaiwa ) mentoring program . its been a great experience as we navigate through some of the strategies to raise awareness of mosquito - borne disease and advocate for better approaches to addressing the public health risks associated with mosquitoes .
living in wa , we’re all too familiar with the pesky mosquito . we know they bite but what we often don’t consider is that they can transmit serious and sometimes deadly diseases . in fact , a recent survey of locals indicated that knowledge of mosquito - borne disease is pretty limited , particularly among younger adults aged 18 - 34 years and those living in the perth metro . it’s pretty important we’re aware of the risks posed by these pint - sized blood suckers and how you can avoid them… and here’s why !
on average , more than 1 , 000 people will be infected with a mosquito - borne disease in wa every year . our mossies can transmit ross river virus , barmah forest virus , west nile virus ( kunjin substrain ) and murray valley encephalitis viru s . all four cause diseases that are debilitating at best , causing weeks to months of symptoms . murray valley encephalitis is limited to the north of the state but is so serious it can result in seizures , coma , brain damage and even death .
forget the bush , most people bitten in their own backyard . west aussies are all very prone to getting eaten alive while socialising outdoors but if you’re up in the north of the state , you’ve also got a much higher likelihood of being bitten while boating , camping or fishing or working outside , compared to the rest of the state .
and don’t think you’re off the hook when you head off on holidays . a further 500 wa residents return from overseas travel with an exotic mosquito - borne disease every year . heading to bali ? beware of dengue , especially young adult males who return home with the illness more than others . there is limited mosquito management in many overseas countries where disease - transmitting mozzies can bite aggressively both indoors and throughout the day . this catches west aussies off guard , as we are accustomed to mozzies biting outdoors , around dusk and dawn . when you’re in holiday mode it’s likely that you’ll be relaxing , having a couple of drinks and not thinking about applying repellent . oddly enough , mosquitoes may actually be more attracted to people whose body temperature is higher . this happens naturally when you consume alcohol , so best pull out the repellent before you crack your first beer .
despite our attractiveness to mosquitoes , we aren’t really aware of the most effective ways to avoid bites or how we can do our bit to reduce breeding in our own backyards . if you live by the mantra cover up . repel . clean up you’ll have no problems !
if you know you are going to be outdoors when mosquitoes are active , wear loose , long - fitting clothing that is light in colour . believe it or not , mosquitoes can bite through tight pants as tough as jeans – i’ve witnessed it !
if you’re staying in accommodation that isn’t mosquito - proof , consider bed netting .
try to keep children indoors when mosquitoes are most active . if exposure can’t be avoided , dress them appropriately and cover their feet with socks and shoes . pram netting can also be really useful .
admittedly , it’s not always practical to wear long sleeves during our warm summer nights , so there are going to be times when you need to use repellent . choose a product that actually works and apply it appropriately so it does the job . despite our best intentions , this is where we often go wrong . there are a few basic things to cover here , so stick with it !
science tells us that the best active ingredient for repelling mosquitoes is diethyltoluamide ( deet for short ) or picaridin . you need to look for either one of these names on the repellent label under the ‘active constituents’ section .
unfortunately , natural repellents and anything wearable ( e . g . bands , bracelets or patches ) have very limited efficacy . experts don’t recommend you use them and i consider this very wise advice . it only takes a single mosquito bite to become infected and chances are you will receive at least one if you rely solely on a product of this nature . it just isn’t worth the risk .
the next thing to consider is the percentage of the active ingredient . this can range anywhere from 7 % to 80 % which can make choosing a repellent confusing . just remember , the higher the percentage , the longer the product will remain active for . it doesn’t mean it will repel mosquitoes better .
a repellent containing 16 - 20 % deet will provide around 4 - 6 hours of protection , and is a good place to start . repellents labelled ‘tropical strength’ usually contain greater than 20 % deet – they are useful when you spend longer periods exposed to mosquitoes or if you are heading to a region where dengue , malaria or zika is problematic . kids repellents usually contain picaridin or < 10 % deet .
sometimes it can be tricky to work out the percentage of the active ingredient . you can see the bushmans example below states this clearly , but the other bottles list the ingredient in grams per litre ( g / l ) . no need for complex maths – just divide by 10 and you have the magic number ! for example , the rid label below reports the product contains 160g / l of deet . this would convert to 16 % deet – easy !
no doubt we would all prefer if repellents didn’t feel quite so gross on our skin or didn’t smell so bad . even i have to admit that before i moved into this field , i was guilty of putting just a dab here and a dab there . unfortunately , this is flawed logic that will only result in you being bitten !
repellents must be applied correctly to be effective . that means reading the label and applying it evenly to all areas of exposed skin . remember to reapply the product if you are exposed to mosquitoes for longer than the repellent protects you for . you’ll also have to reapply the repellent after sweaty activity or swimming .
mosquitoes need water to breed , but only a very small amount . water commonly collects in a range of things you may find in your backyard including pot plant drip trays , toys , old tyres , trailers and clogged up gutters . mosquitoes also love breeding in pet water bowls , bird baths and pools if the water is not changed weekly or they are not well maintained . rain water tanks can also be problematic so place some insect proof meshing over any outlets . when you’re holidaying , cover up or remove anything that may collect water .
if you need more official info from wa health about mosquito - borne disease or simple ways to prevent being bitten click here . and if you want to read more about how much west aussies know ( or don’t know ) about mossies , check out abbey’s excellent paper here ! joint the conversation too on twitter by following abbey and cameron .
mosquitoes can be more than a nuisance . they pose health risks but could also erode the good will of the community for wetland rehabilitation projects . wetland rehabilitation needs mosquito control .
it’s a warm february evening . a small and anxious group of residents have gathered in a local community hall to discuss the implications of a local wetland rehabilitation project . some are angry . one of the first questions comes from an elderly gentleman . close to tears , he explains how his grandchildren no longer visit due to the plagues of mosquitoes that engulf his property day and night . “what are you guys going to do about it ? ” he pleads .
i learnt a valuable lesson that night . trying to explain the best mosquito repellent to use doesn’t go down too well when an audience is facing some significant nuisance - biting impacts around their homes . it doesn’t matter how much deet is in the repellent , it may well work but is it something you need to wear all day just to get the day to day jobs done around the house ? something more substantial is required and , with hindsight , should have been in place before the first waves of mosquitoes left the local wetlands .
sea level rise and climate change is putting pressure on saltmarshes and urbanisation is eating away land that would otherwise accommodate a landward shift in estuarine habitats . there is nowhere for saltmarshes to spread to so they’re destined to be swallowed up by mangroves . while the mangroves are valuable themselves , they don’t provide the same critical habitats required by many of the internationally protected migratory shorebirds that rely on saltmarshes . saltmarsh habitats could well disappear from much of the east coast in coming decades if sea levels rise as expected and mangroves continue their march landward .
historically , many of the saltmarshes along the east coast were drained or filled to enable increased cattle grazing ( although much of it was under the guise of protection from flooding ) . tidal flows were cut off with the construction of levee banks and installation of flood gates . notwithstanding the impacts of grazing , without tidal exchange , the habitats became brackish water to freshwater dominated systems with a dramatic change in vegetation . saltmarsh and sedgeland vegetation was steadily replaced by reeds and rushes . invasive plants such as phragmites quickly took over many of these wetlands .
to combat the degradation of wetlands and impending loss due to climate change , there has been some ambitious wetland rehabilitation projects planned . one of the largest in the southern hemisphere is the hexham swamp rehabilitation project . much can be learned from the experience in this wetland just west of newcastle , nsw , and applied to rehabilitation projects , not only in australia but overseas as well .
rehabilitation of hexham swamp involved the staged opening of existing floodgates to reinstall tidal flows to an otherwise freshwater system . many aspects of this project were considered and it is unsurprising that one major issue was the possible impact of mosquitoes . mosquito populations were something of legend in this area , enough so that there is a “big mosquito” outside the local bowling club affectionately known as “ ossie the mossie ” ( coincidently , “ossie” celebrated her 20 th birthday in march 2014 ) .
the prospect of mosquito control was raised in the early stages of the rehabilitation planning but there was great reluctance from the local authorities to head down that path . the problem is that broad scale mosquito control and ecological rehabilitation are often seen at opposite ends of the wetland management spectrum . i’ve experienced this many times first hand , from scepticism regarding the non - target impacts of biological larvicides to “apocalypse now” jokes as helicopters go about routine spraying of local wetlands .
the hangover from the actual and perceived impacts of pesticide use more than 50 years ago is still present in the minds of many responsible for managing local wetlands . i say perceived as the development of environmentally sustainable mosquito control programs over the past two decades may not be appreciated amongst those charged with managing wetlands and wildlife .
i feel we need to continue building the case for the range of mosquito control strategies available for our coastal wetlands . not only do we need to convince local authorities that mosquito populations can be minimised without adversely impacting the local environment but that mosquito control should be a critical consideration in wetland rehabilitation projects . it also has the potential to reduce mosquito - borne disease .
we know that the direct non - target impacts of bacillus thuringiensis israelensis and s - methoprene are minimal and there is growing evidence that the indirect impacts on local wildlife due to reduced mosquito populations isn’t a major concern . well - designed projects can also minimise the frequency of treatments while reducing peaks in mosquito activity .
it seems our coastal bats populations are mostly eating moths , not mosquitoes so there is unlikely to be any significant impact on these bats resulting from reduced food . there is no reason why the judicious use of larvicides can’t knock the top off abundant mosquito populations , reduce the pest impacts on local community and not pose a risk to local wildlife . perhaps it should be considered a critical component of wetland rehabilitation ?
in speaking with wetland managers , i try to instil with them the importance of mosquito control . there is a risk that swarms of nuisance biting mosquitoes may erode the good will in the community for wetland rehabilitation . these systems , particularly in the early phases of rehabilitation don’t represent pristine environments and while there may not be a desire to establish ongoing mosquito control programs , some control may prove useful while the wetland comes back into balance with the changed environmental conditions .
rehabilitation takes time and while there is substantial breakdown of freshwater vegetation it is not going to be ideal for fish and other mosquito predators . it is likely to provide ideal conditions for mosquitoes . over time , however , fish are likely to increase in both their abundance and penetration into the wetlands and greater tidal flushing will make many of the wetland habitats generally unsuitable for mosquitoes .
perhaps there is benefit in undertaking control as a show of good will to the local community ? after all , engagement with the local community will be critical in the success of wetland rehabilitation projects .
mosquito control is only a short - term fix and if the rehabilitation of estuarine wetlands is not carefully planned , there may well be ongoing mosquito impacts . however , reducing any initial impacts will go a long way to ensuring continued engagement of the community with the local wetlands . cost and the operational considerations may be a barrier for organisations unfamiliar with broadscale mosquito control but these issues can be overcome with the expertise that exists in many parts of the country .
in summary , it is important that mosquito management be considered in the planning process of major wetland rehabilitation projects . there is little doubt that such projects will be required into the future as saltmarsh habitats and other estuarine wetlands are threatened but protection wetlands shouldn’t mean increasing mosquito populations . a balance is required between conservation of environmental health and protection of human health .
a longer version of this article originally appeared in “mosquito bites” ( the bulletin of the mosquito control association of australia ) .
beer , high tides , public holidays and blood thirsty mozzies . the perfect mix to set the media into a spin . how can you get the best public health messages out about mosquito bite protection ?
it was almost as tricky managing the media this summer as it was the mozzies . since late october , i’ve been interviewed on almost 50 occasions . a mix of pre - dawn calls from radio stations to live crossed to nationally broadcast breakfast televsion to taking talkback and dealing with mobile phone dropouts . it was a sweaty and stressful couple of months… . and ‘mozzie season’ still isn’t over just yet .
the last few years have followed a pretty similar pattern . i get my first few calls around august / september . this is usually when we get our first blast of unseasonal heat and there are typically a few s tories about people noticing bugs about their home and are worried about an early start to the mozzie season .
this year we genuinely did have an early start to the mozzie season . the warmest spring on record kicked off the mozzie season early and one of the first big stories i did for channel 9 news was almost derailed by swarms of mozzies ! a few of the crew needed to retreat to the safety of their car . you can listen to me speaking with abc new radio here .
following plenty of rain in early december , mosquito populations starting jumping up along the coast . just in time for the christmas holidays . during this period it is pretty common to respond to requests from media to talk about mozzies , particularly if there have been some public health alters from local health authorities .
a few things helped keep mozzies in the news . there were health warnings from local authorities after the detection of ross river virus in southern sydney . there were warnings about a new outbreak of dengue in far north qld . flooding in central australia also prompted warnings of outbreaks of mosquito - borne disease .
then there was this piece i wrote on why mosquitoes bite some people more than others that attracted plenty of attention too… . over 1 . 2 million readers in fact ( thanks to republication by ifls , sbs and mamamia ) !
as we headed towards our national holiday weekend and australia day celebrations , there were warnings that a big boost in mosquito populations were on their way . yes , “mozziegeddon” was coming and the pesky little biters were set to turn our long weekend into a “ moztralia day bloodbath “ . worse still , those taking part in the traditional australia day past time of beer drinking were being scared off the booze by fears of becoming “ mozzie magnets “ .
there is little surprise that stories about beer drinking and mozzies attract plenty of attention . it does almost every year . however , this year was a little different because health authorities were concerned about potential increases in mosquito populations and given recent detections of mosquito - borne pathogens such as ross river virus , there was concern about public health risks . those risks range from both the north coast of nsw to north - west of wa !
there was plenty of mosquito media coverage from se qld too . local authorities were battling big mosquito populations and trying to control “3000 known mosquito breeding sites” the next generation of mosquitoes hatching following heavy rain and tidal flooding of local wetlands .
local insect repellent manufacturers were also taking advantage of the boost in mosquito numbers . i’ve noticed an increase in tv and radio ads spruiking mosquito repellents and aerogard also sent out “ swat ” teams to local parklands around sydney on australia day promoting their “ mozzie index “ * website !
in the lead up to the long weekend i spoke with the breakfast show on 2ue ( you can listen to the interview via link ) , angela catterns on 2ue , chris smith on 2gb as well as robbie buck and linda mottram on 702 sydney . i provided a couple of brief grabs for news bulletins and even did my first live cross for the sunrise breakfast program on channel 7 . you can also listen to interviews with 2ser , abc perth and abc south east sa . [ update 26 february 2015 . there were a few more interviews , one fun one was with richard stubbs for 774 abc melbourne and you can listen in below , another was with dom knight on 702 abc sydney and you can read about that here . and i also chatted with patricia karvelas on radio national drive and you can listen here . ]
it can be tricky getting good public health messages out during these very brief interviews , particularly for television . radio can be pretty good as there is often plenty of time to get the message out ( sometimes even time for talk back callers and questions ) but for some of the commercial stations , time can be brief . television is particularly challenging , i usually spend more time in the make up chair than being interviewed !
this summer i’ve been determined to ensure some key messages get out , particularly about choosing and using insect repellents most effectively . this is an issue i feel strongly about and i have an article coming out shortly in the medical journal of australia on how local health authorities can do this a little better .
the two key messages were “if you’re using botanical based topical repellents , they need to be reapplied more frequently than the recommended deet and picaridin based repellents” and “when using repellents , they must be applied as a thin coat over all exposed skin to get the best protection , not a dab here and there” .
overall , i think i managed to get these two points into most radio and television interviews and i was happy to see that the general message got through in a lot of the print / online media too .
below are some of my tips on getting a specific message out while dealing with the media .
1 . prepare . you would practice giving a conference presentation ahead of time so why not prepare for media ? think about the messages and how you can deliver them . what questions might you get asked ? what will be the style of the presenter ? are there any questions you may be asked that you may want to avoid answering ( e . g . questions of a political nature or something that could embarrass your employer ) ? how can you do that ?
2 . learn from the professionals . if know you’re going to do some media in the coming weeks or months . spend some time listening to talk back radio and reading newspapers . take note of the number and length of quotes journalists use in articles . make their job a little easier by providing concise quotes where possible . how do radio broadcasters conduct interviews ? listen to politicians and journalists being interviewed . how do they get their message across ( or don’t in some circumstances ) . what makes you “switch off” from an interview – is it the topic or interviewee ?
3 . create bridges between questions and your message . this is the thing i’ve found quick tricky but once you’ve got the hang of it , you can more effectively get the message out . there may not be a question asked that specifically relates to the message you need to get out . learn how to transition from a brief response to the question asked onto the key messages you want to get out there . don’t just launch off into your spiel at first chance , it is important to engage with presenter too , its a subtle art but like all things , it is only hard before it becomes easy .
4 . post - interview review . i’ll often take notes after an interview that help prepare for the next one . things like the type of questions asked or how i answered questions , particularly if i feel my responses were clunky or i rambled a little ! i’ve always found it interesting that slight differences in the way that questions are asked can often throw you off balance in an interview . if there are talkback callers , what questions were asked , especially if there was something out of left field ! making a note of these can help when preparing for the next batch of media .
5 . keep track of media activity . you never know when it may come in handy when applying for a promotion , grant or new job . i try to keep track of all media activities by recording the date , journalist , media outlet and brief description of topic . you can also speak to your local media and communications unit to see if they gather statistics on these things too . the team at the university of sydney are great and it is fascinating to compare the analysis of different media activities , their reach and estimated value .
perhaps the trickiest thing in all this is assessing whether this media activity actually helped the community prevent mosquito bites . it will be almost impossible to tell from human notification data on mosquito - borne disease given the numbers jump around so much from year to year anyway . what really need is some more attitudinal studies to see how people seek out and follow advice provided by local health authorities on mosquito - bone disease prevention strategies . another thing for the “to do” list
[ update 21 march 2015 ] following the detection of ross river virus amongst mosquitoes collected in nsw combined with a dramatic increase in human notifications of ross river virus disease , there was another wave of interest by local media . you read a piece at the sydney morning herald and watch a segment with me from nine news .
* a disclaimer : i provided some assistance to a local pr company back in 2012 that developed the “mozzie index” for aerogard , particularly some info on the associations between mosquitoes and local environmental conditions .
the protection and rehabilitation of urban wetlands is critical . they are under threat from urbanisation and a changing climate climate but perhaps the greatest risk is disengagement from the community with many not really know the true value of our wetlands .
i have had a long and productive working relationship with the sydney olympic park authority ( sopa ) . one of the most enjoyable activities has been serving as a member of the wetlands education and training ( wet ) program advisory panel . a small group of wetland scientists assist sopa develop and coordinate workshops for scientists , managers , policy makers and teachers . the program has been in place since 2002 and over 30 workshops have been held since then . there have two very successful “managing mosquitoes” workshops in recent years with the next scheduled for 2015 ( keep your eyes out for that one )
after ten years of working with a diverse range of professionals , it was decided that the collected wisdom of those groups and individuals should be brought together in the form of a resource for those managing urban wetlands . in particular , it would draw on many of the experiences within the wetland of sydney olympic park .
the “ wet ebook : workbook for managing urban wetlands in australia ” was launched on thursday 28 november 2013 in conjunction with a two - day workshop on constructed wetlands management . the ebook was officially launched by michael knight , chair of the sydney olympic park authority . michael is well connected to the sydney olympics , serving as minister for the olympics between 1995 and 2001 in nsw , and it could be argued that , without the hosting of the 200 olympics , many of the current wetlands around the area may not exist today .
i’ve contributed three chapters to the ebook . they can be downloaded individually but don’t just stick to the mozzies , there is lots more valuable information contained within the 400 or so pages . a wide range of topics , across broad topic areas of estuarine wetlands , freshwater wetlands , monitoring , developing a plan of management , are covered and a concluding section brings everything together . in fact , i was given the opportunity to be lead author on the final chapter , identifying and bringing together many of the challenges faced by urban wetlands and mapping out a way forward for wetland conservation .
webb c . e . ( 2013 ) managing mosquitoes in constructed freshwater wetlands . ‘workbook for managing urban wetlands in australia’ ( ed . s . paul ) 1st edn . ( sydney olympic park authority ) isbn 978 - 0 - 9874020 - 0 - 4
webb c . e . ( 2013 ) managing mosquitoes in coastal wetlands . ‘workbook for managing urban wetlands in australia’ ( ed . s . paul ) 1st edn . ( sydney olympic park authority ) isbn 978 - 0 - 9874020 - 0 - 4
webb c . e . et al . ( 2013 ) facing the challenges of managing urban wetlands in australia : the way forward . ‘workbook for managing urban wetlands in australia’ ( ed . s . paul ) 1st edn . ( sydney olympic park authority ) isbn 978 - 0 - 9874020 - 0 - 4
unless otherwise acknowledged , all photos used on this website have been taken by me ( cameron webb ) . feel free to use them for non - commercial purposes but please acknowledge their source .
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andrew jardine , * peter j . neville , colin dent , carla webster , and michael d . a . lindsay
* address correspondence to andrew jardine , mosquito - borne disease control , department of health western australia , po box 8172 , perth business centre , perth , western australia 6849 , australia . e - mail : ua . vog . aw . htlaeh @ enidraj . werdna
this is an open - access article distributed under the terms of the creative commons attribution license , which permits unrestricted use , distribution , and reproduction in any medium , provided the original author and source are credited .
rapid population growth in western australia has resulted in increased development of land for residential housing , and new developments are often proposed close to water because of intrinsic aesthetic values . however , this placement may place future residents at risk of mosquito - borne disease , of which ross river virus ( rrv ) disease is the most common in australia . mosquito dispersal data were combined with a spatial analysis of human rrv cases to show that mosquitoes dispersed readily from larval habitat into surrounding low - and high - density residential areas and that residents living within 2 km of mosquito breeding habitat had a significantly higher rate of rrv disease . this finding highlights the importance of planning authorities in state and local governments to consider the implications of mosquito - borne disease risks when assessing residential development applications .
many residential areas in southwestern western australia ( wa ) are located in close proximity to major natural mosquito breeding habitat , and many more are being developed because of aesthetic values of living near water . however , residents in such areas may be exposed to greater risk of contracting mosquito - borne diseases , such as ross river virus ( rrv ) ( togaviridae : alphavirus ) , and intense nuisance problems at certain times of year when mosquitoes disperse from breeding habitat into surrounding suburbs . rapid population growth and subsequent pressure to develop new areas for residential housing are further exacerbating the problem .
it is , therefore , intuitive that those people living in closer proximity to potential breeding habitat are at greater risk of mosquito - borne disease , and this relationship has been shown for malaria in africa 18 , 19 and asia . 20 geographical information system ( gis ) studies in southeast queensland have shown that rrv rates are higher in areas with a greater proportion of native vegetation and wetlands 21 and adult mosquito abundance . 22 , 23 a recent study in the southwest of wa found that rrv incidence decreased with distance from a large tidal estuary with extensive mosquito breeding habitat in rural and semirural areas but found no relationship in urban areas with higher population density . 24
the present study is the first to combine mosquito mark–release–recapture data with a gis analysis of long - term disease data to determine the risk associated with proximity to mosquito larval habitat . it is important to quantify this risk to inform planning decisions for proposed new developments and mosquito control activities to protect existing communities near mosquito breeding habitat . the aim of this work is to investigate the mosquito - borne disease risk associated with dispersal of mosquitoes from a highly productive mosquito breeding site , known as muddy lakes , in the shire of capel , wa .
to 2 ha , and dayellup , a high - density urban development to the north . all three localities are known to experience high mosquito activity at varying times throughout the year . the only recreational facilities within the area are a golf club about 2 km southeast of muddy lakes and a small playground 150 m behind the golf club . substantial areas of native bushland remain in both stratham and gelorup , which support populations of western grey kangaroo (
census data show that the region of interest in this study ( gelorup–dalyellup–stratham statistical area 2 ) grew by 242 % between 2001 and 2011 , 27 and the wa department of planning has forecast an annual average population growth rate of 4 . 5 % in the shire of capel until 2026 , 28 applying additional pressure to develop land in what is one of the highest risk areas for rrv disease in wa .
ethics approval was not required , because our study evaluated data collected during the routine public health response to rrv as a notifiable disease .
many techniques have been used to study insect dispersal , 29 and those techniques specifically relating to mosquitoes have been reviewed previously . 9 the mark–release–recapture method was selected using a powdered pigment that fluoresced pink under ultraviolet light as the marking agent . this type of marking agent has been used successfully in many previous mosquito dispersal studies . 30 – 33 it provides a durable , easily recognizable mark when applied in appropriate quantities and does not impact mosquito survival or behavior . 34 , 35
five recapture transect lines were identified going in north , northeast , east , southeast , and south directions from the release site , and trap sites were selected along each at distances between 300 and 6 , 500 m from the release point . distances varied along each transect because of the limited availability of accessible locations to set the traps .
for the first night ( october 5 ) , recapture traps were placed at 300 and 600 m along transect a , 1 , 000 m along transect b , 700 m along transect c , 1 , 200 m along transect d , and 500 m along transect e . another 17 traps were placed out along five transects until the study concluded on october 19 . if a marked mosquito was found at the 3 , 500 - m trapping point , another trap was placed at the 6 , 500 - m mark . each morning , collections were scanned using an ultraviolet ( uv ) light to detect any marked mosquitoes and weighed to estimate the total quantity collected . marked mosquitoes were placed in separate specimen containers , dated , identified , and recorded . species identification and enumeration were also carried out for all mosquitoes collected every second day .
rrv is a notifiable disease under the health act ( 1911 ) , requiring all cases diagnosed by a doctor or in laboratory tests to be notified to the department of health . where possible , cases were followed up with a questionnaire to determine the most likely location of exposure and date of onset . if the case could not be contacted , residential address was assumed to be the location of exposure . two time periods of rrv notification data were included in the study based on a date of onset : the most recent outbreak year from july 1 , 2011 to june 30 , 2012 and the 10 years from july 1 , 2002 to june 30 , 2012 .
the dataset created for spatial analyses consisted of all cases for which data relating to place of exposure or residential address could be precisely geocoded to a specific cadastral lot ( a legally defined property boundary ) . in addition , if place of exposure data or residential data was not given as an exact location but could be pinpointed with reasonable confidence ( e . g . , a street corner within 250 m ) , then these cases were also geocoded . all other cases were excluded from the dataset for spatial analyses .
the border of muddy lakes was extracted from the hydrography linear spatial data layer maintained by the department of water , 38 and six 1 - km buffers were created around this lake using quantum gis 1 . 7 . 4 ( open source geospatial foundation , beaverton , or ) . 39 the intersection of the buffers with the rrv case data was used to determine the number of cases within each buffer .
property street address ( psa ) cadastral data maintained by landgate were overlaid by the bunbury regional planning scheme maintained by the western australian planning commission . addresses in areas zoned as urban or rural were retained , and all others were excluded . any other addresses not defined as a house were also excluded . the remaining dwellings were then used to calculate the background rate of rrv across the shire of capel . finally , the psa data were intersected with the buffers to determine the number of dwellings within each 1 - km buffer .
the case and cadastral data were then summed for each buffer , the rate of rrv notifications per 1 , 000 dwellings was determined , and mid - p exact 95 % confidence intervals were calculated . poisson regression was then undertaken to determine if a statistically significant trend in the rrv rate with buffer distance was present . the number of rrv cases was assigned as the dependent variable , the buffer distance was the independent variable , and the number of dwellings was the exposure variable .
finally , to determine the expected background rate , the number of rrv cases and dwellings for the whole of the shire of capel was calculated using the same methods described above . the rate for each buffer was determined to be significantly elevated if the 95 % confidence interval did not span the background rate .