bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimates of grain passage time in captive mallards
Authors: Clark Robert G. , Gentle Garry C.
Published: August 2008

Passage of six-row barley and durum wheat through the digestive tract of captive female mallards (Anas platyrhynchos) was assessed in two experiments. First, we measured esophagus-emptying time to see how quickly grain clears the esophagus. Emptying time increased with increasing meal size, and barley (sigmoid relationship) cleared the esophagus slower than durum wheat (inverse cube root relationship). Second, we weighed the cumulative mass of excreta voided by mallards to see how quickly grain was digested. Cumulative mass of excreta increased with increasing meal size and was dependent on grain type and the time elapsed after feeding. When adjusted for meal size, more excreta were voided by mallards fed barley. Excretion was rapid until about 8 h postfeeding. Durum wheat was digested at the same rate as barley. We estimated that a 60-g meal would pass from a mallard's esophagus within 3 and 7 h for durum and barley, respectively; for both grains, about 50% of the meal would be digested within 7 h. Results suggest that, in most situations, field-feeding frequency of mallards is not limited by passage time of grain through the esophagus and digestive tract, but passage time might influence diet choice during periods of foraging constraint.
A review of species of Myxobolus (Myxosporea) parasitizing catostomid fishes, with a redescription of Myxobolus bibullatus (Kudo, 1934) n.comb. and description of Myxobolus lamellus n.sp. from Catostomus commersoni in Nova Scotia
Authors: Grinham T. , Cone D. K.
Published: August 2008

Known species of Myxobolus from catostomid fishes are reviewed and Myxobolus bibullatus (Kudo, 1934) n.comb. and Myxobolus lamellus n.sp. (Myxosporea) are described from common sucker (Catostomus commersoni) in Sawler Lake, Lunenburg County, Nova Scotia. Trophozoites of M. bibullatus form saclike interlamellar cysts at the base of gill filaments. Myxobolus lamellus n.sp. forms interstitial trophozoites in secondary lamellae that envelop the capillary bed. Spores form through the cyst's vacuolated matrix, and are round with large polar capsules relative to spore length. Ten species of Myxosoma from catostomids are transferred to Myxobolus and the following revisions made: Myxobolus bibullatus (Kudo, 1934) n.comb. (syn. Myxosoma bibullatum Kudo, 1934); Myxobolus commersonii (Fantham, Porter, and Richardson, 1939) n.comb. (syn. Myxosoma commersonii Fantham, Porter, and Richardson 1939); Myxobolus ellipticoides (Fantham, Porter and Richardson, 1939) n.comb. (syn. Myxosoma ellipticoides Fantham, Porter, and Richardson 1939); Myxobolus endovasus (Davis, 1947) n.comb. (syn. Myxosoma endovasa Davis, 1947); Myxobolus microthecus (Meglitsch, 1942) n.comb. (syn. Myxosoma microthecum Meglitsch, 1942); Myxobolus multiplicatus (Reuss, 1906) n.comb. (syn. Myxosoma multiplicatum (Reuss, 1906); and Myxobolus ovalis (Davis, 1923) n.comb. (syn. Myxosoma ovalis Davis, 1923). Myxobolus meglitschi (Meglitsch, 1937) nom.nov (syn. Myxosoma rotundum Meglitsch, 1937), Myxobolus musculosus (Kudo, 1923) nom.nov. (syn. Myxosoma catostomi Kudo, 1923), and Myxobolus filamentus (Rice and Jahn, 1943) nom.nov. (syn. Myxosoma okobojiensis Rice and Jahn, 1943) are established because of specific preoccupations. Known information on myxobolids from catostomid fishes is summarized.
Lomanotus barlettai, a new species of nudibranch mollusk from the Iberian littoral, with remarks on world species of the genus
Authors: García-Gomez J. C. , Lopez-Gonzalez P. J. , García F. J.
Published: August 2008

A new, extremely cryptic dendronotoid nudibranch from southern Spain is described. Lomanotus barlettai sp.nov. is intertidal and has been found under stones together with the thecate hydroids Kirchenpaueria pinnata and Ventromma halecioides. The body is elongate with a maximum of 36 cerata on each side. These are located on three pairs of notal ridges. Each ceras shows one or two characteristic constrictions. The veil bears two pointed processes on either side and there is a cephalic ridge. The body is brown with dense gold–brown pigmented superficial dots. The radular formula is 23 × 17.0.17 (7.5-mm specimen) and the innermost tooth of each half-row is denticulate. The other teeth exhibit more marked denticulation. Extensions of the digestive gland penetrate the cerata. The ampulla is surrounded by the hermaphroditic gland and there is only a curved seminal receptacle and a well-separated prostate. A comparison between L. barlettai and the other known species of the genus is presented. The validity of these species is discussed, together with the suggestion that five valid species can be distinguished: L. genei, L. marmoratus, L. vermiformis, L. phiops, and L. barlettai. The characteristics of these species are tabulated.
New terrestrial amphipods (Crustacea: Amphipoda; Talitridae) from México and Central America
Authors: Lindeman Dorothy
Published: August 2008

Five new species, two new subgenera, and a new genus of terrestrial amphipods from the rain and cloud forests of México, Costa Rica, and Panamá are described: Caribitroides (Caribitroides) tuxtlensis n.sp., Caribitroides (Caribitroides) newtoni n.sp., Caribitroides (Mexitroides) pecki n.sp., Caribitroides (Mexitroides) chiapensis n.sp., and Cerrorchestia hyloraina n.gen., n.sp. A key to the species of forest leaf litter landhoppers of México and Central America is provided.
In vitro excystment of the metacercariae of Gynaecotyla adunca and Probolocoryphe uca (Microphallidae) from the fiddler crab, Uca pugilator
Authors: Dunn T. S. , Ownbey T. C. , Vannarath T.
Published: August 2008

A high rate and percentage of excystment of Probolocoryphe uca metacercariae occur at 40 °C in a low salt medium, in the absence of exogenous enzymes, indicating a largely active form of excystment. Exogenous trypsin is required for excystment of Gynaecotyla adunca metacercariae and it is presumed that excystment is largely a passive process. Saturated CO2 conditions promote excystment in this species, whereas high concentrations of pepsin, bile salts (especially deoxycholate), and extreme pH conditions have adverse effects on the process. Physicochemical factors operating in the in vitro excystment of the two microphallids are correlated with conditions presumed to prevail in the avian gut. Excysted metacercariae of both species begin egg production in vitro within several days. Such rapid development may be related to diverse definitive host capacities.
Foraging behaviour of Tree Swallows over acidified and nonacidic lakes
Authors: St. Louis Vincent L. , Breebaart Loes , Barlow Jon C.
Published: August 2008

We studied the effects of lake acidification on foraging behaviour of Tree Swallows (Tachycineta bicolor) at the Experimental Lakes Area in northwestern Ontario. Predictions suggest that food quantity and (or) food quality may be important factors related to the reproductive success of birds nesting near acidified bodies of water. Therefore, we investigated the extent to which Tree Swallows (aerial insectivores) use the affected ecosystem as a food resource base. We showed that breeding Tree Swallows foraged on the abundant chironomids emerging at their nest-site lakes before searching for food elsewhere. Chironomid abundance was greatest during the period when Tree Swallows produced their eggs, and declined significantly during periods when Tree Swallows incubated their eggs and fed their nestlings. The data suggest that the reproductive success of Tree Swallows nesting near lakes (and other aerial insectivores that primarily rely on emerging aquatic insects for food) is potentially at risk should changes in the quantity and (or) quality of emerging chironomids result from acidification.
Autogeny in Canadian Simuliidae (Diptera), with some experiments on rate of oögenesis
Authors: Davies D. M. , Györkös H.
Published: August 2008

Newly emerged females of 25 simuliid species were studied, 19 of which were maintained on dry sucrose and water to determine whether they could mature eggs autogenously. Females of nine species with reduced mouthparts and those of eight species with well-developed mouthparts proved to be autogenous, the latter group being presumably anautogenous for eggs cycles beyond the first. Females of the eight remaining species showed obligate anautogeny, requiring blood for any egg production. The literature indicated at least 19 Canadian simuliid species with obligate autogeny and at least 11 with facultative autogeny. The rate of ovarian development at different temperatures was examined in newly emerged females of 11 species and the completion of oögenesis varied from less than 2 days to 2 weeks in different species and in different females within species.
Regional analysis of mammal distributions among Canadian parks: implications for park planning
Authors: Glenn Susan M.
Published: August 2008

An unresolved question in conservation biology is whether a single large reserve will support more or fewer species than several smaller reserves adding up to the same total area, and how this affects species composition. Within 'mammal provinces' of Canada, several parks supported the same number of mammalian species, or more, than a single large park with the same area. The proportion of species that require undisturbed habitats increased with total area conserved. Human disturbances should be reduced in parks because these undisturbed-site species are unable to survive in disturbed environments not protected by a park system. An analysis of species distributions across parks indicated that not all small parks had the same composition. I therefore recommend establishing many parks in a biologically defined region and incorporating as much total area as possible. To aid in developing a strategy for placing parks across Canada, areas with high total mammalian richness and high richness of mammal species intolerant of disturbances are highlighted. Maps showing these areas are particularly useful because it is unlikely that several large parks will be established in every region and it is therefore important to identify the most diverse sites.
The haemoproteids of the avian orders Musophagiformes (the turacos) and Trogoniformes (the trogons)
Authors: Bennett Gordon F. , Peirce Michael A.
Published: August 2008

Haemoproteus montezi Travassos Santos Dias, 1953 of the turacos (family Musophagidae) is redescribed and a neohapantotype designated. Haemoproteustrogonis n.sp. of the trogons (family Trogonidae) is described.
Foraging by red bats (Lasiurus borealis): do intraspecific chases mean territoriality?
Authors: Hickey M. B. C. , Fenton M. B.
Published: August 2008

Thirteen individually marked Lasiurus borealis concentrated their foraging around lights where insect densities were higher than in surrounding dark areas. The marked bats foraged for an average of 113.1 min per night, attacked an insect every 30 s, and captured, on average, 40% of the insects they attacked. This translated to a nightly food consumption of 6.2 g of insects, or 42% of the bats' body mass. The bats selected large (body length >10 mm) moths significantly more often than predicted by their availability, but the foraging activity of the bats did not significantly deplete the patches of prey. Individual L. borealis preferred certain lights within the feeding site and intraspecific chases were common, but there was no significant relationship between prey density and the incidence of chases, and the chases did not result in individuals being excluded from the feeding areas. Our data support the hypothesis that individual L. borealis eavesdrop on the echolocation calls of conspecifics to identify the presence of prey and that conspecific chases at feeding sites are not evidence of territorial behaviour.
A new family of parasitic copepods, the Lernaeosoleidae (Poecilostomatoida), from demersal fishes in the Northwest Atlantic, with a description of Bobkabata kabatabobbus n.gen., n.sp. and a redescription of Lernaeosolea lycodis Wilson, 1944
Authors: Hogans William E. , Benz George W.
Published: August 2008

Bobkabata kabatabobbus n.gen., n. sp., collected from the flesh of Cottunculus thomsoni (Günther, 1882) from the Northwest Atlantic, is described. A species of similiar general habitus, Lernaeosolea lycodis Wilson, 1944, is redescribed from the holotype specimen. Bobkabata kabatabobbus n.gen., n.sp. and L. lycodis are placed in a new family, Lernaeosoleidae, based on the structure of the trunk and second antenna. The Lernaeosoleidae n.fam. appears most closely related to the poecilostomatoid family Chondracanthidae H. Milne Edwards, 1840.
Effects of winterkill on population structure, body size, and prey consumption patterns of pumpkinseed in isolated beaver ponds
Authors: Fox Michael G. , Keast Allen
Published: August 2008

Beaver ponds are a ubiquitous, but rarely studied, aquatic habitat that are subject to hypoxia and other catastrophic events that can affect fish populations. We examined the population dynamics and feeding ecology of pumpkinseeds (Lepomis gibbosus) inhabiting two isolated Ontario beaver ponds and adjacent Lake Opinicon to determine the persistence of and reasons for small body size in pond populations. Pumpkinseed populations fluctuated drastically in both ponds as a result of winterkills (from hypoxia and a decline in water level). These winterkills eliminated as many as 96% of the older pumpkinseeds and resulted in populations consisting mainly of age 0–2 individuals. Pond pumpkinseeds rarely survived to age 5, whereas lake conspecifics lived to age 8 or older. The diet of pond pumpkinseeds consisted mainly of chironomids, ephemeropterans, odonates, and molluscs, whereas lake pumpkinseeds ate mainly molluscs. The difference in diets was attributed mainly to differences in prey availability in the two habitats. Despite lower prey biomass and higher population density, pond pumpkinseeds grew as fast as, or faster than, their lake conspecifics owing mainly to early warming of water in the spring and the absence of bluegills and other major competitors. We conclude that small body size in pond pumpkinseed populations is due to high annual mortality and not stunted growth.
Mating strategies in male hooded seals (Cystophora cristata)?
Authors: Kovacs Kit M.
Published: August 2008

Male attendance of females with pups was monitored in individually marked hooded seals, Cystophora cristata, during the breeding seasons of 1988 and 1989. Two patterns of attendance were observed. Some males remained relatively sedentary and defended a single female as long as she remained on the ice. Other males were more mobile, attending several females for shorter periods of time. Because lactation in individual hooded seals lasts for only about 4 days and is followed immediately by mating, even sedentary males have the potential to mate with more than one female. Indeed, some of the marked sedentary males were observed with more than one female during the breeding season. These results are consistent with the hypothesis that male hooded seals are serially monogamous, i.e., polygynous, during a single breeding season.
Summer movement patterns of Arctic lemmings (Lemmus sibiricus and Dicrostonyx groenlandicus)
Authors: Rodgers Arthur R.
Published: August 2008

Several measures of movement based on livetrapping data were used to compare summer movement patterns of Lemmus sibiricus and Dicrostonyx groenlandicus in northern Canada. Distances moved by individuals of both species were greater when populations were intermediate in size than at high or low density. At intermediate density, males of both species moved farther than females. Seasonal movement patterns of the two species were similar. Coincident with reproductive periods in late July and late August, distances moved decreased in both species. Increased movements of both species followed periods of reproductive activity and also occurred at the end of each summer. These latter movements are related to seasonal changes in patterns of habitat use and diet in each species. These results suggest that dispersal is an important determinant of seasonal patterns of population change in both L. sibiricus and D. groenlandicus.
Surface areas of phocid seals
Authors: Innes S. , Worthy G. A. J. , Lavigne D. M. , Ronald K.
Published: August 2008

Standard morphometries and body surface areas were determined for 56 captive phocid seals. The mean Meeh constant, describing the relationship between maximum surface area (Amax) and body mass raised to the power 2/3 (m0.67), was 0.088 ± 0.011 m2∙kg−0.67. This value was not significantly different (P < 0.05) from the mean Meeh constant for 13 species of marine mammals (0.090 ± 0.018 m2∙kg−0.67), nor was it significantly different from the Meeh constants calculated for two samples of terrestrial mammals (0.097 ± 0.019 (N = 57) and 0.10 ± 0.013 m2∙kg−0.67 (N = 21)). The empirical allometric relationship between body mass and surface area for our phocid seals was log Amax = log 0.14 + 0.51 log m (R2 = 0.84). This relationship was not significantly different from that calculated for cetaceans, but was, however, significantly different from that calculated for terrestrial mammals. On average, surface areas of marine mammals (including pinnipeds, cetaceans, and the sea otter) were 23% smaller for their mass than those of terrestrial mammals.
Revision of the genus Clavellopsis Wilson, 1915 (Copepoda: Lernaeopodidae)
Authors: Kabata Z.
Published: August 2008

The morphology of 16 species of the genus Clavellopsis Wilson, 1915 (Copepoda: Siphonostomatoida: Lernaeopodidae), as presented by the literature, is examined and their generic affinity reconsidered. Seven nominal and one unnamed species are transferred to the genus Clavellotis Castro and Baeza, 1984. One species (C. parasargi) becomes the type of a tentatively proposed new genus, Pseudomixtio, one (C. laciniata) remains in the genus Clavellopsis, and one (C. johnii) is moved to the genus Neobrachiella Kabata, 1979. Lack of information does not allow any conclusion to be reached on the five remaining species.
Pregnancy determination in uncaptured feral horses based on steroid metabolites in urine-soaked snow and free steroids in feces
Authors: Kirkpatrick Jay F. , Shideler S. E. , Turner Jr. J. W.
Published: August 2008

Urine-soaked snow from 13 uncaptured feral mares was collected and measured without extraction for estrone conjugates (E1C) and nonspecific immunoreactive pregnanediol-3-glucuronide (iPdG) by enzyme immunoassays. The hormone values were indexed to creatinine (Cr). Mares that produced foals had urinary E1C values of 7.30 ± 1.39 (SE) μg/mg Cr versus 0.096 ± 0.084 μg/mg Cr for mares that did not produce foals. The difference was significant (P < 0.001). Nonspecific iPdG concentrations for mares producing foals was 167 ± 80.33 ng/mg Cr versus 7.04 ± 1.69 ng/mg Cr for mares that did not produce foals. The difference was significant (P < 0.0025). Urine samples collected directly from the ground from 34 uncaptured feral mares were measured for E1C and nonspecific progesterone metabolites and compared with fecal total estrogen concentrations in matched fecal samples, measured by means of radioimmunoassay. Both E1C and iPdG concentrations differed significantly (P < 0.001) between mares producing foals and those that did not. Mean fecal total estrogen concentrations for mares producing foals was 3.18 ± 0.70 ng/g feces versus 0.552 ± 0.08 ng/g feces for those that did not produce foals. The difference was significant (P < 0.001). The correlation coefficient between urinary E1C and fecal total estrogens was 0.928. The results indicate that both urine-soaked snow and fecal samples can be used to reliably assess pregnancy in uncaptured free-roaming feral horses.
Intra- and inter-specific variation in pupation behaviours of Drosophila from different habitats
Authors: Rodriguez Lucy , Sokolowski Marla B. , Carton Yves
Published: August 2008

Isofemale strains of Drosophila melanogaster and D. simulans were collected from wet and dry habitats in Tunisia. These strains were used to study the effect of habitat (collection site) and laboratory rearing temperature on larval pupation behaviour of these species. Results showed that D. melanogaster isofemale strains from the wet habitat pupated significantly higher in vials than those from the drier habitat. In contrast, the pupation behaviour of D. simulans isofemale strains was not affected by habitat type. Significant intraspecific variation in pupation behaviour was found for both species from both habitats. The distance pupated away from food in vials was positively correlated to the distance pupated from fruit in a field-like assay. Plasticity for pupation height was found at 16 and 32 °C for both species. Greater between-strain variation in pupation height was found for D. melanogaster at 32 °C and for D. simulans at 16 °C. The patterns of interspecific differences in larval pupation height paralleled those previously reported for adult behaviour patterns in these species.
Repeatability of wing molt timing of mallards in relation to breeding
Authors: Leafloor James O. , Batt Bruce D. J.
Published: August 2008

We measured dates of first egg laid, last egg laid, last incubation and start of wing molt for 80 pairs of captive mallards (Anas platyrhynchos) from 1973 to 1975. We calculated annual repeatability of these variables within individuals as [Formula: see text], where [Formula: see text] is the among-individuals variance and s2 is the within-individuals variance from one-way ANOVA. We also evaluated the relationship between breeding chronology and timing of wing molt in individuals. Initiation of egg laying was consistent over 3 years (R = 0.66), but last date of incubation was more variable (R = 0.29). Date of wing molt initiation was also fairly consistent in individual males (R = 0.66) and females (R = 0.62). Date of wing molt initiation of males was unrelated to the date of their mate's last fertile egg (P > 0.05). Some variation (r2 = 0.07−0.18) in start of wing molt by females was explained by date of last incubation. Yearling females stopped laying eggs earlier (t = 3.49, P < 0.05) and began wing molt earlier (t = 2.61, P < 0.05) than in their 2nd year, suggesting that some variation in breeding and wing molt chronology was related to age and (or) breeding experience.
Sexual dimorphism and predaceous feeding habits of the waterstrider Gerris remigis Say (Heteroptera: Gerridae)
Authors: McLean Edward B.
Published: August 2008

The feeding habits of Gerris remigis were examined in a southeastern Ontario stream. Gerrids with prey items were collected from two pools along a 15-m length of the site. The size distribution of potential prey available in the surface drift during the survey was estimated. Gerrid prey consisted mainly of terrestrial insects; coleopterans, dipterans, homopterans, and hymenopterans represented the predominant orders. The median size of prey taken by all gerrids was significantly larger than that available in the surface drift. A sexual dimorphism in gerrid body size was found. The length of prey taken did not differ between the sexes; however, the diet of the larger bodied females consisted of prey with a greater median body width than the diet of smaller males. Females also took a greater size range of prey. These results support a size-dependent predation model which predicts that the upper size range of prey that can be successfully captured is correlated with predator size.
Geographic variation in hybrid fertility in the field crickets Gryllus integer, G. rubens, and Gryllus sp.
Authors: Cade William H. , Tyshenko Michael G.
Published: August 2008

Hybridization was attempted between three geographically separated field cricket populations having males that produce distinct songs. Gryllus integer from central Texas and G. rubens from Arkansas produced many offspring in both reciprocal crosses. Gryllus sp. from New Mexico also produced hybrid offspring in matings with G. integer and G. rubens but at a very low frequency and only in crosses where the female was Gryllus sp. In previous experiments, G. integer from California was unable to hybridize with G. integer from Texas and G. rubens.
Activity budgets of greater snow geese in fall
Authors: Giroux Jean-Francois , Bédard Jean
Published: August 2008

We examined whether the fall activity budgets of greater snow geese (Chen caerulescens atlantica) vary between years and sites by comparing time-budget data gathered from 1982 to 1984 at the Montmagny and Cap-Saint-Ignace sanctuaries in Quebec. Feeding and resting accounted for more than 70% of the activities during the daylight period. At Cap-Saint-Ignace, geese spent less time feeding and more time resting during the 2nd year of the study, whereas no such annual variation was found at Montmagny. Snow geese also spent more time feeding and less time resting at Montmagny than at Cap-Saint-Ignace. These differences are discussed in relation to energy requirements, quality of feeding sites, temperature, and disturbance associated with hunting.
Morphological and biochemical characterization of the trypanosomatids Crithidia desouzai and Herpetomonas anglusteri
Authors: Motta Maria Cristina M. , Cava Antonio M. Sole , Silva Paulo M. F. , Fiorini João E. , Soares Maurílio J. , Souza Wanderley De
Published: August 2008

Two species of trypanosomatids, Crithidia desouzai and Herpetomonas anglusteri, were recently isolated from Diptera in Minas Gerais, Brazil. The Crithidia species was found to harbor bacterium-like endosymbionts in the cytoplasm. To biochemically characterize these two species of trypanosomatids, and to try to verify the evolutionary meaning of the presence of endosymbionts, an electrophoretic study was undertaken whereby the two species were compared with eight other species in the same family. Horizontal 12.5% starch gel electrophoresis was used to resolve the isozymes of eight enzyme systems: acid phosphatase, glucose-6-phosphate dehydrogenase, hexokinase, malate dehydrogenase, malic enzyme, 6-phosphogluconate dehydrogenase, phosphoglucose isomerase, and phosphoglucomutase. Ten other enzyme systems were assayed without yielding any reproducible activity. The isozymes observed were conservatively interpreted as being due to the activity of 44 different alleles. All species studied differed in at least one enzyme system. The phenetic (Jaccard similarity index, UPGMA grouping) analysis produced a tree in which the species of Crithidia and Herpetomonas clustered separately, forming monophyletic groupings. All the endosymbiont-bearing species formed a monophyletic cluster, indicating that the presence of bacterium-like endosymbionts may be a synapomorphy of that group, and may represent, therefore, a unique event in the evolution of the genus.
Effect of a sprint-training protocol on acceleration performance in rainbow trout (Salmo gairdneri)
Authors: Gamperl A. Kurt , Schnurr Dan L. , Stevens E. Don
Published: August 2008

Fast-start acceleration performance of rainbow trout (Salmo gairdneri) was measured after 9 weeks of sprint training (30°s duration, every 2nd day). Response latency and time required to complete the first two stages of a fast start were unaffected by the sprint-training protocol. Maximum acceleration (trained 1985 ± 176 (SE) cm/s2; control 1826 ± 144 cm/s2) and maximum velocity (trained 130 ± 7 cm/s; control 134 ± 14 cm/s) were also not significantly different following training. However, trained fish reached high rates of acceleration before control (untrained) fish. Thus, acceleration was higher in trained fish from 20 to 35 ms postshock. When fish are separated by start type, trained fish consistently had greater acceleration than control fish between 30 and 45 ms postshock. Alterations in fast-start performance due to sprint training may improve predator avoidance ability. Sprint training did not change critical swimming speed as measured using two separate protocols.
Parasite evolutionary events inferred from host phylogeny: the case of Labeo species (Teleostei, Cyprinidae) and their dactylogyrid parasites (Monogenea, Dactylogyridae)
Authors: Guégan Jean-François , Agnèse Jean-François
Published: August 2008

Independent phylogenies of West African Labeo (Teleostei, Cyprinidae) and their gill parasites of the genus Dactylogyrus (Monogenea, Dactylogyridae) are proposed. The phylogeny of Labeo is based on allele characters, whereas the phylogeny of the parasites is based on morphometric features. The comparison of host and parasite phylogenies did not correlate completely with predictions made by using Fahrenholz's rule. Parasites encountered on L. coubie and L. senegalensis seem to have evolved in parallel with their host, or by sequential colonizations between these two related hosts. Whatever the host–parasite evolutionary events between L. coubie and L. senegalensis and their specific dactylogyrids, two hypotheses of host switching on L. parvus and L. roseopunctatus are probable, reflecting a close ecological relationship between the various host taxa. Dactylogyrus brevicirrus and D. nathaliae, found on the gills of L. parvus and L. roseopunctatus, respectively, are each the sister-species of a living parasite on L. coubie. The notions of parallel evolution (or coevolution in a broader sense) and host switching with speciation are discussed. Finally, Fahrenholz's rule is analyzed as a forecasting tool that can be used in systematics.
Microclimate variability and the eurythermic nature of goldenrod gall fly (Eurosta solidaginis) larvae (Diptera: Tephritidae)
Authors: Layne Jr. Jack R.
Published: August 2008

Four insect species inhabit ball galls on goldenrod plants (Solidago sp.) for several months of the year. These sites are highly exposed and conceivably undergo wide fluctuations in temperature on a daily basis. I recorded temperature profiles for galls in western New York between September and November. The capacities of a gall inhabitant (Eurosta solidaginis larvae) to endure high temperature and freezing were also recorded during this period. I noted considerable and concurrent variation in air temperature and gall temperature. Diurnal radiant heating augmented changes in gall temperature so that their daily variations often ranged between 25 and 29 °C. From September to November, Eurosta larvae tolerated 24-h exposures to 35.5 °C and freezing at −6.5 °C. In the latter case, this occurred despite the lack of any appreciable accumulation of cryoprotectants in September and October. Greater freeze tolerance was gained by November (100% survival at −15.5 °C), when hemolymph osmolality increased 60% to 722 mosmol. This study demonstrates the extremely eurythermal nature of ball galls and the highly developed capacities of gall inhabitants to survive extreme temperatures.
Anural development of the ascidian Molgula pacifica (Huntsman)
Authors: Bates William R. , Mallett Joan E.
Published: August 2008

Molgula pacifica embryos exhibit anural development in which embryogenesis proceeds directly to the development of a juvenile, without the development of a tailed larva. The purpose of this study was to investigate the key events that are responsible for the development of M. pacifica juveniles. The results of the present investigation indicate that the timing and spatial rearrangements of the egg cytoplasm that occur after fertilization (termed ooplasmic segregation) are similar in M. pacifica eggs as compared with those that occur in typical urodele species. These observations suggest that the mechanism that is responsible for the urodele pattern of ooplasmic segregation was conserved during the evolution of anural species. The cleavage patterns displayed by M. pacifica embryos up to the eight-cell stage were similar to those exhibited by urodele embryos. However, gastrulation in M. pacifica embryos differed from the typical urodele mode of gastrulation. The mode of gastrulation exhibited by M. pacifica embryos is likely a consequence of their eggs containing a greater quantity of yolk than the less yolky eggs of species more commonly studied. In the second part of this investigation, ampullar development, structure, and function were studied. Two conclusions were made from these studies. First, the extracellular matrix materials comprising the tunic are secreted by the epidermal ampullar cells. Second, a shift in the timing of ampullar rudiment development in M. pacifica embryos suggests the possibility of a heterochronic mechanism of evolutionary change within the epidermal cell lineage.
Redescription of Ergasilus labracis (Krøyer, 1864) (Copepoda: Poecilostomatoida), a parasite of anadromous fishes from the east coast of North America
Authors: Hogans W. E.
Published: August 2008

Ergasilus labracis (Krøyer, 1864), a parasite of anadromous fishes from the east coast of North America, is redescribed. Descriptions and figures of the structure of the appendages and mouthparts, previously unreported, are presented. A review of the literature on E. labracis and new host and locality records are included.
Genetic, maternal, and tank determinants of growth in hatchery-reared juvenile Arctic charr (Salvelinus alpinus)
Authors: March B. G. E. de
Published: August 2008

The relative importance of genetic, maternal, and tank effects on the growth of juvenile Arctic charr (Salvelinus alpinus) was examined in an incomplete factorial mating design (4 dams × 4 sires) with stock from the Fraser River, Labrador, Canada. Egg size and hatching success were related only to dams. Mean weights at 30, 75, and 125 days after swim-up, logistic growth curve parameters describing the change in the mean weight, and a measure of condition, all described within families, were significantly related to both dams and sires and were also correlated with each other. The early patterns of significant differences due to dams and sires changed after approximately 125 days. After this time the mean weights in tanks, although still increasing, became negatively correlated with their coefficients of variation (CV), which had changed only slightly with time. The magnitude of the CVs could not be attributed to specific parents. The changed patterns of differences in the means with time suggested that either (i) the social climate within tanks, measured as the CV, affected the growth of all fish even though they were neither crowded nor underfed, or (ii) an individual's ability to grow was dependent not only on its phenotype (initial weight) but also on its genotype, expressed only in data from sibs. These laboratory results may relate to unique distribution and fitness characteristics of natural Arctic charr populations.
Hatching asynchrony, chick care, and adoption in the common tern: can disadvantaged chicks win?
Authors: Morris Ralph D. , Woulfe Michelle , Wichert G. D.
Published: August 2008

In 1987 and 1988, common tern (Sterna hirundo) chicks at a colony near Port Colborne, Ontario, were individually colour banded according to known hatch order. Intraclutch hatch intervals produced size disparities among chicks at brood completion; third-hatched chicks were significantly lighter and at a significant survival disadvantage compared with their earlier-hatched siblings. There were differences in feeding rates according to hatch order and many third-hatched chicks obtained fewer or no feedings during our periods of observation. Sixty-five chicks known to have abandoned their home broods gained acceptance into foreign broods. Chicks that remained in the foreign brood for more than 2 days (average residency 11.9 ± 5.3 days; n = 26) were fed and brooded by the foster parents, were on average older than the youngest resident chick, but were not always the last hatched in their home brood. Conversely, chicks that were in a foreign brood for less than 2 days were no different in age from the youngest resident chick. Survival and fledging success was highest for chicks accepted into two chick broods in which they were older than the resident second chick; in effect, the adoptee became the second chick. Parents that accepted a foreign chick for more than 2 days experienced a seasonal fitness loss compared with nonadopting parents. As the only viable option available to them, selection favours movement away from home broods by chicks that may be disadvantaged there.
Ammonia dynamics during and after prolonged emersion in the freshwater clam Corbicula fluminea (Müller) (Bivalvia: Corbiculacea)
Authors: Byrne Roger A. , Dietz Thomas H. , McMahon Robert F.
Published: August 2008

Hemolymph ammonia content during emersion and ammonia fluxes on reimmersion were examined in the freshwater bivalve Corbicula fluminea (Müller). Hemolymph ammonia levels remained at pre-emersion levels over a 5-day emersion period at 25 °C, but thereafter levels increased prior to death. On resubmergence after 3 days emersion, the initial rates of ammonia excretion were low and took 15 h to reach maximum levels. Duration of emergence did not affect postemergence ammonia excretion rates in individuals emersed for less than 3–4 days. These results indicate a lack of ammonia accumulation in aerially exposed specimens. Rather, C. fluminea appeared to suppress protein catabolism during emergence and avoided ammonia accumulation. Death on emergence occurred coincidentally with an increase in ammonia accumulation. After reimmersion, the delay in development of ammonia efflux maxima may represent metabolic "switching" from catabolism dominated by nonprotein energy stores to one partially supported by protein. Suppression of protein catabolism in air is an adaptation to the prolonged and unpredictable emergence not previously reported for any freshwater species.
Influence on the variation in initiation of breeding in Peromyscus maniculatus
Authors: Sharpe Sean T. , Millar J. S.
Published: August 2008

Correlates of the initiation of breeding by female Peromyscus maniculatus borealis (Mearns) were examined to test the hypotheses that asynchronous breeding was related to age, weight, matriline, and nest-site habitat. Life-history data were collected by mark–recapture techniques and by monitoring natal nests over two breeding seasons in 1985 and 1986. Timing of initiation of breeding was related significantly to nest-site habitat and age, but not to matriline or weight. At approximately the same altitude, females nesting in dry rocky stream beds bred first, followed by those in open rock fields, then shrub areas, and last in subalpine forest. Youngest animals bred first in all habitats, although the relationship between age and initiation date was weak. Habitat effects appeared to be primarily related to microclimatic effects. The influence of habitat on the timing of initiation of breeding also had consequences for reproductive success, total reproductive output, and survival. Reproductive success of first litters was greatest for females nesting in rocky stream beds in the spring and least for females nesting in shrub and forest habitats. The apparent advantages of early breeding in rocky stream beds were offset by greater overwinter mortality.
Larval settlement of Sabellaria cementarium Moore, and comparisons with other species of sabellariid polychaetes
Authors: Pawlik Joseph R. , Chia Fu-Shiang
Published: August 2008

Tube-building marine worms of the polychaete family Sabellariidae exhibit a wide range of settlement strategies; the larvae of some species settle with near-absolute specificity on the sandy tubes of conspecific adults to build extensive reefs, while others are not gregarious and construct solitary or paired tubes. Sabellaria cementarium forms aggregations in some localities, but it is nongregarious throughout much of its range. Larvae of S. cementarium were competent to metamorphose in 25 days at 15 °C, much sooner than previously reported and within the range of other sabellariids cultured under the same conditions. In two of three experiments, there were no significant differences in larval settlement on conspecific tube sand versus control sand or tube sand extracted with organic solvents, suggesting that this species does not aggregate in response to a chemical cue. Settlement was not enhanced in response to free fatty acids, naturally occurring inducers of settlement for two reef-forming sabellariids, Phragmatopoma lapidosa lapidosa and P. l. californica. In reciprocal assays, larvae of S. cementarium and P. l. californica did not significantly discriminate between conspecific and heterospecific tube sand; yet, where they co-occur, the tubes of the former species are not found in aggregations of the latter. The two species were not interfertile, although one cross resulted in ~ 14% fertilization with larvae dying shortly after hatching. The processes by which larvae of S. cementarium avoid settlement on the tubes of P. l. californica (and the reverse for the latter species) remain unclear.
Microhabitat selection and adaptation of feather mites (Acari: Analgoidea) on murres and kittiwakes
Authors: Choe Jae C. , Kim Ke Chung
Published: August 2008

The adaptations and spatial distributions of three species of analgoid feather mites on Alaskan seabirds were studied: Alloptes conurus (Trouessart) on common and thick-billed murres and A. obtusolobus Dubinin and Laronyssus martini (Trouessart) on black-legged and red-legged kittiwakes. The mites exhibited a number of morphological features that presumably reduced their resistance to airflow. They were attached to the distal side of the barb in the trailing vane on the ventral surface of the flight feathers. This highly localized distribution pattern was consistent with general predictions based upon aerodynamic considerations. Alternatively, preening by the host bird may have limited the mites to that particular microhabitat.
Morphology and histology of tarsal glands in bumble bees of the genera Bombus, Pyrobombus, and Megabombus
Authors: Pouvreau A.
Published: August 2008

The last tarsal segment and pretarsus of adult bumble bees are described. The tarsal gland on the fifth tarsomere of each leg in all individuals of a colony consists of simple glandular epithelium surrounding a reservoir in which its secretory products accumulate. Movement of the pretarsus in and out of the fifth tarsomere helps to discharge the secretion of the gland onto the ventral surface of the arolium. Study of the fine structure of the glandular cells reveals the presence of cytoplasmic organelles involved in secretion. The apical surface of the cells bears numerous microvilli associated with a smooth endoplasmic reticulum. Ergastoplasm is mainly located in the basal region. The spherical or ovoid nucleus is generally located basally and the cytoplasm contains uniformly distributed Golgi complexes, ribosomes which vary in number from one area to another, more or less electron-dense multivesicular bodies, mitochondria, and pinocytotic vesicles and coated vesicles in the cytoplasm of the apical area. Interdigitations and desmosomes contribute to the cohesion of cells within the epithelium. The tarsal gland of bumble bees is compared with that of other insects, and the function of its secretion is considered.
Endocrine and electrophoretic profiles during pregnancy and nonpregnancy in captive female black bears
Authors: Hellgren E. C. , Vaughan M. R. , Gwazdauskas F. C. , Williams B. , Scanlon P. F. , Kirkpatrick R. L.
Published: August 2008

We collected blood samples from captive adult female black bears (Ursus americanus) at 10-day intervals during September–March in 1987–1988 and 1988–1989 (6 bears/year) in Virginia. Ten of 12 bears hibernated for an average of 92 days. Serum progesterone concentrations slowly increased from 2 to 7 ng/mL during October and November, then increased 2- to 3-fold 58 ± 5 days before parturition in five bears that produced cubs. After the implantation peak, progesterone gradually declined, reaching undetectable levels 1–2 days postpartum. Similar but more variable progesterone profiles were observed in five of seven bears that did not produce any observed cubs. Progesterone was also assayed in 38 active wild black bears to relate to reproductive status in the den. Results suggested that pseudopregnancy, implantation failure, or fetal resorption may occur in black bears. Mean serum estradiol-17β concentrations were 18.5 ± 0.7 (SE) pg/mL in captive bears, with pregnant bears showing no change between implantation and parturition. Polyacrylamide gel electrophoresis of serum proteins was not a reliable indicator of pregnancy.
Life history and distribution of mayflies (Ephemeroptera) in some acid streams in south central Ontario, Canada
Authors: Giberson Donna J. , Mackay Rosemary J.
Published: August 2008

Life histories and distribution of mayflies (Insecta: Ephemeroptera) were investigated in 11 streams in south central Ontario that ranged from highly acidic to circumneutral. At least 29 mayfly species were recorded from the streams, with 16 common enough for life history analysis. Mayfly distribution and diversity were correlated with pH regime and stream size. No mayflies were found in the smallest, most acid stream, and numbers of mayfly species and their relative abundances generally increased with both increasing stream size and stream pH. Incorporation of life cycle information with distributional data enabled us to determine the precise stream-water pH range encountered by different mayfly life stages in the study streams. Generally, during the period of greatest acid stress in the streams (pH depressions associated with spring snowmelt) the mayflies were present in large or dormant stages, which are believed to be more tolerant of lowered pH.
Organization of the adluminal and retractor cells in the coelomic lining from the tube foot of a phanerozonian starfish, Luidia foliolata
Authors: Cavey Michael J. , Wood Richard L.
Published: August 2008

The coelomic lining in the tube feet of the phanerozonian starfish Luidia foliolata is a complex pseudostratified myoepithelium consisting largely of flagellated adluminal cells and myofilament-bearing retractor cells. The adluminal cells, joined by zonular intermediate and septate junctions, line the water–vascular canal. Basal processes of the adluminal cells penetrate the underlying layers of retractor cells to terminate as bulbous pedicels at the myoepithelial basal lamina. The longitudinally oriented retractor cells, linked by macular and fascial intermediate junctions, also direct processes obliquely to the basal lamina for anchorage. In keeping with its myoepithelial classification, the coelomic lining of the tube foot is devoid of connective tissue. The organization of the coelomic lining in this primitive species has not substantively improved our understanding of the events of excitation–contraction coupling. Both the coelomic lining and the podial connective tissue lack nerves, and there is no ultrastructural evidence of communicating (gap) junctions between the retractor cells. The sarcoplasmic reticulum of a retractor cell is a plexiform network of agranular cisternae lodged between the contractile apparatus and the sarcolemma. Peripheral couplings between the sarcoplasmic reticulum and the sarcolemma can be identified in ultrathin sections by the presence of electron-dense plaques in the sarcoplasmic gaps between the apposed membranes. In freeze-fracture replicas, the placement of these structural couplings is correlated with aggregations of large intramembranous particles over regions of cisternal confluence. Conceptual problems in understanding excitation–contraction coupling in a modern starfish are compounded in this primitive representative by the presence of many more layers of retractor cells and by a burrowing life-style which requires the tube feet to respond in a rapid, highly coordinated manner.
The developmental stages of Lepeophtheirus salmonis (Krøyer, 1837) (Copepoda: Caligidae)
Authors: Johnson S. C. , Albright L. J.
Published: August 2008

Lepeophtheirus salmonis (Copepoda: Caligoida) is an economically important marine ectoparasite of wild and pen-reared salmonids. The morphology of its developmental stages is described and compared with that of other species of Lepeophtheirus and Caligus. The development of L. salmonis is very similar to that reported for other Lepeophtheirus species. The appendages generally attain the adult condition and the sexes become distinguishable later in development than in Caligus species. At all developmental stages except the nauplius, L. salmonis can be distinguished from the co-occurring Caligus clemensi.