bluuebunny/crossref_metadata_2025 huggingface dataset:
DESCRIPTIONS OF SIX NEW SPECIES OF GARMANIA NESBITT AND LASIOSEIUS BERLESE (ACARINA: ACEOSEJIDAE)
Authors: Chant D. A.
Published: April 2011

Six new species of aceosejid mites are described and figured: Lasioseius (Lasioseius) allii from onion bulbs imported from South Africa to New York; L. (Paragarmania) helvetius from pear bark, Lausanne, Switzerland; L. (P.) bakeri from dried prunes and peaches imported to California from Chile, and on cantaloupe fruit imported to Arizona from Mexico; Garmania curtipilis from sorghum imported to Texas from Mexico; G. longipilis from cativo logs imported to North Carolina from Costa Rica; and G. utahensis from decayed tomato fruits in Utah. A short diagnosis is given for each species.
A NEW HOST OF ENTAMOEBA INVADENS RODHAIN, 1934
Authors: Meerovitch Eugene
Published: April 2011

A strain of Entamoeba invadens has been isolated for the first time from a natural infection in a painted turtle, Chrysemys picta. Infection experiments with this strain have corroborated the earlier observations on the high pathogenicity of E. invadens in snakes, but not in turtles. This, together with the fact that E. invadens in the past had been isolated only from captive snakes, which might have become infected in captivity from turtle carriers, suggests that E. invadens is a natural, non-pathogenic parasite of turtles.
STUDIES ON DIPTEROUS PARASITES OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA.TORTRICIDAE): VI. PHOROCERA INCRASSATA SMITH (DIPTERA:TACHINIDAE)
Authors: Coppel H. C.
Published: April 2011

Phorocera incrassala Smith, which was transferred from Western to Eastern Canada for release against the spruce budworm, Choristoneura fumiferana (Clem.), deposits microtype eggs on leaves, which are later ingested by the host. Eggs hatch immediately after ingestion, but the parasite does not develop beyond the first instar until the host pupates. The larva then develops rapidly, matures in 10 days, and forms its puparium within the host pupal case. The adult emerges in 12 to 14 days. No information is available on the overwintering habits. Among the important characters for identifying the immature stages of P. incrassala are the buccopharyngeal apparatus and the anterior and posterior spiracles.
NEMATODES FROM VARANID LIZARDS OF BORNEO. A DESCRIPTION OF ABBREVIATA BORNEENSIS N. SP. (NEMATODA: PHYSALOPTERIDAE) AND RECORDS OF TWO OTHER SPECIES
Authors: Schad G. A.
Published: April 2011

Three nematodes are recorded from varanid lizards of Borneo. The nematodes are Amplicaecum varani, Tanqua tiara, and Abbreviata borneensis n. sp.
STUDIES ON STRONGYLOIDES OF PRIMATES: V. SYNONYMY OF THE SPECIES IN MONKEYS AND APES
Authors: Premvati
Published: April 2011

A study of the comparative morphology and life history of S. fülleborni, S. cebus, and S. simiae in both the parasitic and free-living generations under different environmental conditions, and their comparison with the free-living stages from faeces of Old World and New World primates has led to the conclusion that the three species should be synonymized into one, for which the name Strongyloides fülleborni von Linstow (1905) has priority.
Reproductive behavior of ninespine sticklebacks (Pungitius pungitius (L.)) in South Bay, Manitoulin Island, Ontario
Authors: McKenzie Joseph A. , Keenleyside Miles H. A.
Published: April 2011

The reproductive behavior of aquarium-held and free-living ninespine sticklebacks was studied at South Bay, Manitoulin Island, Ontario. In general their behavior resembles that of the Northwestern European Pungitius, which has been described in the literature, but several differences were discovered. The European form breeds in quiet, weedy streams, whereas the South Bay form breeds in rocky, barren, often turbulent lakeshores. The breeding males of the South Bay form have a black ventral patch that has not been described for the European form. Like Gasterosteus, the South Bay form nests on the substrate, unlike the European form, which nests in weeds. Differences in the details of nest building, agonistic, courtship, and parental behavior have been discussed in terms of adaptations to specific breeding habitats.
Toxic effect of elemental phosphorus on L-cells cultivated in suspension
Authors: Li M. F. , Traxler G. S. , Langille L. M.
Published: April 2011

The effects of elemental phosphorus upon cell replication and cellular morphology were tested on L-cells grown in spinner culture. The cell replication was completely inhibited by the presence of elemental phosphorus in the culture medium at 1.25 mg/1. At 0.31 mg/1, 74% inhibition of the cell replication was observed. A calculated correlation coefficient between the percentage inhibition and the phosphorus concentration was valid at the 1% level.The phosphorus significantly altered the cellular morphology. The affected cells showed ballonization, loss of stain-binding capacity, disintegration of cytoplasm, enlarged nuclei with vacuolated nucleoli, and formation of multiple nucleated giant cells. A possible sequence of the changes was discussed.
Effect of methyl testosterone on the ovary and secondary sex characters of the hypophysectomized juvenile guppy, Poecilia reticulata Peters
Authors: Pandey S.
Published: April 2011

Treatment with methyl testosterone produces no change in the ovaries of guppies which were hypophysectomized before gonad differentiation but does induce a marked development of the oviducts with the appearance of typical male secondary sex characters. Sex ratios remained unchanged in hypophysectomized juveniles treated with methyl testosterone.
Intraclutch egg-weight apportionment and chick survival in Caspian terns
Authors: Quinn James S. , Morris Ralph D.
Published: April 2011

Egg-weight apportionment patterns and chick survival were investigated in two-egg clutches of Caspian terns(Sterna caspia) in the Great Lakes. First-laid eggs (A eggs) were typically heavier than second-laid eggs (B eggs) and hatched an average of 1.8 days earlier. The A-egg fraction of total clutch weight increased with total clutch weight. Increased egg weight did not increase the probability of hatching, but did increase the fledging success of A chicks: specifically, A eggs that produced fledglings were significantly heavier than those whose chicks did not fledge. No such relationship held for B eggs. The main effect of B-egg weight was in prolonging life: excluding those few that fledged, egg weight was correlated significantly with age at mortality. Chick mortality appeared to be due mainly to starvation and gull predation. We suspect that greater body size and (or) behaviour associated with body size helps chicks escape risk from gape-limited predators. The hatching of A eggs had a negative effect on the survival of B chicks, but the reverse was not true. B offspring may act as insurance against the loss of A siblings. The potential benefit to parents of investing more in B eggs appears to be constrained by sibling competition with A chicks, which often results in brood reduction. The pattern of egg-weight apportionment in eggs is interpreted as a parental response to the differences in the reproductive values of asynchronously hatching chicks.
The effect of Trichinella pseudospiralis infection on the reproductive success of captive American kestrels (Falco sparverius)
Authors: Saumier Michèle D. , Rau Manfred E. , Bird David M.
Published: April 2011

Trichinella pseudospiralis infections reduced the reproductive success of captive American kestrels (Falco sparverius). Infected birds manifested a delayed onset of egg laying (day 31) when compared with uninfected controls (day 23). All control females continued to produce eggs after the first three were removed, but only 66.7% of the infected females managed to do so. Consequently, infected birds produced a mean total of only 4.9 eggs, as compared with 7.1 eggs for the controls. Breakage (29.0%) and embryo mortality (40.0%) were the major sources of egg loss among infected birds. The corresponding losses among control birds were 1.6 and 4.7%, respectively. Consequently, control birds produced an average of 2.1 hatchlings per pair, whereas infected birds produced only 0.6.
Ultrastructure of the female reproductive organs (ovary, vitellaria, and Mehlis' gland) of Halipegus eccentricus (Trematoda: Derogenidae)
Authors: Holy Jon M. , Wittrock Darwin D.
Published: April 2011

The female reproductive organs (ovary, vitellaria, and Mehlis' gland) of the digenetic trematode Halipegus eccentricus were studied by transmission electron microscopy. Oocytes entered diplotene while in the ovary and produced cortical granules and lipid bodies. Vitelline cells produced large amounts of eggshell protein but no yolk bodies. Two types of Mehlis' gland secretory cells were present, distinguishable by the morphology of their rough endoplasmic reticulum, Golgi bodies, and secretory bodies, and by the persistence of recognizable secretory material within the ootype lumen after exocytosis. In an attempt to standardize the nomenclature regarding the cell types of the Mehlis' gland, a classification that takes into account these four criteria is proposed. Two basic types of Golgi body organization were noted for the cells of the female reproductive system: a stack of flattened cisternae (Mehlis' gland alpha cells) and spherical Golgi bodies with vesicular cisternae (oocytes, vitelline cells, and Mehlis' gland beta cells).
Developmental stages of Sphaerospora ohlmacheri (Whinery, 1893) n.comb. (Myxozoa: Myxosporea) in the renal tubules of bullfrog tadpoles, Rana catesbeiana, from Lake of Two Rivers, Algonquin Park, Ontario
Authors: Desser Sherwin S. , Lom Jǐrí , Dyková Iva
Published: April 2011

Pseudoplasmodia and mature spores of Sphaerospora ohlmacheri (Whinery, 1893) n.comb. were found in the renal tubules and in the space of the Bowman's capsule of 2nd-year tadpoles of the bullfrog, Rana catesbeiana. Fresh spores and the sporogenic stages of S. ohlmacheri from tissue imprints and histological sections are described and illustrated. Dystrophic changes of renal tubule cells characterized by degeneration associated with hyaline droplets often accompanied the presence of the parasite. Features of the genera Leptotheca, Wardia, and Sphaerospora are discussed.
Resource use by unexploited sympatric bobcats and coyotes in Oregon
Authors: Witmer G. W. , deCalesta D. S.
Published: April 2011

Unexploited populations of bobcats (Felis rufus) and coyotes (Canis latrans) were studied in the Elliott State Forest, Douglas and Coos counties, Oregon, from September 1981 to July 1982. A total of 633 radio locations of six bobcats and five coyotes were used to determine home ranges, activity, and habitat-use patterns. Twenty-five prey items were identified in bobcat and coyote scats. Diets of the two species were similar (overlap values were greater than 0.92 for all seasons). Mountain beaver (Aplodontia rufa) remains occurred in over 70% of the scats from both species. Home ranges for radio-collared animals averaged 14 km2 for male coyotes, 12 km2 for female coyotes, 11 km2 for one male bobcat, and 2 km2 for female bobcats. Bobcat and coyote home ranges overlapped in time as well as space. Radio-collared bobcats were detected on occasion within the same clear-cut sites concurrently with radio-collared coyotes, and daily activity patterns were nearly identical between the two predators. Bobcats and coyotes used open areas during nightly hunting activities and retired to forested areas during the day. Coyotes used grassy, more open clearings whereas bobcats favored brushy sites.
Repeat sexual maturation of precocious male chinook salmon (Oncorhynchus tshawytscha) transferred to seawater
Authors: Bernier Nicholas J. , Heath Daniel D. , Randall David J. , Iwama George K.
Published: April 2011

Precocious sexual maturation in salmonid parr occurs under both wild and culture conditions. We investigated the possibility of repeat maturation in precocious chinook salmon parr from the Nicola River, British Columbia. Precocious and immature (control) yearling parr were reared in fresh water from March 1990 to mid-June, and then transferred to salt water (29–30 ppt) until September 1990. The precocious parr were significantly larger than the controls from March to July and there were no differences in relative growth rate between the groups throughout the study. Total mortalities were 45.7 and 5.9% for precocious and control fish, respectively. All of the precocious, but none of the control fish, produced milt in March in fresh water. None of the fish produced milt soon after the transfer to salt water in June, but all precocious fish and 18.8% of the controls produced milt in September. There were no significant differences in the average plasma concentrations of Na+, Cl−, and cortisol between groups in September, suggesting that both precocious parr and control groups were saltwater competent. These data demonstrate that male precocious chinook salmon parr have the physiological capability to mature more than once in seawater.
Sphaeridiotrema globulus (Rudolphi, 1814) (Digenea): evidence for two species known under a single name and a description of Sphaeridiotrema pseudoglobulus n.sp.
Authors: McLaughlin J. Daniel , Scott Marilyn E. , Huffman Jane E.
Published: April 2011

Experimental infection of domestic ducklings with metacercariae believed to be those of Sphaeridiotrema globulus from snails in Quebec, Canada, and New Jersey, U.S.A., revealed that there are two species known under this name. Study of museum specimens has confirmed that the New Jersey specimens represent the original S. globulus: the specimens from Quebec represent a new species. The two species can be separated reliably on the basis of egg size: S. globulus (New Jersey) has smaller eggs (mean 97 ± 4 (SD) μm; range 91–108 μm) than S. pseudoglobulus n.sp. from Quebec (mean 116 ± 5 μm: range 103–125 μm). The cirrus in S. pseudoglobulus has a basal bulb not found in that of S. globulus. There are fewer uterine coils anterior to the acetabulum in S. pseudoglobulus. Comparison of 6-day-old populations of each species revealed several statistically significant differences in the mean size of internal organs. The overall sizes of the body, ovary, and eggs and the width of the posterior testis were greater in S. pseudoglobulus: the pharynx, length of the posterior testis, and number of eggs in the uterus were greater in S. globulus. No differences were found in the size of the oral sucker, acetabulum, or anterior testis.
Seasonal changes in gut size of the wild prairie vole (Microtus ochrogaster)
Authors: Hammond Kimberly A.
Published: April 2011

The gut sizes of wild adult male prairie voles (Microtus ochrogaster) were found to fluctuate throughout the year. This fluctuation was highly variable, but the changes were mainly increases in the mass of the cecum and small intestine during the fall and early winter. The gut sizes (length and dry mass) of field animals were found to be similar to those of laboratory voles fed a high-fiber diet (> 40% cell wall) and (or) held at a low temperature (5 °C). In almost all cases, the gut sizes of wild voles were greater than those of laboratory voles maintained at 23 °C and fed low-fiber diets (< 20% cell wall). Despite considerable seasonal variation in gut size, there does not appear to be a strongly repeatable relationship between time of year and changes in gut size. However, because wild voles appear to have larger guts than laboratory voles acclimated to relatively energy-demanding conditions, I suggest that wild voles are living under a greater energy demand and (or) eating lower quality diets than was previously suggested.
Nouvelles données sur la masse du squelette chez les grands cétacés (Mammalia, Cetacea)
Authors: Robineau Daniel , Buffrénil Vivian de
Published: April 2011

The mass of dry and fat-free skeletons was measured in a small sample representing five species of large cetaceans: two balaenids, two balaenopterids, and one physeterid (the sperm whale). Expressed as a percentage of total body mass, skeletal mass in these animals varies from 3.5 to 5%. Such values are very close to those established previously for small to medium size toothed whales. This means that the dynamics of mass growth of the skeleton, as compared with that of the body as a whole, does not follow a positive allometry in cetaceans. Such a growth pattern differs markedly from the tendencies described in terrestrial mammals. Conversely, it is similar to that described in bony fishes. The distribution of loads within the skeletons reflects rather different functional patterns among the taxa examined here. The possible adaptive significance of these differences is discussed in reference to the locomotion of large cetaceans.
Comment—Function of the mite pockets of lizards: an assessment of a recent attempted test
Authors: Arnold E. N.
Published: April 2011

On the basis of examining geckoes of the genus Rhacodactylus, Bauer et al. (A. M. Bauer, A. P. Russell, and N. R. Dollahon. 1990. Can. J. Zool. 68: 1196–1201) found no support for the hypothesis that mite pockets of lizards serve to concentrate chiggers, the larvae of trombiculid mites, and limit the damage they do. However, this claim can be shown to arise from insufficient observations. Further arguments that ectoparasite concentration does not confer advantages are also shown to be unsubstantiated.
Relationship of swim-bladder shape to the directionality pattern of underwater sound in the oyster toadfish
Authors: Barimo John F , Fine Michael L
Published: April 2011

The swim bladder of the oyster toadfish, Opsanus tau, has a distinctive heart shape with two anterior protrusions separated by a midline cleft. The lateral surfaces contain intrinsic muscles that meet at the caudal midline, but the rostromedial surface is muscle-free. We hypothesize that swim-bladder design represents a compromise between opposing tendencies toward (i) an omnidirectional sound source that would optimize a male's opportunity to attract females from any direction, and (ii) a directional sound source that would shield the nearby ears during sound production. To determine if the directionality of toadfish sound is consistent with this hypothesis, boatwhistle advertisement calls of individually identified males were recorded in the York River, Virginia, by means of two calibrated hydrophones and a waterproof recording system: one hydrophone was fixed 1 m in front of the fish and the second was roving. Boatwhistles in the horizontal plane propagated in a modified omnidirectional pattern that was bilaterally symmetrical. The mean sound pressure was 126 dB re: 1 µPa at 0°. The sound pressure level decreased by approximately 1 dB at ±45°, after which levels increased to 180°, averaging 3-6 dB greater behind (mean 130 dB) than directly in front of the fish. This pattern is consistent with the hypothesis that sound energy is reduced at the fish's ears. The source level and fundamental frequency of the boatwhistle were highly stereotyped, with coefficients of variation averaging less than 1%, and duration was more variable, with a coefficient of variation of 8%. Grunt levels overlapped but were slightly lower than boatwhistle values.
Extra-mammalian larval stages ofElaphostrongylus alces(Nematoda: Protostrongylidae), a parasite of moose (Alces alces) in Fennoscandia
Authors: Lankester Murray W , Olsson Ing-Marie C , Stéen Margareta , Gajadhar Alvin A
Published: April 2011

Dimensions and illustrations of the first-, second-, and third-stage larvae of Elaphostrongylus alces are presented for the first time. First-stage larvae were 417 ± 16 µm long (mean ± SD) (range 377-445 µm) and similar in size to those of E. cervi (420 ± 13 µm long; range 392-445 µm) and E. rangiferi, the other recognized members of the genus. The mean length of third-stage E. alces larvae (714 ± 23 µm long; range 675-756 µm) recovered from gastropod intermediate hosts was significantly less than that of E. cervi (831 ± 78 µm long; range 669-954 µm) and E. rangiferi, providing further evidence of the distinct status of E. alces, a recently described species from moose in Fennoscandia.
Recaching of Jeffrey pine (Pinus jeffreyi) seeds by yellow pine chipmunks (Tamias amoenus): potential effects on plant reproductive success
Authors: Wall Stephen B.Vander , Joyner Jamie W
Published: April 2011

Animals that scatter-hoard seeds frequently dig up and recache them at new locations. The effect of the recaching of seeds on plant reproductive success was studied in the Sierra Nevada of western Nevada. The fate of 1000 individually marked Jeffrey pine (Pinus jeffreyi) seeds initially placed in 100 primary caches in a 10 x 10 array was monitored during autumn 1995 and spring 1996. Yellow pine chipmunks (Tamias amoenus) quickly removed nearly all of the seeds and recached many of them in 377 secondary caches containing 727 seeds. Later, rodents dug up most of these caches and transferred them to 213 tertiary caches (283 seeds), 75 quaternary caches (92 seeds), and 13 quintic (fifth order) caches (13 seeds). Overall, rodents ate 15.3% of the seeds they took from primary through quintic caches, and an additional 71.1% of the seeds disappeared, probably to underground runways and larders. During our spring survey of the study site, 133 seeds (13.6%) from 84 caches had germinated or were about to germinate. As rodents moved seeds from cache site to cache site, several changes occurred that potentially influenced the distribution and survival of Jeffrey pine seedlings. First, the number of seeds per cache decreased. Second, cached seeds were gradually moved farther from the source area. Third, the dispersal distance between successive cache sites decreased. Fourth, the distribution of cached seeds became more even. Lastly, more seeds were cached beneath shrubs, which serve as nurse plants for Jeffrey pine seedlings. Consequently, the movement of seeds between cache sites by chipmunks may increase the probability that Jeffrey pine seedlings will establish from rodent caches.
Genital morphology of Nephila edulis: implications for sperm competition in spiders
Authors: Uhl Gabriele , Vollrath Fritz
Published: April 2011

The genital morphology of the female is assumed to control the pattern of sperm priority. Spiders are divided roughly along phylogenetic lines into haplogyne and entelegyne types, the principal difference being in female genital morphology (cul-de-sac and conduit types of spermathecae). Nephila edulis is an entelegyne spider and we studied the genital morphology of both sexes by means of scanning electron microscopy and semithin sectioning. In the female, the copulatory ducts leading to the spermatheca were much longer and more differentiated than the fertilization duct. We question the common assumption that possession of genitalia of the conduit type with separate copulatory and fertilization ducts will automatically lead to first-male sperm priority because in our typical entelegyne species, the copulatory ducts were similar in arrangement to the combined copulatory/fertilization ducts in genitalia of the typical cul-de-sac type.
Effects of woody debris on the growth and behaviour of brown trout in experimental stream channels
Authors: Sundbaum Karl , Näslund Ingemar
Published: April 2011

We examined the effects of woody debris on the growth and behaviour of brown trout (Salmo trutta) in experimental stream channels. Two types of habitat were used in the study: a complex habitat created by placing woody debris on a gravel bed and a uniform habitat consisting of a gravel bed only. The experiment was run both outdoors with wild fish that fed on natural invertebrate drift and indoors with hatchery fish that were fed artificial food. In both treatments most of the fish lost mass. In all trials, however, the fish in the woody debris channel lost less mass than the fish in the control channel. Study of the fishes' behaviour revealed less swimming activity, less aggression, and less feeding activity in the woody debris channel than in the control channel. The results of this study indicate that the presence of woody debris decreases intraspecific competition through visual isolation, allowing fish to reduce aggressive interactions and energy expenditure.
Reproduction of the earthworm Lumbricus terrestris Linné after the first mating
Authors: Butt Kevin R , Nuutinen Visa
Published: April 2011

Mature virgin individuals of the simultaneously hermaphroditic earthworm Lumbricus terrestris Linné were housed in small groups and allowed access to each other under continuous video observation. After copulation, earthworms were isolated and thereafter their mass and the number of cocoons they produced were recorded monthly. Mated individuals produced cocoons for up to 12 months after the mating, while unmated individuals produced no cocoons. Hatchability of cocoons ranged from 76 to 62% over the 5 months following the mating, but decreased to 11% in the sixth month. Cocoons produced beyond that period failed to hatch. The median period of viable cocoon production was 3 months. Monthly cocoon production peaked 2-3 months after the mating, when 2-3 (1-2 viable) cocoons per individual were produced. Median total production of viable cocoons was 5 per individual (range 0-21). There was no discernible relationship between cocoon production and length of copulation, individual longevity, or individual mass at mating. Both partners usually contributed to the production of viable cocoons, but within mating pairs there was a median difference of 4 cocoons. Median survival time after the experimental mating period was 9 and 11 months for mated and unmated earthworms, respectively.
Beta2-adrenoceptors mediate melanosome dispersion in winter flounder (Pleuronectes americanus))
Authors: Mayo D J , Burton D
Published: April 2011

Although the melanosome-aggregating mediation of catecholamines through alpha -adrenoceptors is well established for teleost melanophores, the regulation of the dispersive process is not as clearly understood. The melanosome-aggregating effect of high concentrations of catecholamines in vitro is reversed at low concentrations with melanophores of the winter flounder, Pleuronectes americanus. In vitro incubation in low concentrations of isoproterenol ( <<= 10-7M) and noradrenaline ( <<= 10-8M) enhances Na+-induced melanosome dispersion in balanced salt solution, which can be depressed by propranolol (10-4M), indicating beta -adrenoceptor mediation in pigment dispersion. The subtype of this adrenoceptor appears to be the beta2conformation, since the beta2-adrenoceptor agonist terbutaline (>=>3.15 times 10-6M) reverses the melanosome-aggregating effect associated with higher concentrations of noradrenaline and with electrical stimulation. It is concluded that in this species there is adrenergic neuronal control of melanosome aggregation through alpha -adrenoceptors on release of noradrenaline and of dispersion through beta2-adrenoceptors during a subsequent decrease in concentration.
Genetic variation in North American black flies in the subgenus Psilopelmia (Simulium: Diptera: Simuliidae)
Authors: Tang Jianming , Moulton John K , Pruess Kenneth , Cupp Eddie W , Unnasch Thomas R
Published: April 2011

Resolution of the genetic heterogeneity of closely related insect species depends on the selection of reliable genetic markers derived from representative specimens. We report the results of a survey of genetic variability in nine species of black flies in the subgenusPsilopelmia Enderlein. Three regions of the mitochondrial genome and an amplicon including the internal transcribed spacer 1 of the nuclear ribosomal RNA gene cluster (ITS1) were amplified using the polymerase chain reaction (PCR), and the amplicons were examined for intraspecific and interspecific polymorphisms. Six of the seven Psilopelmia species that yielded PCR products in the ITS1 PCR reaction were found to generate products that were indistinguishable on the basis of size. Similarly, little interspecific variation was noted in the 16S rRNA amplicon among nine species of Psilopelmia assayed by heteroduplex analysis. In contrast, the remaining regions of the mitochondrial genome exhibited both intra- and inter-specific variation when analyzed by heteroduplex analysis. Information collected from the five amplicons could be employed to develop a classification scheme capable of distinguishing the nine species of Psilopelmia examined.
Feeding behavior of black fly larvae and retention of fine particulate organic matter in a high-gradient blackwater stream
Authors: Miller M C , Kurzhals M , Hershey A E , Merritt R W
Published: April 2011

We studied the feeding behavior of black fly larvae and aspects of fine particulate organic matter (FPOM) retention in four riffles in a high-gradient blackwater stream in northeastern Minnesota, U.S.A., using fluorescent particulate dyes as tracers of FPOM. Radiant Red and Radiant Deep Green dye particles were added sequentially to the stream above the upper riffle during two sequential 10-min pulses separated by a 5-min interval with no dye addition. Gut analyses showed that green particles were ingested progressively more at downstream riffles well after the dye pulse had passed, but red particles showed the opposite pattern. Samples of Cladophora sp. collected at the same intervals showed that green dye particles were preferentially retained over red ones by filamentous algae, and thus would have been more available than red particles to larvae functioning as collector-gatherers. Our work strongly suggests that collector-gatherer behavior, in addition to collector-filterer behavior, is important for obtaining very fine particles by larval black flies. Our work also shows that although fluorescent dye particles are useful tracers of very fine particulate organic matter for feeding studies, the two similar-sized but different-colored particles used in this study behaved differently in terms of retention on Cladophora sp. By analogy, other similar-sized FPOM, which would be more heterogeneous chemically and physically than the dye particles, might also be expected to exhibit diverse behavior, affecting its availability to consumers.
Order of oviposition and egg size in the red-eared slider turtle (Trachemys scripta elegans)
Authors: Tucker John K , Janzen Fredric J
Published: April 2011

We studied intraclutch variation in egg size and shape among 432 eggs from 35 clutches of the red-eared slider turtle (Trachemys scripta elegans) from west-central Illinois. Egg shape varied systematically with respect to oviposition order. The first two and last two eggs laid were slightly but significantly longer than eggs laid between the first two and last two eggs. The last two eggs laid were slightly but significantly narrower than other eggs in a clutch. In contrast, egg mass did not vary systematically with oviposition order. Mean egg mass of the first two eggs laid was slightly but insignificantly greater than that of the last two eggs laid and that of eggs laid between the first two and last two eggs. In this species, follicles are apparently fairly uniform in mass when they are ovulated. Consequently, reproductive output can be adjusted by either ovulating more equal-sized follicles or adding material uniformly to all follicles ovulated in a particular reproductive bout. We suggest an adaptive explanation of differences between intraclutch variation in T. s. elegans and that reported in previous studies of intraclutch variation in sea turtles.
Differential postspawning mortality among male and female capelin (Mallotus villosus Müller) in captivity
Authors: Burton Margaret PM , Flynn Shawn R
Published: April 2011

Male and female capelin (Mallotus villosus Müller) were captured in 1993 at the start of spawning and males were captured in 1995 at the end of the spawning period. All male fish from both years died within 6 weeks of capture. Spent males captured in the wild showed almost empty testes with very few residual sperm and no evidence of developing spermatocytes. All female fish survived the first 6 weeks and over 50% survived 20 weeks. Sampling of the surviving females after 20 weeks showed evidence of prior spawning and progressive development of oocytes for the next summer's spawning season. It was concluded that while males may be semelparous, females are inherently iteroparous.
Development of migratory behavior in northern white- tailed deer
Authors: Nelson Michael E
Published: April 2011

I examined the development of migratory behavior in northern white-tailed deer (Odocoileus virginianus) from 1975 to 1996 by radio-tracking adult females and their fawns. Of 40 migratory fawns with radio-collared mothers, all returned from winter ranges to their mothers' summer ranges, as did 36 fawns with unknown mothers. Of 1.5- to 3.0-year-old daughters with radio-collared mothers, 67-80% continued migrating with mothers to their traditional summer ranges. Eighty-four percent (16/19) of yearling dispersers continued migratory behavior after replacing their natal summer ranges with their dispersal ranges, and 88% (14/16) of these continued migrating to their natal winter ranges, some through at least 6.5 years of age. Twenty percent (4/20) of nonmigratory fawns dispersed as yearlings, and two became migratory between their dispersal summer ranges and new winter ranges, one through 4.9 years of age and another through 6.5 years. Seven fawns changed their movement behavior from migratory to nonmigratory or vice versa as yearlings or when older, indicating that migratory behavior is not under rigid genetic control. Thus, the adaptiveness of migration must depend upon natural selection operating upon varying capacities and propensities to learn and mimic long-distance movements and not upon migratory behavior directly.
A finite time horizon influences sequential mate choice in male Gammarus aequicauda (Amphipoda)
Authors: Thomas F , Liautard C , Cézilly F , Renaud F
Published: April 2011

Although size-assortative pairing has been extensively studied in amphipods, the influence of time left to moult (TLM) on pairing decisions of male gammarids remains largely unexplored. Given that moulting males cannot guard their mates, we investigated the influence of TLM for males on size-assortative mating in the gammarid Gammarus aequicauda (Crustacea, Amphipoda). There was a significant relationship between TLM and size in males. Unpaired males were closer to their moult than paired ones. Among pairs, there was a significant positive relationship between male and female sizes and between male and female TLM values. However, males closer to the moult were paired with females of more varying sizes than were other males, suggesting that a decrease in TLM reduces choosiness in males. Although there was a significant relationship between TLM and size in males, size-assortative mating was independent of male TLM.
Spruce budworm outbreaks and the incidence of vagrancy in eastern North American wood-warblers
Authors: Patten Michael A , Burger Jutta C
Published: April 2011

The Tennessee (Vermivora peregrina), Cape May (Dendroica tigrina), Bay-breasted (D. castanea), and Canada (Wilsonia canadensis) warblers and the Ovenbird (Seiurus aurocapillus) appear to show positive numerical responses to outbreaks of the spruce budworm (Choristoneura fumiferana); the Magnolia (D. magnolia), Black-throated Green (D. virens), and Blackburnian (D. fusca) warblers may occur in lower numbers during outbreaks because of increased competition with these budworm specialists. Thus, we predicted that the number of fall vagrant Tennessee, Cape May, and Bay-breasted warblers and Ovenbirds occurring in California are highly positively associated with budworm population density, positively intercorrelated, and negatively associated with numbers of Magnolia, Black-throated Green, and Blackburnian warblers. A 23-year (1972-1994) data set of budworm population densities and vagrant warbler occurrences in California showed that (i) budworm population density was an excellent predictor (explaining about 50% of the variance) of numbers of occurrences of the Cape May, Bay-breasted, and Canada warblers; (ii) all warbler species tended to co-occur, with numbers of Cape May and Bay-breasted warblers especially highly intercorrelated; and (iii) Magnolia Warbler numbers were negatively associated with those of budworm specialists, but Black-throated Green and Blackburnian warblers showed no association.
Sterile intersexuality in an isopod induced by the interaction between a bacterium (Wolbachia) and the environment
Authors: Rigaud T , Juchault P
Published: April 2011

An endocellular bacterium of the genus Wolbachia changes chromosomic (ZZ) males into functional females in a number of populations of the woodlouse Armadillidium vulgare. The interaction between the feminizing effect of Wolbachia and the lethal effect of high temperature on these bacteria is shown to be responsible for the appearance of high proportions of sterile intersexes (Si). Wolbachia-infected females produced an average of 15% Si when reared for 200 days under a daily thermoperiodic regime that included 4 h at 30°C. A temperature of 30°C is known to destroy Wolbachia. The Si phenotype may therefore be due to the partial destruction (or inhibition) of the feminizing bacteria by high temperature during development. This induction of a proportion of Si differs in two ways from the intersexuality induced by the conflict between the feminizing agent and a host autosomal gene. First, the genomic conflict does not lead to the production of numerous Si, and second, the temperature-dependent production of Si is a sporadic event induced by the environment, rather than being a heritable trait. The overproduction of sterile offspring at high temperatures can result inWolbachia-infected females of A. vulgare suffering a loss of fitness.
Reproductive strategies of Dicrostonyx groenlandicus and Lemmus sibiricus in high-arctic tundra
Authors: Negus Norman C , Berger Patricia J
Published: April 2011

From 1981 to 1984, a field study of reproductive strategies of Lemmus sibiricus and Dicrostonyx groenlandicus in high-arctic tundra was undertaken at Igloolik Island and the Melville Peninsula, Northwest Territories. Both species of lemmings were scarce in 1981 and 1982 and increased rapidly in abundance in 1983 and 1984. In 1983, D. groenlandicus began breeding in March under the snow, whereas L. sibiricus did not commence breeding until meltoff in early June. Breeding in L. sibiricus was coincident with the appearance of the first sprouts of Dupontia fisheri and Carex stans, two of its preferred monocotyledonous food plants. A survey of tundra plants revealed that 6-methoxybenzoxlazolinone (6-MBOA) was present in the monocotyledons that are the preferred food plants of L. sibiricus, but not in those that are not preferred. With one exception, stoloniferous species contained 6-MBOA but caespitose species did not. Dupontia fisheri showed considerable yearly variation in 6-MBOA content, consistent with low and high population years for L. sibiricus. None of the dicotyledons preferred by D. groenlandicus contained 6-MBOA. Laboratory assays demonstrated that L. sibiricus responds reproductively (increased uterine mass) to 6-MBOA, but D. groenlandicus does not. We conclude that D. groenlandicus uses photoperiod to cue its reproductive effort, while plant chemical cues are an important component of the reproductive strategy of L. sibiricus.
The use of exposed diurnal roosts in Alberta by the little brown bat, Myotis lucifugus
Authors: Riskin Daniel K , Pybus Margo J
Published: April 2011

The use of exposed diurnal roosts by the little brown bat,Myotis lucifugus, throughout the summer months is only known to occur among Alberta populations of this species. This study is the first to examine that behaviour. In total, 426 M. lucifugus using exposed anthropogenic surfaces as diurnal roosts were observed in the summers of 1985 and 1986. Bats were usually found alone, but groups of up to six individuals were seen. When found at these roosts, 98.8% of bats were at least 2 m from the ground and 95.1% were below an overhang. Bats were found on brick substrates in 89.0% of observations and in the corner between two surfaces in 57.0%. Bats were found on east-facing surfaces less frequently than expected under random distribution. Roost selection appears to have been based on several strategies, including thermoregulation, predator avoidance, and desiccation avoidance. After maternity roosts were vacated, the proportion of juveniles at exposed roosts was higher than their proportion in the total population. This may be the result of their inability to enter, or lack of knowledge of, many enclosed roosts used by adults.
A morphological and genetic comparison ofPatrobus fossifrons(Eschscholtz) andPatrobusstygicusChaudoir (Coleoptera: Carabidae)
Authors: Pohl Gregory R
Published: April 2011

Specimens of Patrobus fossifrons (Eschscholtz) and Patrobus stygicus Chaudoir were examined for morphological and enzymatic characteristics. Differences in both character types were found between the species. Differences were also found among populations of P. fossifrons; a "coastal" morph and an "inland" morph are described and their biogeographical history is traced to glacial refugia. Patrobus stygicus populations were homogeneous for all characters studied. Patrobus stygicus and inland P. fossifrons co-occurred at Cypress Hills and in the Pincher Creek area in Alberta. No evidence of hybridization was found at Cypress Hills. At Pincher Creek, 2 out of 299 beetles examined were hybrids, but there was little evidence that this rate of hybridization had resulted in any gene flow between the species. Patrobus stygicus and coastal P. fossifrons co-exist and hybridize in central Washington State. Electrophoretic analysis of a mixed-stock specimen proved that at least some hybrids are fertile. However, a combination of hybrid disadvantage and low hybridization rates keeps gene-flow levels very low. It is concluded that despite a small amount of hybridization, P. stygicus and P. fossifrons remain separate species.
Parent-offspring discrimination in the prairie vole and the effects of odors and diet
Authors: Phillips Michael L , Tang-Martinez Zuleyma
Published: April 2011

The objectives of this study on the prairie vole (Microtus ochrogaster) were to determine whether (i) parents are able to distinguish their own young from alien young, (ii) conspecific odors influence parent-offspring discrimination, and (iii) diet affects the cues used in parent-offspring discrimination. Parent-offspring discrimination was inferred from differential behaviors directed by adults towards their own offspring and alien offspring. In experiment 1, parent-offspring dyads showed high frequencies of cohesive behaviors and low frequencies of agonistic behaviors, while dyads of adults and alien offspring showed significantly more agonistic and fewer cohesive behaviors. In experiment 2, dyads of parents with their own offspring were tested in an arena containing their own soiled shavings, soiled shavings from another family, or clean shavings. Dyads engaged in significantly fewer investigatory behaviors and more cohesive behaviors when tested with their own familiar odors than when tested with unfamiliar odors or odors from clean shavings. In experiment 3, we tested dyads of unrelated adults and young that had been fed either the same or different dietary supplements. There were no significant differences in the frequencies of investigatory, cohesive, or agonistic behaviors in dyads fed the same diet and those fed a different diet.
Over-winter survival of first-stage larvae ofParelaphostrongylus tenuis (Nematoda: Protostrongylidae)
Authors: Forrester Sean G , Lankester Murray W
Published: April 2011

This study examined the ability of first-stageParelaphostrongylus tenuis larvae to survive winter conditions at the northern limits of the white-tailed deer (Odocoileus virginianus) range. Fecal pellets freshly deposited by infected deer were collected at the beginning of each winter month (9 December 1996 to 12 March 1997) and placed out in a traditional deer wintering area located near Grand Marais, Minnesota, and at a site in Thunder Bay, Ontario. The temperatures experienced by larvae at different levels within the snow cover were monitored and survivorship was calculated each month. Overall larval survivorship from December to April was only 27%. Although temperatures experienced by larvae beneath the snow for 4 months at Grand Marais were greatly moderated (-0.2 to -2.5°C) compared with air temperatures (6.5 to -24.0°C), fewer larvae survived (16%) than at a lower, constant temperature (-14oC) in the laboratory (76%). The mean numbers of first-stage larvae passed by deer (expressed per gramof dried feces (gd)) varied considerably over winter, from a low of 289/gd in December to a peak of 1127/gd in March. Considerable reproductive potential was lost because this spring (March) rise occurred before the end of winter. Nonetheless, the meningeal worm still successfully infects up to 82% of white-tailed deer in northern areas, and it is probably those larvae produced during the snow-free period while deer are dispersed over their summer habitat that play the biggest role in transmission.
Factors contributing to the maintenance of the genetic polymorphism at the locus LDH-B in the pool frog,Rana lessonae
Authors: Schmidt Benedikt R , Hotz Hansjürg , Anholt Bradley R , Guex Gaston-Denis , Semlitsch Raymond D
Published: April 2011

We tested for environmental factors that may lead to balancing selection and to the maintenance of a genetic polymorphism at the enzyme locus lactate dehydrogenase B (LDH-B) in the pool frog, Rana lessonae. We raised tadpoles individually in a factorial experiment in which we manipulated temperature, food level, and food quality. The only statistically significant difference among LDH-B genotypes was in growth rate, with the heterozygote performing best. Although the difference was not significant, heterozygotes also tended to perform best for size at metamorphosis. However, heterozygotes did not perform best in terms of other traits (age at metamorphosis and rates of survival and metamorphosis), where differences among LDH-B genotypes were also not significant. The size of the effect of LDH-B genotype depended on the environment, which suggests that the locus may be selectively neutral in some environments. There were no genotype-environment interactions in the sense that reaction norms along environmental gradients did not cross. When we raised tadpoles in groups, e/e homozygotes had a significantly higher body mass and developed at the significantly highest rate. In addition, there may be a trade-off between larval and adult performance: adult frogs show a different ranking in performance of LDH-B genotypes than tadpoles do. These results suggest that this genetic polymorphism is maintained through heterozygote advantage, possibly in conjunction with antagonistic pleiotropy.
Distribution, prevalence, and pathogenicity of the protozoan Perkinsus qugwadi in Japanese scallops, Patinopecten yessoensis, cultured in British Columbia, Canada
Authors: Bower Susan M , Blackbourn Janice , Meyer Gary R
Published: April 2011

Perkinsus qugwadi was detected in cultured Japanese scallops, Patinopecten yessoensis, held for at least 3 months at 5 of 14 locations along the coast of British Columbia. At four of the locations, infected scallops were observed in over half of the samples examined and the prevalence of infection reached 98%. At one location (Cypress Bay), infected scallops were rarely encountered and when infection was present, the intensity was light. Field studies, laboratory experiments, and commercial grow-out operations indicate that high mortalities among Japanese scallops are associated with P. qugwadi infection. Although some scallops responded to infection with an accumulation of numerous haemocytes in the vicinity of the parasite, other scallops appeared not to respond and were overwhelmed by numerous parasites that multiplied in the connective tissues of all organs. Epizootiology of this pathogen in Japanese scallops suggests that P. qugwadi is enzootic in an unknown host in British Columbia, with the introduced Japanese scallop serving as an aberrant host.