bluuebunny/crossref_metadata_2025 huggingface dataset:
The control of production of a sexual pheromone in the female guppy, Poecilia reticulata
Authors: Meyer J. H. , Liley N. R.
Published: August 2008

A pheromone produced by the female guppy, Poecilia reticulata, serves as a sexual attractant and stimulant to conspecific males. Addition of water from a container holding intact gravid "test" females caused an increase in male courtship directed towards ovariectomized "stimulus" females. There was no increase in courtship of males exposed to water from ovariectomized "test" females, and the response was not restored by treating the ovariectomized "test" females with estrogen. Pheromone production is prevented by hypophysectomy but is restored in hypophysectomized females by treatment with salmon gonadotropin or estrogen. These results indicate that pheromone is produced in the ovary itself under the control of ovarian hormone. Trials in which ovarian extracts or estrogen were added as test solutions failed to confirm earlier suggestions that the pheromone is present in ovarian tissue or that it is in fact an estrogen.
The development of the stratum granulosum of the small intestine of the rainbow trout (Salmo gairdneri)
Authors: Bergeron T. , Woodward Bill
Published: August 2008

The ontogeny of the stratum granulosum within the small intestine of the rainbow trout (Salmo gairdneri) was related to the chronological age of the animal. The component granule cells were first seen many weeks after the development of the collagenous stratum compactum. It is therefore concluded that the granule cells do not perform a critical role in stratum compactum formation. In addition, it is proposed that the stratum granulosum develops because of resistance of the stratum compactum to cellular penetration.
Relationships of amphiberingian shrews of the Sorex cinereus group
Authors: Jong C. G. van Zyll de
Published: August 2008

Nine taxa of shrews of the Sorex cinereus group occurring in northwestern North America and northeastern Siberia were studied to elucidate their interrelationships. Canonical variate analysis, cluster analysis (unweighted pair group method analysis), and numerical cladistic analysis of craniometric and external characters demonstrate the existence of four distinct forms: (1) Nearctic woodland forms, represented by Sorex c. cinereus, S. c. hollisteri, and S. c. streatori, (2) Holarctic tundra forms, represented by S. c. ugyunak and S. c. portenkoi from the North American and Asian mainland, respectively, and by S. jacksoni and S. c. leucogaster, two insular forms from St. Lawrence Island and Paramushir; (3) S. c. camtschatica, a Siberian woodland form; (4) S. pribilofensis from St. Paul Island.Of these forms, the last three are closer to one another and probably evolved in Beringia, whereas the Nearctic woodland forms probably evolved south of the Laurentide and Cordilleran ice sheets and dispersed into the Beringian area only since deglaciation.
Ultrastructure of intraocular muscles of diving and nondiving ducks
Authors: Sivak J. G. , Vrablic O. E.
Published: August 2008

The fine structure of ciliary muscle (CM), iris sphincter (IS), and neuromuscular junctions (NMJ) were studied by light and transmission electron microscopy in domestic ducks (Anas platyrhynchos) and diving ducks (Mergus merganser). Previous work has shown that the iris produces exaggerated acommodative ability in the diver. Both muscles are striated in the two species. While both muscles of domestic ducks and the CM of the diving ducks consist of one cell type, the IS of the latter is made up of two types of cells referred to as "light" and "dark." The "light" cell has long, thin, uniformly distributed mitochondria, while in the "dark" cells they are large, unevenly dispersed and often aggregated subsarcolemmally. The sarcoplasmic reticulum is more abundant in both IS and CM of domestic ducks, while well developed T tubules are seen more regularly in the intraocular muscles of diving ducks.The NMJ's do not show the complexity seen in singly innervated skeletal muscle fibres. All the nerve axon terminals end in a flat shallow trough and postjunctional folds are either nonexistent or very shallow. The NMJ's of the IS of domestic ducks and of the "dark" cell of the IS of diving ducks consist of a large single end plate. That of the CM of domestic ducks consists of a diffuse single end plate while the NMJ of the CM of diving ducks consists of diffuse multiple endings. Nerve endings of similar size and structure but occurring only singly were found on the "light" cell of the IS of domestic ducks.
Resource partitioning between brook trout (Salvelinus fontinalis Mitchill) and creek chub (Semotilus atromaculatus Mitchill) in selected oligotrophic lakes of southern Quebec
Authors: Magnan Pierre , FitzGerald Gérard J.
Published: August 2008

The spatial distribution, food habits, and growth of an allopatric brook trout (Salvelinus fontinalis) population was compared with a trout population coexisting with creek chub (Semotilus atromaculatus). Sympatric trout differed in spatial distribution and food habits from allopatric trout suggesting a niche shift of the trout when they live with creek chub. Also, although there is a certain overlap in diet and spatial distribution, sympatric populations of the two species differed on these resource axes. However, growth of sympatric trout is not clearly related to the presence or absence of the creek chub, suggesting that factors other than interspecific competiton may affect growth in the seven study lakes.
Composition, structure, and competitive behaviour in a guild of Ecuadorian rain forest dung beetles (Coleoptera; Scarabaeidae)
Authors: Peck Stewart B. , Forsyth Adrian
Published: August 2008

A guild of neotropical rain forest dung scarabs, collected by baited pit traps, was composed of 11 genera and 31 species of Scarabaeinae. Relative abundances were highly equitable. Population densities were high and stable through the transition from wet to dry season. Competition for dung was intense and removal and burial rates were rapid. Resource use differed between genera and species in diel flight activity, foraging and dung removal methods, and behavior. Interspecific aggression and dung stealing behaviors were well developed. Reproductive activity was inversely correlated with aggression and parental investment.
The cuticular vestiture of larvae of Aedes communis and A. nevadensis (Diptera:Culicidae)
Authors: Belton Peter
Published: August 2008

The first confirmed larvae of Aedes nevadensis from Canada were taken in southeastern British Columbia in 1981. They were compared with those of A. communis sensu stricto, also from British Columbia. The scales of the comb differed markedly, and the teeth of the pecten differed slightly. The form and arrangement of vesicles on the head capsule and the microspines on the prothorax appeared to be identical in these two members of the A. communis group. Aedes nevadensis may have been misidentified as A. communis over much of its currently known range.
Giardia lamblia: axenic growth in autoclaved and filtered Diamond's TYI-S-33 medium
Authors: Belosevic M. , Faubert G. M. , Croll N. A. , MacLean J. D.
Published: August 2008

The trophozoites of Giardia lamblia were gradually adapted to grow in both autoclaved and filtered Diamond's TYI-S-33 culture medium. Comparative growth studies indicated that the growth of organisms was significantly higher in filtered TYI-S-33 medium. In both types of media the exponential growth phase occurred between 48 and 96 h postinoculation. The mean number of trophozoites at 96 h was 1.94 × 105 and 4.82 × 105 cells/mL for autoclaved and filtered media, respectively. The generation times for the exponential growth phase were 9.66 h. for autoclaved and 7.69 h for filtered medium. The percentage of dead trophozoites was similar in both media and was 14% for the first 8 days postinoculation.
The effects of independent sodium and chloride depletion on ion balance in freshwater mussels
Authors: Scheide John I. , Dietz Thomas H.
Published: August 2008

Ligumia subrostrata maintained in choline chloride or Na2SO4 exhibited a loss of either sodium or chloride from the blood at rates similar to those observed in mussels kept in deionized water. When the ion-depleted mussels were returned to a medium containing the depleted ion, the influx of the depleted ion was increased while the efflux was depressed compared with control mussels. Blood sodium concentrations, in mussels undergoing sodium depletion, decreased linearly to approximately 50% of the normal condition, while calcium levels increased. Blood chloride concentrations decreased exponentially during depletion, with the mussel capable of withstanding an 80% reduction. Blood bicarbonate levels increased in mussels undergoing chloride depletion. The elevation of the blood bicarbonate in chloride-depleted and calcium in the sodium-depleted mussels resulted in partial compensation for the sodium chloride lost from the blood, by helping maintain the total solute and the balance of ionic charge, and may act to "prime" the active ion transport processes. When returned to media containing the depleted ion, the mussels reaccumulated sodium and chloride within 2 to 4 days. These data provide evidence for the presence of independent regulatory mechanisms for sodium and chloride.
Impact of red-winged blackbirds on singing activities of long-billed marsh wrens
Authors: Picman Jaroslav
Published: August 2008

Male long-billed marsh wrens prefer to sing from the tops of cattails, but red-winged blackbirds force wrens to sing from lower perches on cattails. The response of marsh wrens to redwing aggression declines with increasing distance from redwings. Marsh wrens that are frequently exposed to redwing aggression respond less strongly to redwings at intermediate redwing–wren distances than wrens that rarely encounter redwings. This is probably because marsh wrens habituate to redwings and learn to respond only to those situations when redwings present an immediate threat.Marsh wrens responded strongly to redwings but little or not at all to nine other species that approached them. This species-specific response is most likely associated with redwing–wren aggressive interference. It is proposed that by suppressing marsh wren singing activities redwings might depress the mating success of male marsh wrens that defend territories near redwing breeding areas.
A new species of Copidognathus Trouessart (Acari: Actinedida: Halacaridae) from the Galapagos Rift
Authors: Krantz G. W.
Published: August 2008

Descriptions of the female and protonymph of Copidognathus papillatus n. sp. are presented. Specimens were collected from a mussel outcrop on the walls of a hydrothermal vent during the Galapagos Rift Biology Expedition of 1979.
The genus Anonyx (Crustacea, Amphipoda) in the North Pacific and Arctic oceans: Anonyx nugax group
Authors: Steele D. H.
Published: August 2008

Thirteen species of the Anonyx nugax group (uropod 2 partially constricted) are listed for the North Pacific and adjacent Arctic ocean. Two new species, Anonyx beringi and Anonyx barrowensis are described; A. pacificus Gurjanova, A. anivae Gurjanova, A. comecrudus Barnard, and A. epistomicus Kudrjaschov are redescribed; and the status of the other species is reconsidered and commented upon. Only four of these species, nugax, sarsi, lilljeborgi, and debruyni, have circumpolar distributions, with the other nine confined to the North Pacific region or to it and adjacent seas.
Temporal geographic variation in the lambing season of bighorn sheep
Authors: Thompson Richard W. , Turner Jack C.
Published: August 2008

Temporal geographic variation in lambing seasons was statistically assessed for 22 populations, including 5 ecological races, of North American bighorn sheep (Ovis canadensis ssp.) from the Canadian National Parks (52° N) to western Texas (30° N). Throughout their distribution, bighorn lambing occurs coincident with the period of vegetative development when the environmental regime ameliorates neonate survival. Analyses generally demonstrate later and shorter lambing seasons in higher latitudinal populations (P < 0.001). Inception of lambing occurs later with colder temperatures, increased snowfall, at higher latitudes and elevations, and with later and shorter growing seasons [Formula: see text]. Additionally, a significant (P < 0.001) divergence in the reproductive "strategy" (median onset and duration of lambing) exists between bighorn herds of the Sierra Nevada Mountains, California (37° N) and the Desert National Wildlife Range, Nevada (36° N) as a result of two distinct, but adjacent environmental regimes. Lambing in northern populations is cued to a brief, relatively predictable period of plant growth. Southern bighorn protract lambing such that some recruitment coincides with relatively unpredictable plant growth, triggered by erratic rains.
Identification and partial characterization of digestive proteinases from two species of bedbug (Hemiptera: Cimicidae)
Authors: Houseman Jon G. , Downe A. E. R.
Published: August 2008

The digestive midgut of Cimex hemipterus (Fabr.) and Cimex lectularius L. contains cathepsin B, aminopeptidase, and an acidic proteinase that hydrolyzes haemoglobin at an optimal pH of 3.4. Cathepsin B was demonstrated by hydrolysis of benzoyl-DL-arginine-β-napthylamine at an optimal pH of 5.4. Hydrolysis of the substrate was activated by thiol chemicals and EDTA and inhibited by iodoacetamide (IAA) and horse serum. Maximum aminopeptidasehydrolysis of leucine-p-nitroanilide occurred at pH 8.4. Aminopeptidase activity was activated by MgCl2 and inhibited by EDTA, thiol chemicals, and CaCl2. Only C. hemipterus aminopeptidase was inhibited by IAA. The digestive proteinases in bedbugs are similar to those reported for other blood-sucking hemipteran insects.
Seasonal changes in the plasma levels of glycoprotein antifreeze, Na+, Cl−, and glucose in Newfoundland Atlantic cod (Gadus morhua)
Authors: Fletcher G. L. , Slaughter D. , Hew C. L.
Published: August 2008

A seasonal study was carried out on the hematocrits, plasma freezing point depression, and thermal hysteresis, and plasma Na+, Cl−, total protein, and glucose concentrations in laboratory maintained Atlantic cod. Significant thermal hysteresis was evident in the plasma during the months of January to May indicating the presence of antifreeze glycoproteins. Plasma freezing point depression and Na+ and Cl− concentrations were highest during the winter months and lowest during the summer. Two peaks in glucose levels were evident; one in February and the other in July. No seasonal changes were evident in hematocrits and total plasma protein concentrations.
Cryopreservation of zebra fish spermatozoa using methanol
Authors: Harvey Brian , Kelley R. Norman , Ashwood-Smith M. J.
Published: August 2008

We describe a method for cryopreservation of milt from individual Brachydanio rerio using methanol and powdered milk as cryoprotectants. Motility was positively correlated with hatching, which averaged 51 ± 35.6% in a typical experiment. Variablity in motility and hatching was not correlated with sperm volume or age of the fish, and is believed to be due to differences in sperm quality between individuals, as well as technical constraints imposed by the short duration of motility in thawed spermatozoa.
An analysis of locomotor body movements in pronghorn antelope
Authors: Bullock Robert E.
Published: August 2008

Slow-motion film sequences of pronghorn antelope were analyzed to determine movements of the body and various body members during the most frequently employed gaits: walk, trot, canter (lope), and gallop. As speed and gait progress from a walk to a gallop, the angles at which the legs strike and leave the ground become more acute, the body is lower to the ground, and each leg moves through a greater arc during ground contact. Inasmuch as the body levels out somewhat, it is suggested that less energy may be required in raising the center of gravity. This may make more energy available for moving the legs. As speed increases, the feet are lifted progressively higher, the legs travel further, and the feet attain greater backward acceleration before striking the ground. In the gallop, the forelegs are kept fully extended until contacting the ground and the degree of spinal flexure is increased, thus extending stride length to its maximum. Vertical movement of the head increases in the faster gaits and appears to play a larger role in shifting the center of gravity, increasing speed, and maintaining equilibrium.
Quantitative relationship between ingested blood and follicular growth in the stable fly, Stomoxys calcitrant
Authors: Chia Loo Sar , Baxter James A. , Morrison Paul E.
Published: August 2008

Female stable flies, Stomoxys calcitrans (L.), fed blood at 24-h intervals, required five blood meals to produce their first batch of eggs. The first three blood meals mainly promoted growth of the adult fat body but the latter two meals resulted in rapid ovarian growth accompanied by a decline in fat body weight. Thus, the lack of gonotrophic concordance in these flies can probably be attributed to a shortage of reserves carried over from the larval stage. Ovariectomy at emergence resulted in hypertrophy of the adult fat body in blood-fed females, indicating that the ovary regulates the flow of nutrients from the fat body during vitellogenesis.
Redescription of Pectinospirura argentata Wehr, 1933 (Nematoda: Acuarioidea) from Larus delawarensis Ord (Laridae)
Authors: Wong P. L. , Anderson R. C.
Published: August 2008

Pectinospirura argentata Wehr, 1933 is redescribed on the basis of specimens from the proventriculus of ring-billed gulls, Larus delawarensis Ord, from Lake Ontario. The specimens were compared with the paratypes of Wehr (1933). Pectinospirura sobolevi Turemuratov, 1965 is considered a synonym of P. argentata and the validity of the remaining two species P. multidentata Sobolev, 1943 and P. tringae Wang, 1976 is discussed.
Ration alimentaire et bilan énergétique individuel dans une population de montagne de Lacerta vivipara
Authors: Pilorge Thierry
Published: August 2008

The diet of Lacerta vivipara was estimated in the laboratory by determining the relationship between fecal production and food intake. Transposed to free-living individuals, this relationship between the daily consumption C in milligrams of dry weight and the total fresh weight of lizards in grams becomes C = 20.4 W0,85. By knowing the number of days during which lizards can eat, the assimilation rate, the weight increase, the mean weight of the tail, the rate of autotomy, and the weight of a brood, the individual energy budget has been established for each sex according to age. The proportion of the assimilated biomass used for growth reaches a peak in young lizards, then decreases regularly to a negligible degree in older animals. The energy used for reproduction is low at first in primiparous females but becomes three times as great in older females.[Traduit par le journal]
A new species of Bacescuella Hrabĕ (Oligochaeta, Tubificidae) from the Pacific Coast of Canada
Authors: Baker H. R. , Erséus C.
Published: August 2008

The marine, littoral Bacescuella labeosa sp. nov. is characterized by the presence of a copulatory apparatus unique within the Tubificidae as well as an unpaired dorsal spermatheca and external spermatophores. The definition of Bacescuella Hrabĕ is amended to include species with the male terminalia modified as lips and unstalked external spermatophores.
The principle of equal opportunity: a test with desert rodents
Authors: M'Closkey Robert T.
Published: August 2008

A basic assumption of the theory of niche overlap and limiting similarity is that the use of limited resources by coexisting species is proportional to resource availability. I provide a test of this assumption with desert rodents using microhabitat structure as a resource. Utilized and available microhabitat frequencies were compared in four desert rodent species. Some rodent species departed significantly in utilized microhabitats from that expected on the basis of availability. However, cumulative utilization frequencies for all four rodent species corresponded closely to the frequency of available microhabitats. Therefore, the assumption of constant ratios of utilization/availability of resources (microhabitats) was not falsified for the entire guild, although individual rodent species used some microhabitats disproportionately.
Polygamy in the mottled sculpins (Cottus bairdi) of southwestern Montana (Pisces: Cottidae)
Authors: Brown Luther , Downhower Jerry F.
Published: August 2008

Relationships among nest sites, guardian male size, and male courtship success (number of matings per male) were examined in 11 populations of mottled sculpins (Cottus bairdi) in the Madison River in southwestern Montana during the 1978 and 1979 breeding seasons. The number of matings per breeding male ranged from 1 to 12. Sites used as nests were not a random sample of available sites but were larger than average-sized rocks on the stream bed. Larger males had larger nest sites. Male courtship success was sometimes correlated with nest size. The best predictor of male mating success was male size. These observations are consistent with the hypothesis that polygamy in mottled sculpins has evolved through female choice, not through resource defense.
Systematics and ecology of the estuarine amphipod crustacean Lepidactylus dytiscus Say, 1818 (Haustoriidae)
Authors: Grant Jonathan , Lazo-Wasem Eric A.
Published: August 2008

Based on populations from the North Inlet estuary, South Carolina, the sand-burrowing haustoriid amphipod Lepidactylus dytiscus is redescribed and figured in detail for the first time. Lepidactylus dytiscus is endemic to the southern United States Atlantic coast where it is essentially marine and largely intertidal. It characteristically occurs in lower salinities and muddier sediments than other regional haustoriid species. Adult body size and morphology show considerable variation between populations within North Inlet. A generic emendation is given and revised keys are presented to distinguish the genus Lepidactylus from Parahaustorius and Haustorius, and L. dytiscus from Gulf Coast species of Lepidactylus.
Fleas (Siphonaptera) from vole nests in subarctic Alaska
Authors: Haas Glenn E.
Published: August 2008

Vole fleas totalling 2420 specimens were obtained from 160 of 291 nests, principally of Microtus spp., collected in 66 localities in five regions of Alaska below the Arctic Circle, from 1973 to 1980. Six taxa were in family Hystrichopsyllidae, three in Leptopsyllidae, and five in Ceratophyllidae. Seven taxa are known as Nearctic and six as Amphiberingian, and together in Alaska they form a complex of distribution patterns that was examined from a pentaregional viewpoint. Nearctic forms were preponderant, in numbers of individuals if not taxa, in the southeast, south central, and southwest regions; Amphiberingian forms were preponderant in the interior and especially the west central region. Rearing records suggested that three of the taxa have more than one generation per year. A few shrew, ground squirrel, and ermine fleas were also found in vole nests, and two taxa of vole fleas were reared from lemming nests.
The naupliar instars of Diaptomus kenai (Copepoda, Calanoida) and their distinction from those of four other diaptomids
Authors: Green J. D. , Northcote T. G.
Published: August 2008

The development of the six naupliar instars of Diaptomus kenai from Loon Lake in the University of British Columbia Research Forest is described and illustrated. The nauplii of D. kenai and of four other diaptomid species from lakes in the reseach forest are distinguished using differences in caudal armature and body size.
Electrophysiological response of Dendroctonus pseudotsugae and Ips paraconfusus (Coleoptera: Scolytidae) to selected wavelength regions of the visible spectrum
Authors: Groberman L. J. , Borden J. H.
Published: August 2008

Electroretinograms (ERGs) were recorded from the compound eyes of both sexes of Dendroctonus pseudotsugae Hopkins and Ips paraconfusus (Lanier). Light stimuli between 400 and 650 nm were delivered to the compound eyes through a monochromator connected to a fiber-optics and lens light-delivery system. Stimulus intensity was regulated with neutral density filters. The averaged spectral response curves were similar for both species and sexes. The spectral sensitivity curves disclosed two sensitivity maxima, one in the blue region (450 nm) and one in the green region (510 to 530 nm). These correspond well with behavioural data on scolytids and with response peaks reported in other insects and provide evidence that the scolytid visual system consists of two receptor types. The blue receptors are probably used in navigation during the initial stages of the dispersal flight and the green receptors for the detection of spatial information during host selection.
Feeding methods and diving rates of migrating larids off Deer Island, New Brunswick
Authors: Braune B. M. , Gaskin D. E.
Published: August 2008

A study of three species of migrating larids was undertaken off Deer Island, New Brunswick, to compare feeding methods and diving rates of birds exploiting various prey types. Bonaparte's Gulls (Larus Philadelphia) fed mainly by diving (dipping and plunging) and surface seizing, whereas Common and Arctic Terns (Sterna hirundo and S. paradisaea) acquired food by diving only. Common and Arctic Terns foraged from greater heights than Bonaparte's Gulls, and both the gulls and the terns maintained a higher foraging height while feeding on small fish than while feeding on euphausiids or, in the case of the gulls, insects. Common and Arctic Terns had a steeper dive angle than Bonaparte's Gulls, and both the gulls and the terns dove more steeply when feeding on small fish than on euphausiids. The highest diving rate occurred when Bonaparte's Gulls were dipping for insects trapped in the water surface layer. There was no significant difference in mean dipping or plunging rates between the gulls and the terns feeding on euphausiids or small fish. Bonaparte's Gulls had a lower mean rate of incomplete dives than did terns, probably because of the gulls' lesser aerial manoeuverability reducing the likelihood of altering course after dive initiation. The mean dipping rate was higher than the mean plunging rate for both the gulls and the terns since most food was taken at the surface, and plunges were necessary only for deeper prey (usually small fish). Intervals between hovering and diving were similar for both the gulls and the terns.
Steroid hormones in the blood plasma of Townsend's vole (Microtus townsendii)
Authors: McDonald I. R. , Taitt M. J.
Published: August 2008

Measurements of the concentrations of total corticosterone, corticosteroid-binding globulin (CGB), and total androgen in the plasma of male and female Microtus townsendii were made on two occasions separated by 13 days during a spring decline in numbers. The females had a much higher (7- to 12-fold) total and free corticosterone concentrations in their plasma than the males. Also, with the single exception of a female with no evidence of preceding pregnancy, which had a very low plasma androgen concentration, the concentration of steroids, resembling testosterone and dihydrotestosterone, in the plasma of the females was about double that in males with capture weights less than 80 g. Males, both wild and captive, with body weights in excess of 80 g at some time had plasma androgen concentrations up to fourfold those of the smaller males. Castration of males had no effect on total corticosterone or CBG concentration of the plasma. It is suggested that, at the time of sampling, the females were more readily stressed than the males and, hence, were at risk from the deleterious effects of excessive adrenocortical activity. The males taken from the wild population probably represented displaced animals, rather than more reproductively successful resident males. The source of the high total androgen concentration in the plasma of the females could be a special zone in the adrenal cortex which is known to appear after the first pregnancy in female Microtus agrestis.
Oocyst production, late-stage merogony, gametogony, and cross-transmission studies of Eimeria bubonis (Protozoa: Eimeriidae) of the great horned owl, Bubo virginianus
Authors: Cawthorn Richard J. , Stockdale P. H. G.
Published: August 2008

The study was designed to examine oocyst production, endogenous development and host specificity of Eimeria bubonis (Protozoa: Eimeriidae). Three great horned owls were administered 1.0 × 104 sporulated oocysts of E. bubonis orally. Three more great horned owls were each fed two mice which had been previously intubated with sporulated oocysts of E. bubonis. Feces were examined daily after flotation and oocyst production was estimated. One great horned owl was administered 2.25 × 105 sporulated oocysts of E. bubonis, killed 5.5 days later and examined histologically. Domestic chicks were administered oocysts of E. bubonis and their feces examined as above. Mice were administered sporulated oocysts of E. bubonis and then killed sequentially. Tissues of chickens and mice were examined histologically. The prepatent period of E. bubonis in great horned owls was 5.0–6.0 days; the patent period was as short as 4–6 days. Maximal oocyst production occurred 6–7 days after infection. Endogenous development occurred distal to nuclei of villar epithelial cells in the anterior half of the small intestine. E. bubonis was not transmissible to chickens. Pyogranulomas developed and persisted 12 weeks in mice administered E. bubonis; however, there were no stages of E. bubonis infective to great horned owls.
The development of the central nervous system in Capitella capitata (Polychaeta, Annelida)
Authors: Bhup Rohan , Marsden Joan R.
Published: August 2008

The development of the central nervous system of the polychaete Capitella capitata is described in a series of five stages, using both light and electron microscopy. The initial cerebral primordium is paired and differentiates into two cell types, one electron lucent and granular, the other electron dense. The onset of muscular activity precedes the initiation of axonal growth. Neural differentiation appears to progress anteroposteriorly. Earliest morphological indications of neuromuscular contact are found in the metatrochophore stage. Classically differentiated synaptic junctions were not seen, even in the final settling stage. Development in C. capitata is essentially direct; there are very few larval features and none of these concern the emerging nervous system.
Male reproductive behaviour and spawning success in a temperate zone goby, Coryphopterus nicholsi
Authors: Cole Kathleen S.
Published: August 2008

Coryphopterus nicholsi is a temperate zone marine goby. In laboratory groups of fish, females preferentially spawn with dominant males; assessment of dominance appears to be based upon courting vigour. Male size (standard length) and dominance were often, but not always, highly correlated. In contrast, there was no consistent correlation between territorial quality and spawning success. Smaller males in laboratory groups did not court females or guard eggs. However, their behaviour and testicular development during the reproductive season suggest that they may engage in sneak spawning. Dominant males are more likely to successfully guard eggs against conspecific predators than are subordinate males, and hence females should have greater reproductive success if they choose dominant males for spawning partners.
Production ecology of Hexagenia limbata in Savanne Lake, Ontario
Authors: Riklik Louis , Momot Walter T.
Published: August 2008

The population dynamics of the burrowing mayfly Hexagenia limbata was examined in Savanne Lake, a small, shallow, dark-water lake in northwestern Ontario. Hexagenia limbata in Savanne Lake has a 2-year life cycle with a larger cohort emerging on alternate years. The mean biomass [Formula: see text] varied from 0.36 g/m2 (wet weight) to 2.98 g/m2, while mean numbers varied from 34/m2 to 121/m2. Annual production (P) was calculated from samples collected monthly during the period of growth for 1979 and 1980. The Allen curve, instantaneous growth, and size frequency methods estimated annual production as 4.80, 4.78, and 5.59 g/m2 (wet weight), respectively. The corresponding annual P/B ratios calculated by the three methods were 2.1, 2.1, and 2.6.
The morphology of the kidney in young adult anadromous sea lampreys, Petromyzon marinus L., adapted to seawater. II. Distal and collecting segments, the archinephric duct, and the intertubular tissue and blood vessels
Authors: Youson John H.
Published: August 2008

Gradual acclimation of young adult anadromous sea lampreys, Petromyzon marinus L., to full-strength (100%) seawater results in changes in the morphology of the distal and collecting segments, the archinephric duct, and the intertubular tissue and blood vessels. The alterations first appear in animals in 60% seawater and mainly are represented by a luminal precipitate in the distal and collecting segments and increased numbers of cytoplasmic granules in the cells of these segments. Luminal debris of degradating cells, concentric rings of an amorphous material, or a crystalline material is characteristic of distal segments from animals adapted to 80% seawater and it is accompanied by flattening of the epithelium and a further granulation and a vacuolation of the cytoplasm. The above features are present to a lesser extent in the collecting segment. In 100% seawater, further flattening, vacuolation, granulation, and apparent degeneration of distal cells occurs and there are many more small-diameter renal tubules. Granulation of endothelial cells of efferent arterioles in animals at concentrations of 80 and 100% may indicate that these cells are recruited to absorb macromolecules. The tubular interstitium at these two highest salinities possesses many cells involved in the phagocytosis of red blood cells. The morphological transformation of the renal cells indicates that young adult anadromous P. marinus may have some difficulty in osmoregulating in hyperosmotic environments.
Analysis of variation in the Elaphrus finitimus complex of North America (Coleoptera: Carabidae)
Authors: Goulet Henri , Baum Bernard R.
Published: August 2008

This is a continuation of a study on geographical variation of the Elaphrus americanus Dejean species complex. This paper is devoted to E. finitimus Casey, which includes at least seven populations: White Mountains of California, Colorado Plateau, western Great Basin, western Arizona, central California, southern California, and southern Sierra Nevada. Three main groups of populations were recognized by means of numerical taxonomic analyses: White Mountains of California (one population), Intermontane (Colorado Plateau and western Great Basin), and southwestern (remaining four populations). The above groups were discerned from clustering by UPGMA (unweighted pair group using arithmetic averages) of Mahalanobis distances, and are characterized in a discriminant analysis. Other geographically distinct populations were recognized by univariate analysis of nominal characters. All seven populations are allopatric and are isolated presently from one another by vast expanses of dry regions (prairies and piñon–juniper woodlands), or by different life zones with altitude. We postulated that during the glacial phases of the Pleistocene similar barriers existed, though the gaps were narrower than at present. The reconstructed glacial ranges of these populations offer a hypothesis as to the origin of some populations, and direction of limited gene flow between some populations.
The histology, ultrastructure, and histochemistry of the ventral surfaces of Catatropis verrucosa (Froelich, 1789) Odhner, 1905 and Paramonostomum alveatum (Mehlis in Creplin, 1846) Lühe, 1909 (Digenea: Notocotylidae)
Authors: MacKinnon Barbara M.
Published: August 2008

Catatropis verrucosa (Froelich 1789) Odhner 1905 and Paramonostomum alveatum (Mehlis in Creplin, 1846) Lühe 1909 were examined using light and scanning and transmission electron microscopy. The ventral ridge, papillae, and body margins of C. verrucosa contained numerous pyriform cells packed with mitochondria. Paramonostomum alveatum has no ventral projections and no pyriform cells full of mitochondria were seen within the worms. Both species contained numerous large electron-dense inclusions in various tissues throughout the body. Histochemistry indicated that these inclusions were lipid or lipoprotein, but their function is unknown. Protein, including haemoglobin, and lipid were identified within the pyriform cells of C. alveatum. Paramonostomum is the only genus within the Notocotylinae examined to date that has no ventral projections nor any internal aggregation of cells packed with mitochondria.
A quantitative method for bovid horn classification
Authors: Mloszewski M. J.
Published: August 2008

A quantitative method for the classification of bovid horns and horn-cores is proposed. Selected horn characteristics are expressed as ratios of intercepts along three mutually perpendicular reference axes of which one is anteroposteriorly orientated and tangent to the frontal bone midway between the horn bases. Horns can be compared interspecifically and intraspecifically without regard to their actual size. All bovid horns may be classified, by immediate inspection, into one of four classes, from least to most complex, under the proposed system. The notation identifies the class and provides means of comparing individuals within it. The actual horn length may be included as an additional parameter, to permit conversions. Other parameters (e.g., horn thickness) can be added when needed without interfering with the formula.
Initiation and termination of macronuclear DNA synthesis in Paramecium: effect of variation in macronuclear DNA content
Authors: Berger James D.
Published: August 2008

The timing of both initiation and termination of DNA synthesis was examined in Paramecium cells with an unusually wide range of DNA contents. Variation in DNA content was increased through the action of a mutant gene, tamG, which interferes with macronuclear amitosis. The major conclusions are (1) timing of initiation of DNA synthesis is unaffected by G1 macronuclear DNA content and (2) the duration of the S phase of the cell cycle increases only slightly with increasing macronuclear DNA content. Since Paramecium cells with increased DNA content do not synthesize increased amounts of DNA, the present observations imply that the absolute rate of increase in DNA content remains constant, while the relative rate of DNA synthesis (rate per unit DNA) decreases as initial DNA content increases. The implications of these conclusions for regulation of macronuclear DNA content, cell mass, and cell cycle duration are discussed.
Size and fecundity of adult Simuliidae (Diptera) as a function of stream habitat, year, and parasitism
Authors: Colbo M. H.
Published: August 2008

Adult Prosimulium mixtum, Cnephia ornithophilia, and Stegopterna mutata, whose larvae develop during the winter, varied in size and fecundity between streams, within the same stream, and between years. In P. mixtum the greatest variation in the same year between sites was a fivefold difference in the mean fecundity, and between years at the same site a twofold change was observed. Size of males and females of P. mixtum and C. ornithophilia were equally affected by the environment. Effects of mermithid nematodes in the Simulium venustum complex and an ovarian fungus in St. mutata were also investigated. The fungus and one mermithid population did not affect the size of the female flies while the second mermithid population with a different development pattern did decrease the size of the flies. These results are discussed in relation to the ecology and control of Simuliidae.
Ophioxenos lampetrae sp. nov. (Digenea: Paramphistomidae) from ammocoetes of the western brook lamprey (Lampetra richardsoni Vladykov and Follett) in British Columbia, with comments on lamprey host–parasite relationships
Authors: Beverley-Burton M. , Margolis L.
Published: August 2008

Ophioxenos lampetrae sp. nov. (Digenea: Paramphistomidae) from the intestine of ammocoetes of the western brook lamprey (Lampetra richardsoni) in British Columbia, Canada, is described. It is distinguished from other members of the genus, O. dienteros and O. singularis (parasites of reptiles, primarily garter snakes, and amphibians in North America), by having relatively few vitelline folicles of limited anterior extent and a voluminous uterus filling most available intercaecal space. This appears to be the first record of a digenean utilizing a petromyzontid as a definitive host. Some aspects of lamprey host–parasite relationships are discussed.
Relaxed regulation of Dermacentor variabilis (Say) in Nova Scotia
Authors: McEnroe W. D.
Published: August 2008

The development cycle of Dermacentor variabilis (Say) in Nova Scotia allows the full production of diapause larvae from the spring adult breeding period. The overwinter stages, larvae and adults, cope with the harsh winter environment. The shift from the two cohort life cycle of D. variabilis in New England to the one cohort cycle in Nova Scotia removes the regulation involved in the passage from the spring adult cohort to the summer adult cohort.
L'oeuf de Bruchidius atrolineatus (Pic) et son système de fixation
Authors: Biémont J. C. , Chauvin G. , Germain J. F.
Published: August 2008

Scanning electron microscope studies of eggs of Bruchidius atrolineatus were made and the system of egg fixation on cowpea pods (Vigna unguiculata Walp) was described. The egg is fusiform and asymmetrical. Its upper part is convex and polygonal structures are present. Its lower surface is flat and exhibits small protuberances. The convex side is 8 μm thick whilst the flat side is only 1 μm thick. A strengthened band-like zone separates the convex side from the lower part of the egg. When laid, the egg is coated with a sticky mucus-like substance. This substance hardens when entering stomata of the pods. An efficient egg-fixation system thus covers the stomata.
Communication among territorial female spruce grouse
Authors: Nugent D. P. , Boag D. A.
Published: August 2008

Behaviour associated with territoriality in female Franklin's spruce grouse (Canachites canadensis franklinii) was studied during the breeding seasons of 1976 and 1977 to determine how and when these grouse communicate their location to conspecifics and what role communication has in maintaining dispersion. Field observations of marked grouse indicated that resident females advertised their presence to conspecifics and probably maintained their territories by producing both vocal and nonvocal sounds that peaked in intensity during the period of mating and laying. These sounds included a Cantus ("aggressive call") that was sung from regularly used advertising perches at dawn and dusk and flight sounds produced by flying frequently through the territory at these times. The Cantus was also used by territorial females during interactions with both trespassing nonterritorial and contiguous territorial females. The territorial behaviour of breeding females, manifested by intrasexual aggression, appeared to play a role in spacing of nests and spring dispersal of some yearlings.
A new species of dorid nudibranch (Opisthobranchia: Mollusca) belonging to the genus Anisodoris
Authors: Millen Sandra V.
Published: August 2008

A new species of Anisodoris (Opisthobranchia: Mollusca) is described. It is found in shallow, subtidal, rocky areas in southern British Columbia, Canada. This species is characterized by its large size, by its white or creamy ground colour with large brown blotches on the dorsum, and by the scalloped, platelike spines on its penis. Its spawn and embryological and larval development are described. The taxonomic status of this species is discussed in relation to genera in the family Discodorididae. The new species is compared with all known species of the genus Anisodoris.
Effects of temperature and salinity on immature and juvenile Neomysis americana (Smith) (Crustacea; Mysidacea)
Authors: Pezzack D. S. , Corey S.
Published: August 2008

The temperature and salinity tolerance of newly released young Neomysis americana was measured for two acclimation temperatures and salinities. The newly released young possess a wide tolerance range to changes in temperature and salinity. Salinities as low as 4‰ had no effect on the molt or growth rate. The effect of environmental conditions on the distribution and life history are discussed.
Classification of nine species and subspecies of tsetse flies (Diptera: Glossinidae: Glossina Wiedemann) based on molecular genetics and breeding data
Authors: Gooding R. H.
Published: August 2008

Adults from nine taxa of tsetse flies (Glossina) were examined by polyacrylamide electrophoresis, and banding patterns for 12 enzymes were determined and interpreted in terms of allele frequencies. Tetrazolium oxidase and manganese-stimulated malic acid dehydrogenase were monomorphic in each taxon. Arginine phosphokinase, glucose-6-phosphate dehydrogenase, and an esterase from testes were controlled by X-chromosome loci. Seven enzymes (xanthine oxidase, aldehyde oxidase, octanol dehydrogenase, an esterase, an α-glycerophosphate dehydrogenase, malic acid dehydrogenase, and alkaline phosphatase) were controlled by autosomal loci. With the exception of Glossina morsitans submorsitans, members of the morsitans group had higher average heterozygosity per locus than did members of the palpalis group. A phenogram, based on mean genetic identities, placed G. austeni in the palpalis group, rather than in the morsitans group. Electropherograms indicated substantial genetic differences between G. m. submorsitans and other subspecies of G. morsitans sensu lato. A strong postmating barrier prevented hybridization of G. m. submorsitans (originating from Upper Volta) with G. m. morsitans and G. m. centralis. Using the X-chromosome loci ocra and salmon as markers, genetical recombination was not observed in hybrids of G. m. morsitans and G. m. centralis.
Regulation of hemolymph amino acid levels and active secretion of proline by Malpighian tubules of locusts
Authors: Chamberlin M. E. , Phillips J. E.
Published: August 2008

Levels of individual and total (40–50 mM) amino acids remained relatively constant in locust hemolymph despite 50% changes in hemolymph volume during hydration and dehydration: proline, glycine, and glutamine constituted 70% of the total. Likewise, amino acid levels in tubular fluid did not change substantially during osmotic stress: proline constituted 80% of the total. Most hemolymph amino acids (P) appeared at lower concentrations in the tubular fluid (U); however, U/P ratios for glutamate and proline were 5.8 and 3.2, respectively. These results suggest that neutrally charged proline is actively transported by locust tubules, and this was confirmed by further experiments in vitro. Secreted proline is actively reabsorbed in the rectum where it probably serves as the principal substrate for oxidative metabolism in this tissue.
Energy distribution in biomass estimates within a freshwater bivalve community
Authors: Paterson C. G.
Published: August 2008

In an association of the bivalves Elliptio complanata, Anodonta cataracta, and Lampsilis ochracea in a New Brunswick lake, the distribution of standing stock biomass is among tissue (64.6%), shells of living individuals (19.4%), and empty shells and shell fragments (16.0%). Failure to consider the latter two energy compartments would result in serious underestimates of standing stock biomass.
The spatial distribution of singing and foraging in the territories of white-throated sparrows
Authors: Wasserman Fred E.
Published: August 2008

Fourteen territorial male white-throated sparrows, Zonotrichia albicollis, were observed to determine the spatial distribution of their singing and foraging activities. Both activities were concentrated toward the geographic activity center of the territory with singing occurring significantly closer to the center than foraging.