bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth, maturation, and apparent and absolute fecundity of creek chub, Semotilus atromaculatus (Mitchill), in the Kawartha Lakes Region, Ontario
Authors: Powles P. M. , Parker Douglas , Reid Ronald
Published: August 2008

No difference in growth rate occurred between two study streams, but male creek chub grew more rapidly than females, to a maximum reached at 7 years of age. Walfords were as follows: y = 4.8 TL + 0.810x, females; y = 3.5 TL + 0.792x, males. The length–weight relationship, W = −3.609 + 2.925 log L (TL), derived in the fall, was, as expected, somewhat below the spring relationship from an Illinois study. Kawartha creek chub M50 values were 6.0 TL ± 0.83 cm (males) and 6.54 ± 0.18 cm (females). Relative or apparent fecundity (fall egg count) was F = 71.9 + 136W and total or absolute fecundity (just before spawning) was virtually similar to other areas at F = 61.6 + 91.8W.
The effect of hypophysectomy and prolactin treatment on the osmotic water influx into the isolated gills of the Japanese eel (Anguilla japonica)
Authors: Ogawa Mizuho
Published: August 2008

An in vitro technique has been used to measure the osmotic water influx into the isolated gills and the osmotic permeability of the gill surface of the Japanese eel, Anguilla japonica. Hypophysectomy increases both of these measurements. Prolactin injections decrease both osmotic water influx and osmotic permeability to water in both the intact and hypophysectomized eels in fresh water but produce no change in either of these parameters when the fish (either intact or hypophysectomized) are in sea water. The possible role of the pituitary (especially prolactin) in osmoregulation of fishes is discussed and considered in relation to the environmental calcium in sea water.
Seasonal variations in calorific values of some littoral benthic invertebrates of the Ottawa River, Ontario
Authors: Rodgers D. W. , Qadri S. U.
Published: August 2008

The calorific values of several groups of littoral benthic invertebrates of the Ottawa River varied significantly from June to September 1974. Observed variation over this period amounted to 8% of the minimum calorific value in the amphipod Gammarus fasciatus (3934–4258 cal/g dry weight), 19.5% of the minimum calorific value in the amphipod Hyallela azteca (3611–4315 cal/g dry weight), 22.4% of the minimum calorific value in the isopods of Asellus spp. (3252–3981 cal/g dry weight) and 12.1% of the minimum calorific value in midge larvae, Chironomidae spp. (4176–4737 cal/g dry weight). Two patterns of change in calorific value were observed. In G. fasciatus and Asellus spp. significant (p ≤ 0.05) variations were noted in both calorific value (calories per gram dry weight) and the relative size of the ash fraction (percentage ash) but not in the calorific value of the organic fraction (calories per gram ash-free dry weight). In H. azteca and Chironomidae spp. larvae, variation in all three parameters was significant (p ≤ 0.05).
Feeding rates, search paths, and surveillance for predators in great-tailed grackle flocks
Authors: Smith James N. M.
Published: August 2008

Feeding rates, search paths, and surveillance behaviour of great-tailed grackles were measured to test the hypotheses that flocking influences: (a) feeding rates, (b) search behaviour, and (c) predator detection.Peck rates of grackles feeding on open grass meadows in Gatun, Panamá Canal Zone, did not vary with flock density and variation in peck rates was also independent of density. When grackles were in denser flocks, their search paths were straighter and, during the wet season only, they moved slower in denser flocks. Female grackles in denser flocks paused less often to scan the surrounding environment, presumably for potential danger.Although they were not strongly influenced by flocking, feeding and search behaviour of grackles was strongly affected by the sex of the grackles, the season, and the local feeding area. Grackle feeding behaviour hence seemed less closely adjusted to flocking than to other environmental factors.
Zooplankton and zoobenthos communities of selected northern Ontario lakes of different acidities
Authors: Roff J. C. , Kwiatkowski R. E.
Published: August 2008

The zooplankton and zoobenthos were investigated in six lakes in the Sudbury area of Ontario in which pH values lay between 4.05 and 7.15. Zooplankton showed a significant reduction in species and numbers at the lower pH levels; the Rotifera showed the greatest changes. Zooplankton diversity index (DI) declined sharply below pH 5.3. Percentage similarity of community (PSc) and coefficient of community (CC) values were highest between lakes closest in pH, reflecting progressive changes in species composition.Significant relationships were found between the zooplankton standing crop and chlorophyll a concentrations and the zooplankton standing crop and areal primary productivity. Dry weights for Holopedium gibberum and Diaptomus minutus were lowest in the most acidic lakes. No significant relationship between body length or egg ratio, and lake pH were found for D. minutus.The zoobenthos was represented by a variety of taxa; however, only genera belonging to the Oligochaeta and Tendipedidae were represented in all study lakes. Zoobenthos DI showed only a slight decrease below a pH of 4.9. PSc and CC values for the zoobenthos displayed similar though not as distinct patterns as those found in the plankton.
Synthesis, storage, and release of MSH in the pars intermedia of the pituitary gland of Xenopus laevis during background adaptation
Authors: Jenks B. G. , VanOverbeeke A. P. , McStay B. F.
Published: August 2008

Pituitary levels of melanophore-stimulating hormone (MSH), release of MSH, and protein synthetic activity in the pars intermedia were determined in Xenopus laevis during background adaptation. MSH was measured using a radioimmunoassay to α-MSH; uptake of [3H]lysine, determined autoradiographically, was used to assess protein synthesis; changes in melanophore index indicated changes in release of MSH. Adaptation to black background led to eventual depletion of MSH and increased protein synthetic activity. Conversely, during adaptation to a white background MSH levels increased and protein synthesis decreased. Changes in synthesis lagged considerably behind changes in release. During the initial stage of black-background adaptation, release of MSH was not accompanied by simultaneous decrease in levels of MSH in the gland from which it is concluded that replenishment of MSH took place. Our results indicated that this replenishment in the gland could not be accounted for by de novo synthesis of the hormone. It is proposed that a stored precursor to MSH exists, conversion of which provides for rapid replenishment of MSH. It is suggested that the factor(s) controlling MSH release affect synthesis of this hormone only indirectly.
Reproductive correlates of the hip gland in voles (Microtus townsendii)
Authors: MacIsaac Gary L.
Published: August 2008

The behaviour of hip glands, as gauged by gland length, in Microtus townsendii is shown to be highly correlated with reproductive condition in both males and females. Breeding voles of both sexes are shown to have larger hip glands than nonbreeding voles. It was shown that the hip glands of male Microtus townsendii are under androgen control. The first known observations of marking behaviour in M. townsendii are described.
Three new Eimeria spp. (Protozoa, Eimeriidae) from muskoxen, Ovibos moschatus, with redescriptions of E. faurei, E. granulosa, and E. ovina from muskoxen and from a Rocky Mountain bighorn sheep, Ovis canadensis
Authors: Duszynski D. W. , Samuel W. M. , Gray D. R.
Published: August 2008

Oocysts of Eimeria moschati sp.n., Eimeria oomingmakensis sp.n., and Eimeria ovibovis sp.n. are described from muskoxen (Ovibos moschatus) in the United States (Alaska), Canada (Alberta, Northwest Territories, Quebec), and Norway. Oocysts of Eimeria faurei (Moussu and Marotel, 1902) Martin, 1909, Eimeria granulosa Christensen, 1938, and Eimeria ovina Levine and Ivens, 1970 are redescribed from muskoxen and from a Rocky Mountain bighorn sheep, Ovis canadensis, from Montana. Ellipsoid oocysts of E. moschati are 17–25 × 15–21 (20.5 × 17.4) μm with ovoid sporocysts 9–12 × 5–7 (10.8 × 6.1) μm. A micropyle, micropyle cap, multiple polar bodies, Stieda bodies, and sporocyst residua are present. Oocysts of E. oomingmakensis are ellipsoid, 38–61 × 28–38 (47.5 × 33.7) μm with ellipsoid sporocysts 18–23 × 9–12 (20.4 × 10.5) μm. A micropyle, Stieda and substieda bodies, and sporocyst residua are present. Ellipsoid oocysts of E. ovibovis are 20–25 × 16–21 (22.9 × 18.8) μm with ellipsoid sporocysts 11–15 × 5–7 (12.7 × 6.0) μm. A micropyle, Stieda bodies, and sporocyst residua are present. Similarities between these six species and all other Eimeria spp. from ruminants are discussed.
Appendicular abnormalities in the milliped family Xystodesmidae (Polydesmida)
Authors: Shelley Rowland M.
Published: August 2008

Abnormalities of male gonopods and nonsexual appendages in the milliped family Xystodesmidae include hysterotely, heteromorphosis, polymely, and segments with reduced numbers of legs owing to modified sterna. One bizarre appendage at the normal reproductive position possesses both ambulatory and gonopodal segments, proving that a gonopod is a modified leg which is specialized for copulation. The presence of accessory gonopods at atypical locations does not affect the pair at position 8, and in all reported cases the latter are normal. Likewise, it is possible to have a normal leg or gonopod opposite an abnormal appendage. An aberrant specimen of Harpaphe haydeniana cummingsiensis (Verhoeff) with an accessory gonopod also possesses deformed paranota and a large, tumorlike growth from the fourth metazonite.
Interisland movements of Peary caribou (Rangifer tarandus pearyi) on western Queen Elizabeth Islands, Arctic Canada
Authors: Miller Frank L. , Russell Richard H. , Gunn Anne
Published: August 2008

To verify that Peary caribou were making seasonal interisland movements, we used an aerial dye-spray method. In April 1974, about 230 caribou were dye-marked green, and about 200 were marked red on Prince Patrick and Eglinton islands respectively. Aerial searches in June and July 1974 located 41 sightings of dye-marked animals. Of animals marked on Prince Patrick Island 4 were seen on Melville Island, 3 on Eglinton Island, and 16 on Prince Patrick. Of sightings of animals marked on Eglinton Island, there were 6 on Prince Patrick Island and 12 on Eglinton. Maximum distance travelled (vector sum on horizontal plane) by marked caribou was 450 km, from Prince Patrick Island to eastern Melville Island. The study indicates that high proportions of the caribou population seasonally range over two or more islands of the western Queen Elizabeth Group. Therefore, complete evaluation of annual range requirements on an island basis should take into consideration seasonal changes in numbers of caribou that are due to interisland movements.
Influence of combinations of bovine growth hormone, 17α-methyltestosterone, and L-thyroxine on growth of yearling coho salmon (Oncorhynchus kisutch)
Authors: Higgs David A. , Fagerlund Ulf H. M. , McBride Jack R. , Dye Helen M. , Donaldson Edward M.
Published: August 2008

Groups of yearling coho salmon held at 10 °C on a natural photoperiod, and fed excess ration daily, were administered either bovine growth hormone (bGH; 0.0092 IU/g body weight), L-thyroxine (T4; 1 μg/g), 17α-methyltestosterone (MT; 1 mg/kg diet), combinations of these hormones, or no hormone for 59 days. Fish received bGH and (or) T4 intramuscularly once weekly.Each individual hormone and hormone combination significantly enhanced growth. The sequence noted for growth rate of the groups was as follows: (bGH + MT + T4) > (bGH + MT) > (bGH + T4) > bGH > (T4 + MT) > MT > T4 > control groups. Three hormonal interactions were additive (T4 + MT; bGH + MT; bGH + MT + T4). The growth rate of fish treated with bGH + MT + T4 was over three times that of the controls.T4 or MT + T4 administration significantly increased condition factors, while MT, bGH, bGH + T4, bGH + MT, and bGH + MT + T4 decreased them.Significant elevations in percentages of muscle water (bGH) and lipid (T4; T4 + MT; bGH + MT) were found. Thyroid activity (follicle epithelial height) was significantly increased in MT and MT + bGH fish, but depressed in T4 fish. Hormone administration altered the histological structure of the endocrine pancreas (bGH and MT groups), ovary (bGH; MT groups), testis (MT groups), and interrenal tissue (bGH; MT).
Morphometric changes in an elasmobranch (Squalus acanthias) after preservation
Authors: Jones Barry C. , Geen Glen H.
Published: August 2008

Length, weight, and volume of eggs, embryos, and postembryonic spiny dogfish (Squalus acanthias) up to 83 cm long were differentially affected when frozen or kept in 5% formaldehyde solutions of different salinities. Deviations from measurements in the unpreserved condition were greater with longer periods of storage and larger fish size. Morphometric changes were similar to those for teleosts at small sizes, but less at larger sizes.
Morphology and host specificity of Cryptobia catostomi n.sp. (Protozoa: Kinetoplastida) from white sucker (Catostomus commersoni) in southern Ontario
Authors: Bower Susan M. , Woo Patrick T. K.
Published: August 2008

During the summer of 1975, 285 white sucker from 10 localities in southern Ontario were examined for haemoflagellates. Cryptobia catostomi n.sp., found in the blood of 43.4% of the fish examined, occurred in all populations of adult fish and in one of three populations of juvenile fish.The morphology of C. catostomi n.sp. based on over 500 specimens stained with Giemsa's stain, varied considerably. Cloning showed that this species is pleomorphic and has morphological features and body measurements which encompass most other Cryptobia spp. previously described from the blood of fishes. Cryptobia catostomi n.sp. was distinguished by its host specificity. Infections could not be transmitted to 16 other species of fishes by inoculation of blood from infected sucker. Fishes refractive to infection included Cyprinus carpio, Carassius auratus, Rhinichthys atratulus, Semotilus atromaculatus, Salmo gairdneri, Oncorhynchus kisutch, and Esox lucius from which other species of Cryptobia (C. borreli, C. cataractae, C. salmositica, and C. gurneyorum) have been reported in North America.
Division and morphogenesis of Cryptobia catostomi (Protozoa: Kinetoplastida) in the blood of white sucker (Catostomus commersoni)
Authors: Bower Susan M. , Woo Patrick T. K.
Published: August 2008

Cryptobia catostomi multiplied in the blood of the white sucker (Catostomus commersoni) by longitudinal binary fission. The first indication of division was the production of two flagella followed by incomplete nuclear division. By this time the blepharoplast had divided. Each daughter blepharoplast, which gave rise to an old and a new flagellum, migrated to either end of the body. The kinetoplast then divided. The chromatin strand connecting the two nuclei disappeared and the organism completed division giving rise to two specimens.By following the course of infection in a mature white sucker it was observed that type III specimens were most abundant when the parasite population was increasing. As the population leveled off to a plateau, the numbers of type III decreased and were replaced by type II and eventually type I specimens.
A preliminary investigation of the effects of diets on lesion formation in the hindgut of adult female American cockroaches
Authors: Bignell David E. , Mullins Donald E.
Published: August 2008

A preliminary investigation of the general relationships between different levels and sources of dietary nitrogen and lesion formation in the alimentary canal of adult female American cockroaches, Periplaneta americana (L.), has been conducted. Increasing levels of casein protein in the diet could not be clearly correlated with an increased incidence of lesions, but very high casein protein levels produced gross tissue abnormalities in the hindgut. Diets containing casein hydrolysate appeared to enhance lesion formation. When 1% additions of kynurenic acid, xanthurenic acid, tryptophan, and uric acid were made as supplemental sources of nitrogen, lesions appeared in a greater number of animals. Except in the case of uric acid, these spiked diets resulted in a lower total lesion area than when the nitrogen source was casein hydrolysate alone. Additions of an antibiotic, neomycin, to casein hydrolysate diets resulted in a lower level of lesion-forming activities.Lesion formation which was enhanced by dietary means appeared to result from an inflammatory reaction involving hemocytes. It is proposed that these inflammations were caused by high ammonia concentrations and irritant bacterial metabolites present in the gut lumen. No evidence was found to indicate that oxyuroid nematodes contributed to hindgut lesion formation.
Anatomy of the intestine of Ascaris suum: a three dimensional study with silicone rubber casts
Authors: Harpur Robert P.
Published: August 2008

To facilitate studies of the physiology of Ascaris suum the relations between the intestine and the other organs were investigated. The anterior intestine, which starts, with a thin-walled expansion chamber, is held by connective tissue and by the bellies of muscle cells. A coarctation of the intestine marks the junction of the anterior and midintestine and in the female this narrowing occurs near the genital pore. The midintestine lies free amongst the reproductive organs and terminates near the most posterior excursions of the ovaries and uteri in the female, and of the testis in the male. The posterior intestine is attached continuously, but not initially circumferentially, to the body wall. Relative lengths for the different parts of the female worm are given and microfil casts made in situ with both sexes yielded information about the relative volumes of the midintestine and posterior intestine. The coarctation is the narrowest pan of the intestine and the largest cross-sectional area is reached at the start of the posterior intestine. The attachments to the body wall indicate that the anterior and posterior intestine change length like an accordion when the muscles contract but the cross-sectional area of the lumen is decreased by dorsoventral compression.
Effects of temperature acclimation on infection of Echinocephalus sinensis (Nematoda: Gnathostomatidae) from oysters to kittens
Authors: Ko Ronald C.
Published: August 2008

About 700 oysters (Crassostrea gigas) were acclimated in the laboratory to 33, 28, 20–24, 15, and 5 °C. Third-stage larvae of Echinocephalus sinensis Ko, 1975 recovered from the tissues of these molluscs were fed to 31 kittens which were examined 18 h postinfection. The number of successful infections produced and the number of worms located in tissues of kittens were found to be directly related to the ambient temperature of the molluscan host. Substantial infections were obtained only with worms from 33 and 28 °C. Worms could be effectively killed if the infected oysters were deep fried with batter for 7 s or dipped in boiling water for 30 s. The possibility of finding other nematodes of poikilotherms similar to E. sinensis in the tropics is briefly discussed.
Some aspects of overwintering in the chipmunk, Eutamias amoenus
Authors: Stebbins Lucius L. , Orich Reginald
Published: August 2008

Seasonal changes in size, food consumption, and activity were measured in Eutamias amoenus housed in cages with nest boxes and exposed to seminatural meteorological conditions at Lethbridge, Alberta, Canada. Decreases in food consumption, activity, and size were recorded in winter months. Results suggest reduced growth and activity in winter are effective mechanisms of energy conservation in this species.
A fencing experiment on a high-density population of Microtus townsendii
Authors: Boonstra Rudy , Krebs Charles J.
Published: August 2008

If dispersal is prevented, a low-density vole population will increase to unusually high densities. A mouse-proof fence was constructed around a vole population that had already reached high density and both this population and one on a control area were live-trapped from January 1975 to November 1975. The population on the control remained at peak densities. The enclosed population increased to even higher density once the breeding season had started and had a higher survival rate than the control population. By midsummer the enclosed population had severely overgrazed the vegetation and went into a sharp decline. Dispersal losses from the control were estimated at 32% for males and 31% for females in these high-density populations. Microtus townsendii populations thus responded to a fence in a manner similar to that of other species that have been studied. This experiment indicates the importance of dispersal to population regulation in voles even at peak densities.
Diurnal and seasonal activity of the grey squirrel (Sciurus carolinensis)
Authors: Thompson D. C.
Published: August 2008

The diurnal and seasonal activity of the grey squirrel is quantified. A single midday peak occurs in the winter. This peak is displaced into morning and afternoon activity peaks as the length of daylight increases. The activity of individuals is highest in the summer. Females are significantly more active than males during spring and summer.
The ectoparasites of three species of seabirds from Newfoundland, Canada
Authors: Fitzpatrick Charles , Threlfall William
Published: August 2008

Two groups of ectoparasites, namely Mallophaga and Acarina, were recovered from 47 Larus argentatus, 29 Rissa tridactyla, and 18 Oceanodroma leucorhoa taken on Gull Island, Witless Bay, Newfoundland, during the period June–August 1974. Mallophaga of the genera Saemundssonia and Quadraceps (Ischnocera) were found to be common ectoparasites of both L. argentatus and R. tridactyla and the genera Halipeurus (Ischnocera) and Austromenopon (Amblycera) were recovered from O. leucorhoa. A single ixodid tick, Ixodes (Ceratixodes) uriae, was recovered from an R. tridactyla chick. Only O. leucorhoa were found to harbour feather mites, these belonging to the genera Zachvatkinia, Brephosceles, Connivelobus, and Ingrassia.Details on the degree of infestation of the birds are given as well as the distribution of each ectoparasite species on the hosts.
Acoustic and behavioural analyses of the sounds produced by some species of Nearctic Arctiidae (Lepidoptera)
Authors: Fullard J. H. , Fenton M. B.
Published: August 2008

Seventeen of the 24 species of Nearctic Arctiidae which we examined produced sounds under a variety of tactile and acoustic stimuli. Seven of 14 sound-producing species tested emitted their sounds in response to the hunting cries of insectivorous bats or simulations thereof. The sounds were generated by the buckling action of the microtymbal band (=striated band) on the surface of the modified thoracic metepisternum (=tymbal). Sound production is not dependent on the presence of microtymbals as four species of Callarctia possessed nonstriated, functional tymbals. In contrast, other species possessed striated, apparently nonfunctional tymbals.The sounds of the arctiids we studied were predominantly ultrasonic (> 20 kHz) and relatively faint (< 85 dB at 2 cm) compared with other insect sounds.The acoustic parameters of the arctiids surveyed revealed extremely high levels of variability in the sounds. Smaller species generally emit higher pulse repetition rates and more intense signals than larger ones. The behavioural contexts in which the sounds are produced and their relation to arctiid defense are discussed.
Reproductive potential in parkland- and arctic-nesting populations of mallards and pintails (Anatidae)
Authors: Calverley B. K. , Boag D. A.
Published: August 2008

We estimated the reproductive potential of mallards (Anas platyrhynchos) and pintails (A. acuta) nesting in the parklands of Alberta and the delta of the Mackenzie River, N.W.T., by recording the number of laying females and the potential clutch size, based on the status of ovarian follicles, in samples of each species collected at the two latitudes. A larger proportion of the ducks collected in the parklands were laying and their potential clutch sizes were larger than in the arctic. Thus, both species exhibited a greater reproductive potential in the parklands than in the arctic. The reasons for these differences are discussed in relation to energy costs to ducks breeding at the two latitudes.
Harem size, territory quality, and reproductive success in the redwinged blackbird (Agelaius phoeniceus)
Authors: Weatherhead Patrick J. , Robertson Raleigh J.
Published: August 2008

The relationships between harem size, territory size, nest site suitability, and fledging success were studied for a breeding population of redwinged blackbirds (Agelaius phoeniceus). Reproductive success was correlated negatively with female breeding density within territories and positively with territory quality as determined from nest site parameters. Harem size was not correlated with differences in either territory area or quality. From these results we suggest that some females were attracted to nest in territories in which their chances of successful reproduction were lower than if they had chosen other available territories. To explain the selective advantage of such choices, we postulate that females were choosing mates which would enhance their ultimate fitness rather than their immediate reproductive success.
Effect of weather factors on spiders (Araneida) in an Ontario meadow
Authors: Dondale C. D. , Binns M. R.
Published: August 2008

In a 5-year investigation, population densities of spiders and associated arthropods were measured in a meadow by 'quick trap' and vacuum sampler. Analysis using empirical regression equations indicated that seasonal changes in spider numbers were largely explainable by weather factors, particularly cumulative temperature. Rainfall was also important, even on the moister, well vegetated part of the meadow. Much of the residual variability could be accounted for by the inclusion in the equations of other categories of arthropods such as Cicadellidae, Collembola, and Staphylinidae.
Effects of dexamethasone and metopirone on ovulation in the goldfish, Carassius auratus
Authors: Pandey S. , Lam T. J. , Nagahama Y. , Hoar W. S.
Published: August 2008

At 12 ± 1 °C, a temperature at which goldfish will not ovulate, metopirone induced ovulation in gravid fish. Histological analysis revealed marked stimulation of the pituitary–interrenal axis but did not reveal any change in stainability (granulation) or nuclear size of gonadotrops. It is suggested that metopirone induced ovulation in goldfish by stimulating secretion of 11-deoxycortisol and (or) 11-deoxycorticosterone. Other possibilities are discussed.When the ambient temperature was gradually raised to 20 ± 1 °C, dexamethasone treatment blocked the ovulatory response consistently seen in the saline-injected controls. However, fish injected with human chorionic gonadotropin in addition to dexamethasone ovulated like the saline-injected controls. No change in stainability (granulation) was seen in gonadotrops of dexamethasone-treated fish (20 ± 1 °C) compared to saline-injected and uninjected controls held at 12 ± 1 °C, but marked degranulation was observed in saline-injected fish warmed to 20 ± 1 °C. There appeared to be a reduction of gonadotrope nuclear size in some dexamethasone-treated fish. It is suggested that dexamethasone inhibited ovulation in goldfish by suppressing gonadotropin secretion. Action by way of suppression of corticosteriodogenesis, for which there is good histological evidence, is also discussed, as well as the possibility of direct ovarian action.
Ultrastructural observations on the epimastigote stages of Trypanosoma avium in Simulium rugglesi
Authors: Desser Sherwin S.
Published: August 2008

Epimastigotes of variable size, shape, and density were observed adjacent to the cuticular lining of the hindgut and rectum of Simulium rugglesi that had fed 5 days previously on Trypanosoma avium infected ducks. The parasites were aligned with their flagellar ends towards the cuticle with which they formed zonal hemidesmosomes. Cytoplasmic components of the epimastigotes included free ribosomes, a well-developed anteriorly and posteriorly directed, branched mitochondrial tube with associated kinetoplast, two types of lipid inclusions, homogeneous electron-dense vesicles, and lysosomelike bodies. Dividing epimastigotes were numerous and often possessed two kinetoplasts and flagella, and four basal bodies. Intranuclear spindle tubules were observed in some dividing nuclei, but were unfortunately poorly preserved.
The influence of vasopressin on the passage of tritiated water through the isolated amniotic membrane and other tissues from the fetal guinea pig
Authors: Holt W. F. , Perks A. M.
Published: August 2008

Amniotic membranes from fetal guinea pigs (0.62–1.00 of term), were kept in a continuous-flow perfusion cell. Vasopressin (50–500 mU/ml; fetal surface) increased the unidirectional maternal–fetal flux of 3H2O by up to 12.3 ± 1.5%. The corresponding reverse flux increased only 1.6%. The responses in the maternal–fetal direction showed a linear relationship with the log dose of vasopressin. Over the same period (35 min), there was a 13.6 ± 6.3% increase in the maternal–fetal flux of 22Na+. Therefore, vasopressin may influence water movement by an effect on ions, such as Na+ or Cl−.Isolated midterm fetal skin showed closely similar effects; vasopressin (500–1000 mU/ml; outer surface) increased the amniotic–fetal flux of 3H2O by up to 30.4 ± 13.7%. The late-term fetal bladder responded to vasopressin (100 mU/ml; outer, serosal surface), by increasing the flux of 3H2O from lumen to fetus by 49.4 ± 17.8%; one bladder showed a transient rise close to 85%.The sensitivities of the skin and amnion were similar, but the bladder was about 12 times more sensitive to vasopressin. The possibility that vasopressin influences an extraplacental route for the supply of water to the fetus, through the amnion, skin, and bladder, is suggested.
The influence of food on developmental characteristics of the gypsy moth, Lymantria dispar (L.)
Authors: Barbosa Pedro , Capinera John L.
Published: August 2008

The host species consumed by larval gypsy moths have significant influences on their development. Feeding on red maple, red oak, synthetic food, and a diet of both oak and maple results in differences in mean frass production, pupal weights, and development times. Larvae feeding on the preferred food type, oak, consumed more food and produced heavier pupae than those that fed on nonpreferred maple. Development in oak-fed female larvae is significantly faster than in maple-fed female larvae. A relatively consistent proportion of extra-instar larvae of both sexes were found regardless of the food they feed upon. The implications of food type on numerical change in gypsy moth populations is discussed.
Anatomical and behavioural specialisations of shrews in relation to their diet
Authors: Pernetta J. C.
Published: August 2008

The gross anatomies of the heads of Crocidura suaveolens, Sorex araneus and Sorex minutus were examined and found to be similar in all three species. The presence of Eimers's organs and sensory vibrissae on the snout of S. minutus is demonstrated and their structure is shown to be similar to that of the European mole. The role of the various senses in prey detection and capture by shrews is discussed in the light of behavioural experimentation. It is suggested that the specialisations in anatomy, histology, behaviour, and ecology of shrews represent a major advance on the 'primitive' mammalian condition.
Respiratory development in Arctic char Salvelinus alpinus under conditions of normoxia and chronic hypoxia
Authors: McDonald D. G. , McMahon B. R.
Published: August 2008

Changes in surface morphology of the gills, ventilation rate, and heart rate were examined in Arctic char larvae exposed to normoxia (pO2 = 121 ± 6 (SE) mmHg) or chronic hypoxia (pO2 = 33 ± 3.5 mmHg) for 47 days after hatching. A modified weighted-averages technique was developed to measure aspects of gill morphology.Early development of the gills was characterized by rapid increases in filament size and number, and the emergence and proliferation of secondary lamellae. Variations in the dimensions of the gills, as noted in adult fish, were particularly evident in the larval fish.Hypoxia caused increases in both ventilation rate and heart rate. Prolonged exposure led to a retardation of gill growth, particularly the proliferation of secondary lamellae. However, growth of individual lamellae was stimulated between 38 and 47 days.
Biting flies of the eastern Maritime Provinces of Canada. I. Tabanidae
Authors: Lewis David J. , Bennett Gordon F.
Published: August 2008

Fifty-seven species of Tabanidae are recorded from maritime Canada. Thirty-one species have been collected during the period 1973–1976 in the Maritime Provinces, particularly in the Nova Scotia–New Brunswick border region. Larval and pupal habitats were not determined. Feeding habits of 20 species of tabanids were determined; 15 species were collected feeding on man, and 9 species feeding on cattle. Chrysops mitis was the most abundant deer fly and accounted for 14.5% of the tabanid population, 37.1% of the deer flies collected, and 52.6% of the deer flies feeding on man. Hybomitra epistates was the most abundant tabanid; it comprised 19.7% of the tabanids collected and 32.6% of the Hybomitra population. Hybomitra frontalis was the most abundant horse fly feeding on man, and comprised 74.2% of this group. Chrysops frigidus accounted for 42.9% of the deer flies feeding on cattle, while H. typhus Form A accounted for 50% of the horse flies feeding on cattle. Hybomitra illota was the most abundant tabanid collected in tabanid traps. Generally, species of Chrysops were more annoying to man while species of Hybomitra were more of a pest of cattle. Specimens of Tabanus were uncommon.
Asymmetry in hormone biosynthesis by insect endocrine glands
Authors: Tobe Stephen S.
Published: August 2008

The corpora allata (CA) of the desert locust Schistocerca gregaria are paired endocrine glands known to synthesize juvenile hormone (JH). The ability of individual members of the pair to synthesize JH has been examined between days 7 and 14 of adult life. Left and right glands in an individual animal can make different quantities of JH (up to 1000: 1), indicating that it cannot be assumed that endocrine glands in any given animal are of equal endocrinological activity. This asymmetry in endocrine function appears to be randomly distributed and thus the relative activity of members of the pair cannot be predicted. The asymmetry does not appear to be related to either the total quantity of JH synthesized or to the age of the animals. It is significant that no matter which member of the pair is more active, the absolute quantity of hormone synthesized by the CA of different animals of the same age is similar. The factors which regulate the endocrine asymmetry are not known but feedback loops between the brain and CA are implied. The functional significance of asymmetry may be related to a cyclical alternation in synthesis of JH by the members of the pair.
The fine structure of the leucocytes of the holothurian, Cucumaria miniata
Authors: Fontaine A. R. , Lambert Philip
Published: August 2008

The fine structure of amoebocytes, lymphocytes, and morula cells is described and related to their functions. Three morphological phases (bladder, transitional, and filiform) of the amoebocyte are distinguished. Their surface protrusions and activities are based on microtubule and microfilament systems and the transitional-filiform phases are functionally involved in coelomocyte aggregation. The bladder phase is phagocytic; bladder formation and activities are also microfilament based. Morula cells contain spherules composed of acid mucopolysaccharide and protein. Dilated rough endoplasmic reticulum (ER) cisternae apparently synthesize spherule material which is added by accretion. Lymphocytes have little cytoplasm and relatively few organelles, except for abundant rough ER and free ribosomes. Lymphocytes are probably stem cells for amoebocytes and morulas. These cells are compared with the leucocytes of other echinoderms.
The use of time by sympatric water snakes
Authors: Mushinsky Henry R. , Hebrard James J.
Published: August 2008

Daily and seasonal activity of four sympatric species of Natricine water snakes was studied in southern Louisiana. Daily patterns were monitored nearly continuously from May to October 1975, under natural conditions. Nerodia (Natrix) cyclopion and N. fasciata were mostly diurnally active but N. fasciata became nocturnal in September. Nerodia rhombifera was consistently nocturnal as was Regina grahamii for the months of July, August, and September. Concurrent field studies indicated Regina grahamii was at peak abundance in the study area in March, long before the other species reached their maximum. Nerodia fasciata was the only species to shift its activity from a diurnal to nocturnal pattern and the only species to have a slightly bimodal seasonal abundance. Partitioning of the time resource appears to be an important factor in the coexistence of Nerodia cyclopion and N. rhombifera. They are both piscivorous predators, both are abundant during the warm summer months, and both share similar micro-habitat preferences. Their asynchronous periods of peak activity would serve to reduce competitive interactions.
A field study of homing and orientation to the home site in Ulvaria subbifurcata (Pisces: Stichaeidae)
Authors: Green John M. , Fisher Robert
Published: August 2008

The movements, homing behavior, and initial orientation to the capture site were investigated in Ulvaria subbifurcata using an underwater habitat and scuba. Field experiments showed that this benthic species restricts its activity to a small home range, less than 3 m2, is capable of returning to that home area after being displaced at least 270 m, and can orient in the direction of the home site after displacements of at least 30 m. The conditions under which the orientation experiments were conducted indicate that visual cues are not necessary for the orientational response.
Digestive processes of haematophagous insects. XIII. Evidence for the digestive function of midgut proteinases of Glossina morsitans morsitans Westwood (Diptera: Glossinidae)
Authors: Gooding R. H.
Published: August 2008

Trypsin (EC 3.4.21.4), proteinase VI, proteinase VII, aminopeptidase (EC 3.4.11.1), carboxypeptidase A (EC 3.4.12.2), and carboxypeptidase B (EC 3.4.11.3) occur in the posterior section of the midgut of unfed male and female Glossina morsitans morsitans Westwood, and their activities rise after a blood meal. Only traces of these enzymes occur in the anterior section of the midgut. Elution profiles of proteins during Sephadex gel filtration of the anterior midgut at various times after feeding, and the low ratio of free amino acids to protein in the lumen of the anterior section of the midgut indicate that no significant hydrolysis of protein takes place there. Results of Sephadex® gel filtration of material from the posterior section of the midgut indicate that proteins are rapidly converted to peptides and free amino acids, which occur in high concentration there. The results are interpreted as indicating that digestion of proteins takes place only in the posterior section of the midgut, and that all six proteolytic enzymes have a digestive function.
The demography of Synaptomys cooperi populations in eastern Kansas
Authors: Gaines Michael S. , Rose Robert K. , McClenaghan Jr. Leroy R.
Published: August 2008

Three populations of the southern bog lemming, Synaptomys cooperi, were livetrapped from November 1970 through July 1973 in eastern Kansas to determine whether populations of this microtine species undergo multiannual population cycles. Two of the populations (grids B and D) had such cycles, while one (grid A) exhibited an annual fluctuation in density. The intensity of breeding was generally higher in the summer than in the winter breeding seasons. Grids B and D had a higher percentage of males in breeding condition during two summer breeding seasons compared with grid A. Survival of the trappable adult population was usually higher in the winter than in the summer breeding seasons. Early juvenile survival paralleled changes in survival of the adults but average juvenile survival on grid A was lower than on grids B and D during the summer breeding season. A multiple regression analysis indicated that early juvenile survival is the best predictor of rate of population growth. High body weights in spring were associated with high population densities on grids B and D. Mean body weights of all three populations were higher in the summer than in the winter breeding seasons. Possible mechanisms for the noncyclicity on grid A are discussed.
The role of breeding behavior and habitat preferences on the reproductive isolation of three allopatric populations of ninespine stickleback, Pungitius pungitius
Authors: Foster John R.
Published: August 2008

Earlier studies have shown differences in morphology and reproductive behavior of Mississippi, Bering, and European populations of ninespine stickleback (Pungitius pungitius). In this study, assortative mating was examined experimentally to determine the role of habitat preference and breeding behavior as possible isolating mechanisms. Choice tests in naturalistic and uniform environments showed positive assortative mating in all but one pairing. One-hour latency tests gave similar results, while in the 24-h latency tests, interpopulation mating became prevalent. Although nesting habitat selection differences were found, courtship breakoff appeared to be a more important isolating mechanism. Failure to induce females to court was probably due to differences in male color, size, body proportions, and zigzag display. Failure to lead the female to the nest was probably related to differences in color and leading behavior, while failure to induce the female to enter the nest was probably related to differences in nesting substrate, nest location, and size, type, and number of entrances. The results of this study demonstrate that reproductive divergence among the three populations makes intrapopulation mating more likely than interpopulation mating.
Effect of premature transfer to sea water on growth and morphology of the pituitary, thyroid, pancreas, and interrenal in juvenile coho salmon (Oncorhynchus kisutch)
Authors: Clarke W. Craig , Nagahama Yoshitaka
Published: August 2008

Stunted coho salmon exhibited prominent parr marks and had a lower coefficient of condition than normal coho in sea water. Light and electron microscopic observations of the pituitary gland indicated that the prolactin cells of the runts were less active than in normal seawater coho whereas the growth hormone cells were more numerous and filled with secretory granules. The thyroid and endocrine pancreas had regressed while the interrenal cells showed little difference from the controls.After return to fresh water for 4 months, the runts acquired a silvery appearance and their condition factor increased to the normal level. In fresh water, the pituitary regained a more normal appearance. The prolactin cells became hypertrophied while the growth hormone cells contained less secretory material.
Quantitative composition of the fertilized ovum and constituent parts in the Atlantic salmon Salmo salar L.
Authors: Hamor T. , Garside E. T.
Published: August 2008

Quantitative analysis of fertilized, water-hardened Atlantic salmon ova was performed principally by gravimetry and thin-layer chromatography. Dry weight was 36% of mean total weight (138 mg). Dry weight of yolk was 39% of mean weight (104 mg), and dry weight of zone radiata was 8% of mean weight (5 mg). Eight phospholipids, lysophosphatidyl choline, L-α-phosphatidyl choline, sphingomyelin, phosphatidylethanolamine, phosphatidyl choline, phosphatidyl-L-serine, o-phosphoethanolamine, and lysophosphatidylethanolamine, comprised 23% of the dry yolk. Nonpolar lipids formed 24% of the dry yolk. Less than 1% of the dry ovum weight was carbohydrate. Almost all carbohydrate was concentrated in the zona radiata (60% of dry weight), apparently as mucopolysaccharides. Other components included minute quantities of ash, non-protein nitrogen, cholesterol, RNA and DNA. Composition of perivitelline fluid was inferred from unaccounted remainders of the various components.
Metabolic clearance and production rates of testosterone at different times of the year in male caribou and reindeer
Authors: Whitehead Philip E. , West Nels O.
Published: August 2008

The metabolic clearance rate (MCR) of testosterone at different times of the year in male caribou and reindeer was determined by calculating the volume of plasma cleared of a single injection of tritiated testosterone per unit time. The MCR was then used to estimate the daily production rate, from the arithmetic product of the clearance rate and the plasma testosterone concentration before the injection. During midrut, plasma testosterone levels of 13–22 ng/ml and MCRs of 601–782 ℓ/day gave production rates of 10–13 mg/day. During the nonreproductive period, low plasma testosterone levels (0.4–0.6 ng/ml) and higher clearance rates (1142–2535 ℓ/day) gave production rates of 0.6–1.4 mg/day. The unexpectedly low MCRs that were obtained during the rut were associated with lower volumes of distribution (v1 and v1 + v2), which suggests that the binding capacity of the plasma is higher at this lime. Since only the unbound fraction is available for entry into the cells, information about the binding capacity of the plasma is required before the MCR can be evaluated in terms of the uptake and metabolism of testosterone by the tissues.
Infectivity of Trypanosoma murmanensis to leeches (Johanssonia sp.)
Authors: Khan R. A.
Published: August 2008

Experiments were designed to test the infectivity of trypomastigotes of Trypanosoma murmanensis to leeches at intervals after metatrypomastigotes had initiated infections in marine fish. Infectivity was determined by the presence of developmental stages in recently emerged leeches (Johanssonia sp.) that had fed on experimentally infected fish. A total of 1235 leeches were used in this study. The results indicate that the three morphotypes can initiate infections in leeches. Moreover, some trypanosomes are infective at least 24 h after transmission (16 (67%) leeches became infected). Few leeches acquired infections after feeding on infected winter flounder (Pseudopleuronectes americanus) between 2 and 12 days and on a cod (Gadus morhua) 4–5 days, but all those which fed 7 through 93 day s on five species of marine teleosts became infected. Some of the leeches transmitted infections to uninfected cod. It is believed that the leeches which harboured no developmental stages might not have ingested trypanosomes.
Evidence for neurosecretory cells in the cestode Hymenolepis microstoma
Authors: Webb Rodney A.
Published: August 2008

Electron microscopy of the neck region of the cestode Hymenolepis microstoma revealed neurons with the characteristics of neurosecretory cells. The neurosecretory cells differ from the other nerve cells by the presence of α-glycogen in the neurites, by their content of large electron-dense vesicles, and by the ultrastructural manifestation of neurosecretory release sites. The dense neurosecretory vesicles, 915 ± 151 Å to 1040 ± 201 Å (1 Å = 0.1 nm) in diameter, are formed at the Golgi complexes and accumulate in the axon varicosities or boutons, the synaptoid release sites. Omega profiles, electron-dense focal sites, neurosecretory vesicles with contents of variable electron density, and small electron-lucent vesicles set in a fine granular matrix are observed at the release sites. The neurosecretory material is released from the electron-dense vesicles into the intercellular spaces. Neurosecretory synapses are described.