bluuebunny/crossref_metadata_2025 huggingface dataset:
Blood ionic and acid–base status in rainbow trout (Salmo gairdneri) following rapid transfer from freshwater to seawater: effect of pseudobranch denervation
Authors: Perry S. F. , Heming T. A.
Published: April 2009

Effect of pseudobranch denervation on the ability of Salmo gairdneri to regulate blood ionic and acid–base balance was investigated in freshwater and following transfer to seawater. Denervation of the pseudobranch did not affect internal ionic or acid–base equilibrium in freshwater. Plasma [Cl−], [Na+], pH, total [Formula: see text], and partial pressure of [Formula: see text] of trout were affected by transfer from freshwater to seawater, and by transfer back to freshwater. These ionic and acid–base responses were not affected by denervation of the pseudobranch. It is concluded that alone, the pseudobranch plays little or no role in ionic and osmotic regulation during transfer between freshwater and seawater.
Effects of food quality on the growth of three Hydropsyche species (Trichoptera: Hydropsychidae)
Authors: Fuller Randall L. , Mackay Rosemary J.
Published: April 2009

Growth responses of third, fourth, and fifth instars of Hydropsyche betteni, H. slossonae, and H. sparna were observed while on diets restricted to leaf or fecal detritus, diatoms, or animal material. Larval weight increases were 7.0 times higher on an animal material diet and 4.6 times higher on a diatom diet than on either a leaf or fecal detritus diet. The relative percent contribution of each food type to larval growth in the field suggested detritus was of little importance to later instars; however earlier instars may depend more on detritus. Diatoms showed the greatest contribution to larval growth for all species and instars. Animal material varied in importance depending on season, species, and instar. These results suggest autotrophy may be a very significant factor in energy flow within stream ecosystems, especially in terms of filter-feeder diversity and abundance. No instar appeared to be better able to utilize one type of food over another. However, H. sparna larvae consistently grew faster than other species on all food types; its widespread distribution may be related to its ability to more efficiently utilize a variety of food resources.
A comparative study of transacylation in three insect species
Authors: Barlow J. S. , Jones D.
Published: April 2009

The acyl specificity of microsomal glycerophosphate transacylase from the wax moth, Galleria mellonella, and the blowfly, Lucilia sericata, could not explain the fatty acid composition of these two insects. Differences in acyl specificity between the two species did, however, reflect the differences in fatty acid composition of the species.Variable acyl specificity between replicate preparations of L. sericata microsomal glycerophosphate transacylase suggests there are specific sites on the enzyme for each fatty acid and that the number of sites is variable.In the hymenopterous parasitoid Exeristes roborator, glycerophosphate transacylase activity was not detected in the cytosolic, mitochondrial, or microsomal fractions. Microsomal preparations incorporated palmitate from labelled palmitoyl-S-CoA into the diglyceride and triglyceride fractions indicating an active monoglyceride pathway. These results suggest the parasitoid incorporates glycerides directly from the host. The absence of the glycerophosphate pathway partially explains the fatty acid mimicry which is a feature of E. roborator lipid metabolism.
Responses of a deer mouse population to a forest herbicide application: reproduction, growth, and survival
Authors: Sullivan Thomas P. , Sullivan Druscilla S.
Published: April 2009

This study was designed to monitor some of the demographic responses of a deer mouse population to a forest application of Roundup® herbicide. Populations of Peromyscus maniculatus were livetrapped from July 1978 to November 1980 on a control area and in a herbicide-treated 20-year-old Douglas-fir plantation at Maple Ridge, British Columbia. The herbicide had no apparent adverse effects on reproduction, growth, or survival of deer mice 1 year after treatment. Inconsistencies in growth rates and juvenile survival between control and experimental deer mice in 1980 could be due to the herbicide or demographic factors. Field dose applications of this herbicide should not have a direct effect on the dynamics of deer mouse populations.
Avian Haemoproteidae. 15. The haemoproteids of the avian family Zosteropidae
Authors: Bennett Gordon F. , Peirce Michael A.
Published: April 2009

The haemoproteids of the avian family Zosteropidae are reviewed. Haemoproteus zosteropis Chakravarty and Kar, 1945 is redescribed; H. johnstoni Laird &Laird, 1959 is declared a synonym of H. zosteropis and Haemoproteus killangoi n.sp. is described from Zosterops senegalensis. Haemoproteid records from the Zosteropidae are summarized.
Activities of oxidative and glycolytic enzymes in fetal heart, lung, and brain in the Weddell seal
Authors: Murphy B. J. , Hochachka P. W.
Published: April 2009

The oxidative and glycolytic capacities of brain, heart, and lung in near-term Weddell seal fetuses were estimated from the maximal activities of four mitochondrial marker enzymes and four glycolytic enzymes. The catalyic potentials for both groups of enzymes were similar to adult levels in all three organs examined. It was concluded that the critical metabolic functions performed by these three central organs during diving are already fully developed in the fetal seal. This early development of adult-type metabolic machinery did not appear to be a preparatory step for later extrauterine function, but rather appeared to be necessary for times of normal maternal diving, when fetal metabolic responses mimic those of the mother.
Identification of Diplostomum spp. from the eyes of lake whitefish, Coregonus clupeaformis (Mitchell), based on experimental infection of herring gull chicks, Larus argentatus Pontoppidan
Authors: Dick T. A. , Rosen R.
Published: April 2009

Based on the morphology of adults recovered from experimental infection of gulls, the metacercariae from the eyes of lake whitefish were identified as Diplostomum spathaceum indistinctum and Diplostomum baeri bucculentum. The two species inhabit different sites in both fish and bird hosts:D. s. indistinctum in the lens and D. b. bucculentum in the vitreous humour and retina of lake whitefish and D. s. indistinctum in the anterior 20% and D. b. bucculentum in the anterior 60% of the intestine of gulls. Both species can be distinguished by differences in body size, ratios of forebody to hindbody, and position of ovary, and can be separated in mixed infections in gulls.
Pseudomacrostomism in coral reef fish
Authors: Blake R. W.
Published: April 2009

Distinctive colour bands which give the false impression of large mouth size are common among the Balistidae, Labridae, and Scaridae. A preliminary interpretation of pseudomacrostomism function is given.
Coordinated behavior of killer whales, Orcinus orca, hunting a crabeater seal, Lobodon carcinophagus
Authors: Smith Thomas G. , Siniff Donald B. , Reichle Richard , Stone Sheridan
Published: April 2009

A pod of seven killer whales (Orcinus orca) was seen to attack a lone crabeater seal (Lobodon carcinophagus) which was lying on an ice floe. The whale located the seal, moved away from the floating ice, then swam as a group close to the floe. This caused a wave which tipped up the ice floe and broke over it, causing the seal to be thrown into the water. The whales swam immediately to the vicinity of where the seal disappeared but it was not possible to ascertain if a kill was made.
Eye lens weight and body size as criteria of age in beaver (Castor canadensis)
Authors: Malcolm Jay R. , Brooks. Ronald J.
Published: April 2009

Ages of 114 wild-caught beaver (Castor canadensis) had been estimated by cementum layer technique. Relationships between total lens dry weight, body weight, axillary girth, and these estimated ages are described. Total lens dry weight was better than either body weight or axillary girth as a predictor of age. However, none of these criteria, whether used alone or in combination in a multiple regression model, allowed animals more than 1 year old to be placed into year classes with confidence. Linear regression of log10 body weight on log10 axillary girth yielded a slope of 2.0. The discrepancy between this value and slopes obtained for other species may reflect a functional difference in shape and growth of beaver.
Nectonema (Nematomorpha: Nectonematoidea) a parasite of decapod Crustacea in the Bay of Fundy
Authors: Leslie H. A. , Campbell A. , Daborn G. R.
Published: April 2009

Juvenile stages of the marine nematomorph genus Nectonema were found in the rock crab, Cancer irroratus, jonah crab, C. borealis, hermit crab, Pagurus acadianus, and the shrimps, Pandalus montagui and P. borealis, in the Bay of Fundy. No effects on the internal organs of most parasitized hosts could be detected although some male rock crabs had atrophied gonads suggesting parasitic castration by Nectonema. In the area of highest parasite incidence 48% of the rock crabs and 11.6% of the hermit crabs sampled were parasitized with Nectonema. Taxonomic work with the genus Nectonema is needed.
Correlation of laying and hatching sequences in clutches of the lesser snow goose (Anser caerulescens caerulescens)
Authors: Cargill Susan M. , Cooke Fred
Published: April 2009

Lesser snow goose nests were monitored daily during laying and hatching. Within each clutch, eggs were numbered serially as they were laid. Subsequently, the order of hatching within clutches was determined. In nests where three to five eggs hatched, the sequence of hatching was strongly dependent on the laying sequence. This implies that some development of embryos occurred throughout the laying period, so that the young varied in the stage of development attained prior to the onset of incubation. This inequality persisted until hatching, resulting in the observed asynchrony. Evidence from other workers suggests that development during laying occurs in some other waterfowl species, but does not necessarily result in asynchronous hatching or correlation of hatching and laying sequences.
Renal perfusion pressure and renin secretion in the rainbow trout, Salmo gairdneri
Authors: Bailey J. R. , Randall D. J.
Published: April 2009

In the trout, Salmo gairdneri, a significant correlation between the amount of blood loss and plasma renin activity was established. This increase in plasma renin activity could be due to stimulation of an intrarenal receptor, thus an isolated nonfiltering perfused kidney preparation was developed to test this hypothesis. It was found that a decrease in renal perfusion pressure resulted in an increase in renin release (as measured by perfusate renin activity) but an increase in renal perfusion pressure had no effect on renin release. The increase in renin secretion in response to a decreased renal perfusion pressure was not affected by sympathetic nervous system blocking agents, whereas angiotensin II will apparently inhibit renin secretion in vitro. It was concluded that a baroreceptor response, similar to that found in mammals, is found in fishes and a model mechanism for renin secretion in fishes is proposed.
Generic revision of Criconematidae (Nematoda): Nothocriconema and related genera with proposals for Nothocriconemella n.gen. and Paracriconema n.gen.
Authors: Ebsary B. A.
Published: April 2009

The genera Nothocriconema, Lobocriconema, Neolobocriconema, and Merocriconema are revised, diagnosed, and illustrated. Two proposed new genera, Nothocriconemella and Paracriconema, are described. Nothocriconemella differs from Nothocriconema by having the first head annule narrower and not strongly separated from the second, retrorse body annules 4–6 μm thick, and smooth-scaled juveniles. Paracriconema differs from Nothocriconema by having a rounded conical tail of four to eight annules, VL/VB = 1(0.7–1.1), and smooth-scaled juveniles. Nothocriconema arcanum is synonymized with Nothocriconemella pacifica and Nothocriconema mukovum with Nothocriconemella mutabilis. Nothocriconema acriculum, N. calvum, N. coorgi, N. degrissei, N. demani, N. grassator, N. kovacsi, N. longulum, N. macilentum, N. mutabile, N. orientale, N. pacificum, N. paraguayense, N. pasticum, N. permistum, N. psammophilum, and N. sphagni are transferred to Nothocriconemella, becoming new combinations. Other new combinations include Lobocriconema hlagum, Paracriconema dubium, P. duplicivestitum, P. lamellatum, P. rarum, and P. solitarium.
Cycle de développement, croissance, effectifs, biomasse et production de Bithynia tentaculata L. (Gastropoda : Prosobranchia) dans le Saint-Laurent (Québec)
Authors: Vincent B. , Vaillancourt G. , Harvey M.
Published: April 2009

The life cycle of Bythinia tentaculata has been studied over a period of 2 years in five localities of the freshwater estuary of the St. Lawrence River. Sexual maturity is attained after 2 years and the species is iteroparous; this might prove to be a particularly advantageous reproductive strategy in this river. The main phases of individual growth are related to age and thermal variations of the water and they occur during the months of May, June, and July of the first 2 years. Eggs are laid once a year and growth stops during winter for about 6 months. These results on the life cycle and growth of B. tentaculata, particularly in the fluvial section of the St. Lawrence River, are more similar to those obtained in Europe than to those obtained elsewhere in North America. Numbers, biomass, and production are markedly higher here than the values found by other investigators on the same species.[Journal translation]
Field and laboratory activity patterns in the burrowing wolf spider Geolycosa domifex (Hancock)
Authors: McQueen D. J. , Culik B.
Published: April 2009

The major objectives of this study were to determine the amount of time that the burrowing wolf spider Geolycosa domifex spends engaged in various types of activity in both the laboratory and field, and to test the hypothesis that these animals exhibit diel activity patterns. Seven types of activity were common. In the field, activity patterns were monitored using photocells, and in the laboratory, closed-circuit television was used. In both the field and laboratory, no statistically significant diel patterns were observed. Similar results were obtained from a single individual which was intensively studied during six time periods monitored over a 1-month period. The conclusion is that diel light patterns, sudden changes in light intensity, or endogenous rhythms do not influence activity patterns in G. domifex. The average time spent in each type of activity was (a) 3.2 min/h resting at the burrow mouth, (b) 21.3 min/h resting in the top 4 cm of the burrow, (c) 30.5 min/h below 5 cm, (d) 2.2 min/h outside the burrow, and (e) 2.8 min/h active in the top 4 cm of the burrow.
Oxygen uptake in the lingcod, Ophiodon elongatus, during progressive hypoxia
Authors: Farrell A. P. , Daxboeck C.
Published: April 2009

Oxygen uptake [Formula: see text] in the resting lingcod was 22.8 ± 0.6 mL O2∙h−1∙kg−1. During progressive environmental hypoxia lingcod maintained or elevated their [Formula: see text] provided the water oxygen tension was greater than 45 mmHg. Increased [Formula: see text] (up to fourfold) during moderate hypoxia was associated with activity.
Ecology of the wolverine in northwestern Montana
Authors: Hornocker Maurice G. , Hash Howard S.
Published: April 2009

A population of wolverines was studied in northwestern Montana for 5 years (1972–1977). Twenty-four wolverines were captured in live traps, individually marked, and released. Ten individuals were recaptured 74 times. Twenty wolverines were fitted with radio transmitters and 576 relocations were made over a 4-year period. A minimum population size of 20 was estimated for the 1300-km2 area, or one wolverine per 65 km2. The population was believed stable. This stability was maintained by mortality and dispersal. Wolverines utilized relatively large areas. The size and shape of ranges were not affected by rivers, reservoirs, highways, or major mountain ranges. The average yearly range of male and female wolverines was 422 and 388 km2, respectively. Wolverines exhibited fidelity to a given area, but several individuals of both sexes made frequent long movements to other areas. In all instances wolverines returned to the same area. Ranges overlapped between individuals of the same and opposite sex. Territorial defense was essentially nonexisent. Wolverines scent marked to maintain spacing in time but not area. Wolverines appeared to select Abies cover types throughout the year; this selection was strongest in summer. In Montana, wilderness habitat coupled with more restrictive harvest regulations should provide for secure wolverine populations in the foreseeable future.
A quantitative morphological study of the pineal organ in the goldfish, Carassius auratus
Authors: McNulty John A.
Published: April 2009

Stereological techniques applied to a light and electron microscopic study of the pineal organ of the goldfish indicated that photoreceptor and supportive cells were comparable in their number and cell volume and that approximately 500 nerve cells were present in the pineal end vesicle. There were approximately 310 nerve fibers descending the distal part of the pineal tract. Quantitative analysis of organelles in photoreceptor cells revealed that the endoplasmic reticulum and Golgi bodies, in the vicinity of which were situated both clear and dense-cored vesicles, formed a substantial part of the cytoplasmic volume. Other new observations reported for this species include a close association between mitochondria and parts of the smooth endoplasmic reticulum, a characteristic feature of photoreceptor cells, and the presence of subsurface cisternae formed from profiles of endoplasmic reticulum. Moreover, specialized contacts were found between both photoreceptor and supportive cells. Some of these ultrastructural features are similar to those reported in the secretory pinealocytes of mammals. These findings suggest that (1) the pineal organ in this species has a high degree of photosensitivity as evidenced by the large number of photoreceptor cells related to each nerve cell, and (2) photoreceptor cells are metabolically active possibly having functions other than photoreception.
Twilight and day length affects the seasonality of entrainment and endogenous circadian rhythms in a fish, Couesius plumbeus
Authors: Kavaliers Martin , Ross Donald M.
Published: April 2009

Twilight and day-length portions of the light-dark cycle determine the seasonal course of (i) the phase relationship (ψ) between activity and the daily environmental light–dark cycle, (ii) the duration of activity (α), and (iii) the circadian period (τ) under constant darkness of the lake chub (Couesius plumbeus). With fish held under seasonally appropriate light–dark cycles with twilight (LD + t), the onset of diurnal activity occurred during dawn and its timing (ψonset) followed a bimodal annual pattern that was correlated with seasonal changes in the duration and physical characteristics of twilight. The end of activity occurred during dusk (ψoffset) and followed a unimodal annual pattern that was determined by day length. α followed a sigmoidal annual pattern under LD + t. The circadian period underwent significant seasonal changes with maximum and minimum τ values occurring during summer and winter, respectively. Fish that were entrained to rectangular light–dark cycles that excluded twilights (LD) failed to show any seasonal changes in ψ and τ and the sigmoidal relation between α and day length was absent.
Studies on gametogenesis in Gyrinicola batrachiensis (Walton, 1929) (Oxyuroidea: Nematoda)
Authors: Adamson M. L.
Published: April 2009

Cytological aspects of gametogenesis were investigated in populations of Gyrinicola batrachiensis (Oxyuroidea; Nematoda) from various anuran hosts. Populations parasitizing Rana clamitans reproduced by haplodiploidy. Females had eight chromosomes and oocytes underwent normal meiosis. Fertilized eggs containing eight chromosomes and unfertilized eggs containing four chromosomes were observed in the uterus of females. Males had four chromosomes and spermatozoa were produced mitotically. This is the first report of haplodiploidy in a nematode. Populations of G. batrachiensis parasitizing tadpoles in ponds where R. clamitans was absent reproduced by apomictic thelytoky. Females had six, seven, or eight chromosomes depending on the strain. There was no chromosome pairing nor bivalent formation. A diploid number of univalents divided to form a single polar body and a pronucleus. Apomictic strains of G. batrachiensis probably arose when mutations supressed the first meiotic division in haplodiploid strains. Apomictic females do not need to locate a mate and can begin to reproduce as soon as they are mature. Gyrinicola batrachiensis occurs only in the tadpole stage and apomictic strains are most successful in anurans in which the tadpole stage is brief.
Experimental studies on acarine predator–prey interactions: the numerical response of immature and adult predators (Acarina: Phytoseiidae)
Authors: Eveleigh Eldon S. , Chant D. A.
Published: April 2009

The numerical responses of two species of phytoseiid mites, Phytoseiulus persimilis and Amblyseius degenerans, were studied in the laboratory. Developmental times and survival rates were examined in the immature instars and oviposition rates in adult females. Prey requirements for development, survival, and oviposition were lower with P. persimilis than A. degenerans due to the nature of their respective feeding and searching behaviour. The fecundity of P. persimilis increased linearly with increasing numbers of prey killed, whereas that of A. degenerans increased curvilinearly. Experiments on the effects of the feeding history of adult females on their fecundity showed that their response depended not only on their most recent nutritional history but also on prey conditions experienced early in their adult lives. The ability of the females to respond to an increase in prey density may be enhanced or reduced depending on the prey conditions experienced. The manner in which the requirements for prey, and the feeding and searching behaviour of the predators, influenced their responses is discussed.
The feeding and searching behaviour of two species of phytoseiid mites, Phytoseiulus persimilis Athias-Henriot and Amblyseius degenerans (Berlese), at different prey densities (Acarina: Phytoseiidae)
Authors: Eveleigh Eldon S. , Chant D. A.
Published: April 2009

Detailed observations were made on various components of the predatory behaviour of each instar of two species of predacious phytoseiid mites, Phytoseiulus persimilis and Amblyseius degenerans, in the laboratory. These observations revealed that many aspects of the feeding and searching behaviour of these predators are dependent on the prey density to which they are exposed. Differences between the two species are described and it is concluded that P. persimilis has a greater ability to modify its behaviour in relation to prey conditions than A. degenerans. The results explain why P. persimilis has a lower capacity for prey and lower prey requirements for survival, development, and reproduction than A. degenerans, and also the nature of the functional and numerical responses to prey density of the two species.
Occurrence and distribution of littoral Chydoridae (Crustacea, Cladocera) in Ontario, Canada, and taxonomic notes on some species
Authors: Hann Brenda J.
Published: April 2009

Of the 39 species of littoral Chydoridae reported from Ontario, 7 are new for the province, and 2 are new to Canada. Higher species numbers per locality were found in the soft-water lakes of the Precambrian Shield areas as compared with the harder-water lakes of southwestern Ontario. Several species exhibited distinct differences from the original descriptions based on European material, and critical taxonomic features of these species are described and discussed.
Phallodrilus tempestatis n.sp., a new marine tubificid (Annelida: Oligochaeta) from British Columbia
Authors: Baker H. R.
Published: April 2009

Phallodrilus tempestatis n.sp., a marine tubificid (Annelida: Oligochaeta) from intertidal habitats of British Columbia, is characterized by frequent extension of one spermathecal ampulla into IX, the broad attachment of the anterior prostate to the atria, and the form and number of penial setae. Phallodrilus tempestatis n.sp. extends the distribution of Phallodrilus to the North Pacific.
On the inhibitory effect of some steroids on spermatogenesis in adult rainbow trout (Salmo gairdneri)
Authors: Billard R. , Breton B. , Richard M.
Published: April 2009

To test the antifertility effect of various steroids, fish were fed a diet containing steroids at two stages of the reproductive cycle: during spermatogenesis (June to November, experiment A) and during spermiation (November to February, experiment B). The fish in experiment A were given testosterone (T), methyltestosterone (MT), estradiol-17β (E2), hexestrol (H), progesterone (Pg), and FGA (Fluorogestone acetate) at doses of 0.05 and (or) 0.5 mg/kg of food. In experiment B, T, MT, and E2 were given at a dose of 0.5 mg/kg of food. The fish received a daily ration amounting to 1% of their body weight. In experiment A, inhibition of testicular growth was total with 0.5 mg MT and 0.5 mg E2 and partial with 0.5 mg T/kg of food. In these groups, there was no noticeable change in plasma gonadotropin (GTH) compared with the controls, except that the GTH rise observed in the other groups in September was prevented. This suggests that steroids act directly at the level of the gonad. In experiment B, no noticeable regression of the gonad occurred after steroid treatment. A big GTH rise was seen in the E2-treated group, but this was not followed by stimulation of spermiation. The total amount of sperm (50%) and spermatozoa collected during the experiment tended to be lower in the steroid-treated fish than in the controls. Spermatozoal fertilizing ability was significantly decreased (P < 0.005) by the testosterone treatment.
Wound repair in a spider, Geolycosa pikei
Authors: Bursey Charles
Published: April 2009

Observations are presented on the wound repair process of a burrowing wolf spider, Geolycosa pikei. Awound,0.3 × 1.0 × 0.5 mm, was made in the superior lateral aspect of the abdomen and observations on tissue from the wound site were made at 2, 6, 12, 24 h, 4, 8, 16, 32, 60, 90, 120 days. The wound was plugged immediately by a hemolymph coagulum. With time, the external portion of the coagulum was reduced to a scale which bridged the hole in the exoskeleton; the internal portion of the coagulum was replaced by a fibrous mass which was gradually lost through a series of changes that eventually restored the original tissue structure.
Compass orientation of sockeye salmon fry from a complex river system
Authors: Brannon Ernest L. , Quinn Thomas P. , Lucchetti Gino L. , Ross Brian D.
Published: April 2009

Sockeye salmon (Oncorhynchus nerka) fry from the Weaver Creek – Harrison Lake population were tested to determine whether they exhibited directional orientation in the absence of water flow. The fry oriented in a generally north-northeast direction. The presence of the moon greatly enhanced the strength of the northward orientation response, and the moon may have provided the fry with guidance information. Tests with newly emerged fry indicated little or no response to a directionally altered magnetic field. Both the passage of time and exposure to Harrison River – Harrison Lake water enhanced the compass orientation response, implying that an inherited response is triggered by environmental and temporal cues.
The effects of cold temperatures and crude oil on the abundance and activity of protozoa in a garden soil
Authors: Rogerson Andrew , Berger Jacques
Published: April 2009

The abundance and number of protozoan species inhabiting garden loam soil were monitored throughout the winter of 1979–1980 in both undisturbed and crude oil polluted sites. The effect of oil contamination on protozoan colonization was investigated using autoclaved soil cores. Oil did not appear to affect seriously either the encysted or trophic protozoa. Encystment was rapid at temperatures above 0 °C, and the evidence suggests that the soil protozoan population was active for short periods on many occasions throughout the winter.
Growth and energy consumption by captive mallards
Authors: Sugden Lawson G. , Driver E. A. , Kingsley Michael C. S.
Published: April 2009

Weight change of mallards (Anas platyrhynchos) reared in indoor cages was described by a modification of Richards's growth function that was compared with Gompertz and logistic growth equations. Growth of both sexes approximated the Gompertz curve. Maximum growth rate occurred at 2.5 weeks. Intake of metabolized energy increased from a mean of 49 kcal∙bird−1∙day−1 (1 cal = 4.1868 J) in the 1st week to 262 kcal during the 5th week, and then decreased as growth slowed.
Where, when, and how male sharp-tailed grouse establish territories on arenas
Authors: Moyles D. L. J. , Boag D. A.
Published: April 2009

The behaviour of individually marked male sharp-tailed grouse (Pedioecetes phasianellus) was observed on four arenas over two successive autumn-to-spring periods to determine the fate of established birds, and where, when, and how young males established new territories on the arenas. The lekking cohort of males frequented the arenas from September to June with peak attendance in April. This cohort suffered an average loss of 56% between spring and autumn with males occupying peripheral territories disappearing in greater proportions than those on central territories; this loss is believed to represent mortality. Surviving males moved centripetally to fill any central vacancies, leaving potential territories vacant peripherally. It was only here at the edge of the arena that young males were recorded successfully establishing territories. Most (68%) were established in autumn and early winter. Males in adult plumage (assumed to be about 18 months old) were relatively more successful (13/15) in acquiring territories between September and March than birds in immature plumage (about 6 months old) (11/23). Acquisition of a territory appeared to involve the following sequence of events: repeated use of a site, low intensity display (mainly towards more peripherally located and largely nonterritorial males), establishment of mutual recognition, full display, and defence of space against all neighbours.
Neuroanatomy and control of the caudal lymphatic heart of the short-finned eel (Anguilla australis schmidtii)
Authors: Davie Peter S.
Published: April 2009

The caudal lymphatic heart of the short-finned eel is found in the most posterior segment of the tail. This organ pumps lymph from lateral, caudal, and caudal fin lymphatic vessels into the caudal vein. The anatomy of the heart was studied using light and electron microscopic techniques. Lymph heart muscle is typical of vertebrate fast-acting skeletal muscle. The muscles on each side are innervated by a spinal nerve from the penultimate vertebra. Neuromuscular junctions are of the "en plaque" type and contain spherical vesicles about 60 nm in diameter. Ablation experiments show that the lymph heart beat is neurogenic. It is suggested that action potentials from the penultimate segment of the spinal cord, which are transmitted to the lymph heart by spinal motor axons, initiate lymph heart contractions.
The effect of extra food and cover on declining populations of Microtus townsendii
Authors: Taitt Mary J. , Gipps J. H. W. , Krebs C. J. , Dundjerski Z.
Published: April 2009

Microtus townsendii populations were supplied with extra food and extra cover during a spring decline in numbers in 1979. Compared with the control population, late-winter addition of food resulted in lower rates of decline of males and females. On the area with extra cover, the rate of decline was significantly lower in males, and females actually increased in number. Breeding was earlier in the population with extra cover, and four times as many females became pregnant during the spring. This resulted in twice as many young voles entering the population in early summer. Survival was higher in both experimental populations during the spring. Females with extra food and males with extra cover had the smallest home ranges for their sex group.The experiments were repeated in summer 1979, except that cover was reduced on one grid. Demography during the summer experiments was similar in all populations. This period coincided with a botfly (Cuterebra) larva infection which reduced survival of voles in all populations.The addition of cover reduced bird predation. If this was the only effect of added cover, the demography of the covered population suggests that predation may be important in the spring decline of M. townsendii. Further, we suggest that the severity of the spring decline, particularly in female voles, may determine when the population "cycles."
Differential effect of formalin preservation on yolk and tissue of young chinook salmon (Oncorhynchus tshawytscha Walbaum)
Authors: Heming T. A. , Preston R. P.
Published: April 2009

Preservation in 5% neutral formalin for periods up to 50 days differentially increased the yolk and tissue weight of young chinook salmon (Oncorhynchus tshawytscha). Yolk gained relatively more weight than tissue. As a result, intact alevins showed a net weight gain during preservation, the magnitude of which was related to the amounts of yolk and tissue present at preservation. No single correction factor was generally applicable to compensate for weight changes in preserved alevins. On the other hand, preservation had little effect on weight of intact chinook eggs, regardless of egg composition. Presumably, increases in yolk and tissue weights of preserved eggs were masked by loss of perivitelline fluid.
A microcomputer-based measuring device for biological research
Authors: Sprules W. Gary , Holtby L. Blair , Griggs Gerald
Published: April 2009

As an inexpensive, more versatile alternative to the Coulter counter and image analyzers for the acquisition of size data in biological research, a semiautomated measuring device with associated data storage and retrieval capabilities has been developed. It can be used for measurement of such diverse characters as zooplankton body size and helmet lengths, phytoplankton size, fish scale measurements, fish egg diameters, and general taxonomic features such as body proportions and inter-setule distances. Any organism, or part thereof, which can be scaled to the device's range of approximately 1–7 cm can be quickly and accurately counted and (or) measured.
A preliminary report on a technique to analyze the activity of Entamoeba histolytica trophozoites in vitro
Authors: Smith J. M. , Meerovitch E.
Published: April 2009

A quantitative method for measuring the activity of individual amoebae in vitro is described. Trophozoites of three strains of Entamoeba histolytica, IP-106, NIH:200, and DKB, were compared and measurable differences in behaviour and activity between the three strains were observed. Although the total number of pseudopodia produced by amoebae was the same for the three strains tested, amoebae of strains IP-106 and NIH:200 moved farther during a 5-min period than did those of strain DKB. This correlates with a more tortuous track of the latter strain.
Free and bound cyclic AMP in the brain of the moth Mamestra configurata Wlk. during pupal–adult metamorphosis
Authors: Bodnaryk Robert P.
Published: April 2009

Neither free nor bound cyclic AMP in the brain of the moth Mamestra configurata changed significantly during the first few days in which neuroendocrine events responsible for initiating pupal–adult development occurred. Apparently, the level of bound cyclic AMP in the brain reflects a state of protein kinase activation that is sufficient to initiate development in pupae that have completed diapause and are exposed to temperatures above the initiation threshold. Brain cyclic AMP is not involved in the transduction of photoperiodic signals in the pupa of M. configurata, as it is in the pupa of certain silkmoths.Large increases occur in the level of free and bound cyclic AMP in the brain of M. configurata after neuroendocrine events have initiated development, indicating that cyclic AMP acting via a cyclic AMP-dependent protein kinase may participate in brain differentiation. The high level of free and bound cyclic AMP in the adult brain may be related to an increased number of synapses and (or) the magnitude of synaptic activity and is in keeping with the increased activity of the cholinergic and octopaminergic systems also observed during brain ontogeny in lepidopterans.
Terrestrial feeding migration and life history of the stream-dwelling caddisfly, Desmona bethula (Trichoptera: Limnephilidae)
Authors: Erman Nancy A.
Published: April 2009

A caddisfly larva, Desmona bethula (Trichoptera: Limnephilidae), lives in slow, unshaded stretches of small spring streams at the Sagehen Creek Field Station in the Sierra Nevada, California, U.S.A. On early summer nights, while in the fifth instar, it leaves the water and feeds on several species of semiaquatic plants. It returns to the water when air temperatures approach freezing and on warm, still nights stays out until dawn. Three factors (light intensity, vapor pressure deficit and temperature) determine when diel migration begins and how long it lasts. Mark–recapture estimates indicated that 14–16% of the population migrated on 2 nights during the primary feeding period. Population estimates were 1220/m2 and 1662/m2. Desmona bethula is a univoltine autumn-emerging caddisfly. It may represent an evolutionary link between the few secondarily terrestrial Limnephilidae larvae and the majority of aquatic caddisfly larvae.
Ontogeny of spatial relationships and social behaviour in juvenile Richardson's ground squirrels
Authors: Michener Gail R.
Published: April 2009

The development of spatial and social patterns by juvenile Richardson's ground squirrels, from first emergence from the natal burrow to entry into hibernation, is described. Juveniles enter the aboveground population at [Formula: see text] weeks of age. During the next 4 weeks juveniles remain in close spatial proximity to family members with whom they engage in frequent amicable social interactions. Thereafter, juveniles become increasingly independent from the family unit, establishing their own spatially distinct core areas and exhibiting site-dependent dominance toward nonkin. Typically juveniles remain physically closer to and more amicable with littermates and mother than other conspecifics such that they compose kin clusters, the members of which are agonistic toward members of adjacent kin clusters. Daughters are more likely to continue to reside close to kin as adults than are sons. At 9–10 weeks of age juveniles exhibit the majority of spatial and social patterns characteristic of adults, and at 12 weeks they are behaviourally indistinguishable from adults. Similar rapid acquisition of adult patterns occurs in four other species of ground-dwelling sciurids that are also obligate hibernators and that breed immediately following emergence from their first hibernation.
Low pH affects the fertilization and development of Rana pipiens eggs
Authors: Schlichter L. C.
Published: April 2009

Effects of pH on fertilization and the early stages of development of the northern leopard frog, Rana pipiens, were investigated in the laboratory. Sperm motility decreased with decreasing pH below 6.5 in unbuffered solutions acidified with H2SO4 or HNO3, and below 5.5 in buffered solutions acidified with HCl. Motility was lower in the presence of HNO3 than in the presence of H2SO4. No eggs developed at pH 4.8 or below and this failure could not be attributed to low sperm motility. When eggs were inseminated in buffered solutions fertilization, activation, and cleavage decreased with decreasing pH below 6.3, falling to 50% of maximum at about pH 5.8. Fertilizing the eggs at pH 7.3, then transferring them to buffered solutions of lower pH, significantly improved the rate of survival in the first 24 h. Marked decreases in survival occurred at pH 5.8 or below, falling to 50% of maximum at about pH 5.5. By 48 h the embryos at pH 5.5 and 5.8 had stopped developing. Fertilization was more susceptible to low pH than was activation or cleavage. Provided eggs were fertilized, they continued developing at pH 6.0 to 7.5. Below pH 5.8, most fertilized eggs were activated but stopped developing before first cleavage. I concluded that waters more alkaline than pH 6.0 are optimal for fertilization and early development in R. pipiens.
Observations on the reproduction and development of Pisaster ochraceus (Brandt)
Authors: Fraser Alex , Gomez Johanna , Hartwick E. Brian , Smith Michael J.
Published: April 2009

Pisaster ochraceus was investigated as a potential source of embryonic material for molecular studies. Minimal conditions for laboratory maintenance of gravid sea stars and a method for induction of spawning are described. Data on oocyte size, yield, and fertilizability are presented as well as a timetable of normal development to bipinnaria larvae and measures of developmental synchrony.
Reproduction in three species of sea anemones from Key West, Florida
Authors: Jennison Brian L.
Published: April 2009

Reproduction in three species of sea anemones from Key West, Florida, was studied from October 1977 until July 1978. Condylactis gigantea is dioecious, has a 1:1 sex ratio, and exhibits an oviparous → planktonic → lecithotrophic reproductive pattern, based on the scheme of Chia, modified by the author. Phymanthus crucifer is also dioecious and exhibits a sex ratio not significantly different from 1:1; however, this species is viviparous. Bartholomea annulata exhibits imperfect gynodioecious hermaphroditism, accompanied by asexual reproduction by pedal laceration; it is oviparous → planktonic → planktotrophic. It is argued that an oviparous habit with resultant larval dispersal is advantageous to C. gigantea, which is solitary. In contrast, viviparity in P. crucifer and pedal laceration in B. annulata represent two different methods of keeping offspring close, thereby maintaining habitat space. The evolution of three such diverse reproductive modes is discussed through an examination of the morphology, prey, and habitat type of each species.
Increased juvenile hormone synthesis and decreased fertility in aging Schistocerca gregaria
Authors: Injeyan H. S. , Dale J. F. , Tobe S. S.
Published: April 2009

The fertility of aging Schistocerca gregaria females of both solitary and gregarious phases is markedly reduced in comparison with that of young females. Examination of eggs (from both young and aging females) maintained in vitro revealed that the decreased fertility of aging females of both phases could be attributed to a decrease in viability of eggs. This, in turn, was found to be in large part due to an increase in the proportion of embryos showing inhibited development. The proportion of inhibited embryos, in pods from young and old females, respectively, increased from 5 to 42% for gregarious animals and from 3 to 38% for solitary animals. Inhibition was found to occur at all stages from blastokinesis to ecdysis of the provisional cuticle. These morphogenetic aberrations were very similar to those obtained after treatment of S. gregaria eggs with exogenous juvenile hormone (JH). Investigation of the JH synthetic activity of corpora allata from aging females of each phase revealed a marked increase in the rates of JH synthesis in comparison with those of young females of the same phase. Furthermore, injection of JH into young females increased the proportion of embryos showing inhibited development from 7% (in control females) to 30% (in JH-treated females). These results suggest a possible correlation between reduced viability of eggs and high rates of JH synthesis in aging S. gregaria of both phases.
Density, food habits, and economic importance of raccoons (Procyon lotor) in Quebec agrosystems
Authors: Rivest Pierre , Bergeron Jean-Marie
Published: April 2009

During two years of trapping, in a sweet and field corn growing area in the Eastern Townships (P.Q.), population levels of raccoons based on a Lincoln index and on a Bell's equation varied from 0.17 to 2.90 individuals per hectare of corn. In 1978, corn, chokecherries, and raspberries were the main food sources. The following year spring foods, mainly invertebrates, were replaced during the summer by chokecherries, corn, hawthorn drupes, and apples. Corn and apples constituted nearly all of the food ingested in the fall of 1979. Corn crops are damaged yearly through being a staple in the diet of raccoons. Monetary losses to sweet corn were estimated at $61.03/ha in 1978 and $20.56/hain 1979. Field corn losses were very low, less than 1% of total crop biomass for both years. Damage levels varied from 10.61 kg/ha to 98.49 kg/ha implying monetary losses of $0.19/ha and $1.60/ha. Comparing the 1979 Canadian market value of $41.00 for a raccoon hide with the maximum crop loss of $4.42 per raccoon indicates that management of the species could be beneficial.
Interactions between free-ranging, adult male polar bears (Ursus maritimus Phipps): a case of adult social play
Authors: Latour Paul B.
Published: April 2009

I observed 73 dyadic interactions (bouts) between adult male polar bears (> 6 years) at Cape Churchill, Manitoba, from 4 October to 9 November 1978. All bouts involved at least one marked bear. I classified these bouts as social play and in this paper I discuss the criteria used for this classification. Social play bouts were composed of discrete motor acts and showed some predictability and structure. Two bouting bears respond to one another in a predictable manner as indicated by the mutuality of initiator-receiver acts. Structuring was suggested by a major three-act sequence for both initiators and receivers. Aggressive acts were found to be characteristic of initiators; the less aggressive, withdrawing acts were characteristic of receivers. The results are interpreted from both the structuralist and functionalist approaches to social play. I hypothesize that social play between adult male polar bears during the noncompetitive period of their annual cycle serves as a socialization process facilitating both opponent assessment and the refinement of social interaction. Both of these are probably important at times of the year when intraspecific competition is more intense.