bluuebunny/crossref_metadata_2025 huggingface dataset:
Perimicropylar filaments in eggs of Cyprinodontidae (Pisces, Teleostei)
Authors: Thiaw Omar Thiom , Mattei Xavier
Published: July 2008

We used a scanning electron microscope to observe the eggs of eight species of fishes belonging to the Cyprinodontidae: Aphyosemion geryi, Aphyosemion riggenbachi, Aphyosemion splendopleure, Epiplatys ansorgei, Epiplatys chaperi, Epiplatys fasciolatus, Epiplatys spilargyreus, and Fundulosoma thierryi. The secondary envelope organizes ornamentations on its surface, except for a localized zone at the animal pole that corresponds to the micropylar region. In certain species the micropyle closes on contact with water but can be identified by the absence of surface ornamentation in the area. The eggs of these fishes possess adhesive filaments that seem to be distributed over the whole surface. In the species studied here, the adhesive filaments are almost exclusively perimicropylar. In F. thierryi, the filaments are even present in the vestibule.
Functional aspects of maternal aggression in mammals
Authors: Maestripieri Dario
Published: July 2008

Evidence from several species of mammals suggests that the observed increase in female aggressiveness during lactation is aimed at protecting offspring from conspecifics. Whereas in rodents maternal aggression seems to constitute a deterrent against infanticidal behavior by adult males and females, in pinnipeds and primates its most likely function is to protect infants from general harassment by other individuals. Maternal aggression may also be involved in mate selection and function as a spacing mechanism. As an offspring defence behavior, maternal aggression can be considered a form of parental investment. As such, predictions can be made about its intensity in relation to the net effects it has on parental fitness. The functional aspects of maternal aggression suggest that this behavior should be analyzed in relation to other patterns of maternal care and investment in the offspring.
Parasites of yellowtail rockfish, Sebastes flavidus (Ayres, 1862) (Pisces: Teleostei), from the Pacific coast of North America as potential biological tags for stock identification
Authors: Stanley R. D. , Lee D. L. , Whitaker D. J.
Published: July 2008

We assessed the value of parasites of yellowtail rockfish, Sebastes flavidus (Pisces: Teleostei), as biological tags on the Pacific coast of North America. Of the 25 parasite species found, only Microcotyle sebastis (Monogenea: Microcotylidae) showed a latitudinal cline. Prevalence of this flatworm increased from 0–10% in samples from central British Columbia, to 80 and 100% in the California and Oregon samples, respectively. Mean intensity also increased from north to south. The results indicate that stock assessments for yellowtail rockfish, which treat the coastal population as five stocks from central British Columbia to northern California, can assume that harvests in one area will have little short-term impact on distant areas.
Auditory influences on the flight behaviour of moths in a Nearctic site. I. Flight tendency
Authors: Morrill Scott B. , Fullard James H.
Published: July 2008

We investigated the hypothesis that earless moths defend themselves from bats in a southeastern Ontario site by means of their flight behaviour. In this study we assume that the time taken by a moth to initiate flight from a stationary perch (flight tendency) will reflect its overall flightedness throughout the night. We predicted that earless moths would exhibit a reduced flight tendency relative to eared moths because moths at this site are primarily at risk of predation from bats while flying. When grouped, earless taxa displayed a significantly greater mean interval to flight departure than eared taxa. Most species of the earless families Saturniidae, Sphingidae, and Lasiocampidae were more likely to remain stationary and took longer to initiate flight than members of the eared families Noctuidae, Notodontidae, Geometridae, Arctiidae, and Drepanidae. We conclude that for most earless moths the hypothesis of reduced flight defence is supported, but there are exceptions to our results that suggest the existence of other antibat defences (e.g., seasonal isolation in a spring-emerging lasiocampid). The evolution of ears in moths and the potential reproductive costs of not possessing them are discussed.
Quantitative genetics of body size and development time in the parasitoid wasp Aphidius ervi (Hymenoptera: Aphidiidae)
Authors: Sequeira R. , Mackauer M.
Published: July 2008

Body size and development time are key components of life-history strategies and fitness in parasitoid wasps. To assess the relative importance of phenotypic variability for fitness, we determined the heritabilities and reaction norms of body size (= dry mass) and development time in Aphidius ervi, a solitary parasitoid of the pea aphid. We estimated the variance components for body size from an ANOVA model for haplodiploidy, using a half-sib design, with each of 18 sires mated to 2 or 3 dams. Phenotypic expression of body size was strongly influenced by host size (= instar) at the time of parasitization. Heritability for body size in female A. ervi, averaged over sire and dam components, was 0.38. Although the heritability for development time could not be estimated precisely, a larger dam than sire component suggests that development time has lower heritability than body size. Differences between the heritability estimates for body size in males and females indicate that the mode of inheritance and phenotypic expression may be asymmetrical. These results suggest that, in a stochastic environment, aphid parasitoids experience strong selection for rapid development; however, host-size effects are likely to mask differences in genetically determined body size. Genotype–environment interactions may play an important role in maintaining genetic variability in body size in natural populations of A. ervi.
Do molting birds renovate their skeletons as well as their plumages? Osteoporosis during the annual molt in sparrows
Authors: Murphy Mary E. , Taruscio Todd G. , King James R. , Truitt Sharon G.
Published: July 2008

Four decades ago two independent investigators reported a pronounced osteoporosis during the molt in several species of birds. With the exception of reports of statistically stable dry masses of bones in molting waterfowl this cyclic osteoporosis has received little additional attention. Using scanning electron microscopy and light microscopy we surveyed the tarsometatarsi and tibiotarsi of White-crowned Sparrows during winter and during the molt. A subtle change in bone metabolism appears coincident with the postnuptial molt in well-nourished White-crowned Sparrows. This is evident from (i) the appearance of the bone in cross section, (ii) decreases during the molt in bone density (g/mL), and (iii) increases during the molt in both the ratio of marrow-cavity area to total bone area and in the void area per unit area of cortical bone. Renovation of the bone during the molt in White-crowned Sparrows, however, appears either to proceed at a slower pace or to be less extensive than previously reported for other avian species.
Diet and condition of bobcats, Lynx rufus, in Nova Scotia during autumn and winter
Authors: Matlack Christopher R. , Evans Alison J.
Published: July 2008

A study was conducted from 1980 to 1982 on the diet and condition of bobcats, Lynx rufus, in the province of Nova Scotia. Skinned carcasses were provided by trappers, hunters, fur buyers, and taxidermists. The autumn–winter diet was determined from analysis of 1099 stomachs. Canine teeth were sectioned and aged to group the bobcats into three age-classes: juvenile, yearling, and adult. Snowshoe hare, Lepus americanus, occurred most frequently as a prey item, followed by white-tailed deer, Odocoileus virgìnianus, and small mammals. The mean weights of hare and deer consumed per feeding were similar. Male bobcats consumed deer more frequently and in larger quantities than did females. Adults consumed deer more frequently and in larger quantities than did juveniles. Bobcats harvested in the first year of the study (1980–1981) consumed deer more frequently than did those harvested in the second year (1981–1982), while hare population levels were found to be lower in the first year than in the second. A condition index was developed by dividing the sum of the weights of mesenteric, kidney, and sternum fat by the weight of the skinned carcass. The groups (males, adults, and specimens harvested in 1980–1981) that more frequently consumed deer were found to be in the best condition.
Genetic and morphological variation among populations of Oxyna parietina (Diptera: Tephritidae) across a European transect
Authors: Eber Sabine , Brandl Roland , Vidal Stefan
Published: July 2008

Genetic and morphological variation in the phytophagous tephritid Oxyna parietina (L.) was investigated across a transect through Central Europe by starch-gel electrophoresis to detect allozyme variation and by wing morphometrics. Very low allozyme differentiation was found on both a local and a regional scale, and is best explained by high rates and distances of gene flow. Nevertheless, there exists a smooth cline of allele frequencies from northern to southern populations. We tentatively interpret this cline as being a consequence of selection by environmental factors. The morphological patterns are not consistent with the allozyme data.
Effects of reproduction on maternal survival and subsequent reproduction in northern Peromyscus maniculatus
Authors: Millar John S. , Derrickson Elissa M. , Sharpe S. T. P.
Published: July 2008

Female survival, number of young weaned, and offspring survival were documented for 130 individual Peromyscus maniculatus in the Kananaskis Valley, southwestern Alberta. Reproductive success was highly variable, ranging from 0 to 19 young per female at weaning and from 0 to 12 young per female at the end of the breeding season. Breeding success was not related to body size of the female prior to breeding, and the commitment to reproductive processes had no negative effects on female survival or the survival of the offspring. Most of the variation in reproductive success was attributable to female survival. Females that survived the entire breeding season weaned, on average, twice as many young as females that did not survive the breeding season. We suggest that physiological and behavior compensation and local habitat effects mask potential costs of reproduction during the breeding season. We speculate that any negative effects of high reproductive success may be evident during the nonbreeding season, or prior to breeding in the spring.
Effect of stimulus frequency and duty cycle on force and work in fish muscle
Authors: Luiker Eric A. , Stevens E. Don
Published: July 2008

Stimulus trains of varying pulse number and pulse frequency were applied to the isolated pectoral adductor muscle of the sunfish Lepomis gibbosus. The number of pulses varied from 1 to 70, and the pulse frequency varied from 10 to 500 Hz. Muscle was continuously cycled at 2 Hz, and work was measured directly. Maximum force (177 kN/m2) was achieved with a train of 30 pulses at 169 Hz. Maximum work of 9.1 J/kg (power of 18.2 W/kg) was achieved with a train of 30 pulses at 169 Hz and a duty cycle (fraction of the cycle during which the muscle is activated) of 35%. Work values increased with an increase in the number of pulses per train, up to a maximum of 30 pulses. Duty cycle was the most important parameter in obtaining maximum work. The effect of varying stimulus pulse frequency on work values could not be accurately predicted from force values alone. For example, work increased 8-fold from twitch to maximum, whereas force increased only 2.6-fold.
Spatial variation of morphology in a freshwater population of the threespine stickleback, Gasterosteus aculeatus
Authors: Baumgartner Jeffrey V.
Published: July 2008

Differentiation with respect to two functional components of morphology, the defensive complex and overall body form, was studied in a population of threespine sticklebacks (Gasterosteus aculeatus) from the Brush Creek drainage, a small coastal system in northern California with high- and low-gradient habitats. The vast majority of body-shape differences among localities was accounted for by size-related allometric variation, the differences being closely related to overall growth trends. Relative to general body size, small individuals had long spines and fins whereas larger individuals tended to be deep bodied and have shorter fins and shorter spines. Significant size-independent differentiation with respect to the defensive complex and overall body form was also observed. The spatial pattern of differentiation in the components of the defensive complex changed dramatically over the period of study, possibly in response to natural selection. Stable stepped clines for overall body form and lateral-plate morph ratio were observed. Both clines were centered on the ecotone between high- and low-gradient habitats, and were apparently maintained by differential selection in alternative stream-gradient habitats despite gene flow across the ecotone. Sticklebacks from the high-gradient habitat had a continuous row of lateral plates, were elongate, and had long fins, whereas those from the low-gradient or standing-water habitat tended to have only abdominal plates, were more robust through the midbody, and had shorter fins. The results of this study and previous work suggest that various aspects of stickleback morphology may respond independently and rapidly to different evolutionary forces and be functionally related to hydrodynamics.
The Haemoproteidae (Apicomplexa: Haemosporina) of the avian families Fringillidae and Emberizidae s.l.
Authors: Burry-Caines Jennifer R. , Bennett Gordon F.
Published: July 2008

The haemoproteids of the avian passeriform families Fringillidae and Emberizidae s.l. are reviewed. In the Fringillidae, Haemoproteus fringillae of the Fringillinae is redescribed from the type host; within the Carduelinae, H. chloris is redescribed from the type host, and four species, H. globulosus, H. macropigmentatus, H. serini, and H. tartakovskyi, are synonymized with it. In the Emberizidae s.l. Haemoproteus quiscalus is redescribed from the type material, H. mazzai of the Cardinalinae is redescribed, and H. hedymelis is synonymized with it; H. coatneyi of the Emberizinae, H. paruli of the Parulinae, H. coereba of the Coerebinae, and H. thraupi of the Thraupinae are described as new species. A single taxon is recognized from each subfamily, and specificity at the subfamilial level is the primary taxonomic characteristic. The haemoproteid species involved are pleomorphic and are morphologically similar to one another.
Sexual differences in development and behaviour of larval Ischnura verticalis (Odonata: Coenagrionidae)
Authors: Baker Robert L. , Forbes Mark R. L. , Proctor Heather C.
Published: July 2008

The emergence period of Ischnura verticalis from a pond in southern Ontario lasted at least 97 days; the sex ratio of emerging larvae was not significantly different from 1:1. A 17-month study on larvae from the same pond indicated that the life cycle was univoltine and that male larvae tended to develop faster than female larvae. Analysis of instar distributions of larval I. verticalis collected from a series of ponds also indicated that males were in more advanced instars than females. In the laboratory, male I. verticalis larvae in the final instar developed faster than female larvae in the final instar but male and female larvae in the penultimate instar developed at approximately the same rate. Male larvae in the antepenultimate instar consistently spent more time moving and crawled farther than female larvae in the antepenultimate instar. Sexual differences in larval development and behaviour could help explain sexual differences in instar distributions and altered sex ratios at emergence.
The effect of armored skin on the swimming of longnose gar, Lepisosteus osseus
Authors: Webb Paul W. , Hardy Doug H. , Mehl Vicki L.
Published: July 2008

Fast-starts and steady swimming were compared for two piscivorous fishes, the longnose gar (Lepisosteus osseus), which has an integument armored with ganoid scales, and the unarmored tiger musky (Esox sp.). The body was similarly flexed by both species during fast-starts and steady swimming. Therefore, the heavy integument of the gar did not affect flexibility during swimming. Distance traveled in a given elapsed time during fast-starts was lower for the gar, which averaged 65% of the work done by the musky. On the basis of differences in muscle mass, gars would be expected to perform 72% of the work of muskies during a fast-start. The heavier integument of the gar was estimated to contribute about 90% to the reduced fast-start performance. In steady swimming, mechanical power requirements at a given speed were similar for both gar and musky. Therefore, steady swimming costs do not appear to be affected by armor. The critical swimming speed of gars was 1.9 body lengths/s compared with 3.4 body lengths/s for muskies, but the difference could not be attributed to differences in armoring. The slip speed at which gars first began to swim was 1.21 body lengths/s compared with 0.75 body lengths/s for muskies. Higher station-holding performance is probably not important to modern gars and esocids, but may have been advantageous during the early radiation of fishes.
The pholcid spiders of the Galápagos Islands, Ecuador (Araneae: Pholcidae)
Authors: Gertsch Willis J. , Peck Stewart B.
Published: July 2008

The 12 known species of the family Pholcidae in the Galápagos Islands are diagnosed, illustrated, and assigned to six genera as follows: Coryssocnemis conica Banks (for which a lectotype is designated), known from many islands; Coryssocnemis insularis Banks (for which a lectotype is designated), known from five islands; Coryssocnemis jarmila new species, a troglobite from Santa Cruz Island; Coryssocnemis floreana new species, a troglobite from Floreana Island; Hedypsilus culicinus Simon (for which a lectotype is designated), from Santa Cruz and San Cristóbal islands; Hedypsilus modicus new species, from San Cristóbal and Santiago islands (Modisimops Mello-Leitão is a NEW SYNONYM of Hedypsilus); Modisimus solus new species, from Santa Cruz Island; Pholcophora bella new species, from Santa Cruz Island; Pholcophora baerti new species, from Santa Fe and Pinta; Anopsicus banksi (Gertsch) from Floreana Island; Metagonia bellavista new species, a troglobite from Santa Cruz Island; and Metagonia reederi new species, a troglobite from Isabela Island. All are endemic to the islands, except H. culicinus, which is probably introduced. A stridulatory apparatus is reported on females of the genus Coryssocnemis for the first time. The troglobitic species of Coryssocnemis may have originated by parapatric speciation processes; the troglobitic species of Metagonia are relicts. In the troglobites the female epigynal characters are more differentiated than male palpal characters. A minimum of eight ancestral colonizations founded the Galápagos pholcid fauna.
Capillary–fiber geometrical relationships in tuna red muscle
Authors: Mathieu-Costello Odile , Agey Peter J. , Logemann Richard B. , Brill Richard W. , Hochachka Peter W.
Published: July 2008

The aim of this study was to examine the size and geometry of the capillary network in tuna red muscle, one of the most aerobic muscles in fish. Deep red muscle of 1.5- to 2-kg skipjack tuna, Katsuwonus pelamis, was perfusion fixed in situ, processed for electron microscopy, and analyzed by morphometry. Fiber cross-sectional area was 560 ± 30 (SE) μm2 in the samples. Capillary length per fiber volume was 4143 ± 242 (SE) mm−2 and mitochondrial volume density 28.5 ± 1.0 (SE) %. Indexes of capillarity such as average number of capillaries around a fiber, capillary length and surface per fiber volume, and capillary surface per fiber surface were high for a fish muscle. In fact, the size of the capillary–fiber interface (i.e., capillary to fiber surface) at a given mitochondrial volume per fiber was not significantly different in tuna red muscle compared with rat soleus muscle. However, calculation of mitochondrial respiratory rates in tuna red muscle yielded a substantially lower value (approximately 1/20th) compared with muscles of mammals. Besides the possible effect of differences in operating temperatures and (or) mitochondrial function(s) in fish compared with mammals, this suggests that the large capillary–fiber interface in tuna may be related to functions other than oxygen delivery per se, such as substrate and (or) heat transfer between capillaries and muscle fiber.
Gluconeogenesis in hepatocytes isolated from the skipjack tuna (Katsuwonus pelamis)
Authors: Buck L. T. , Brill R. W. , Hochachka P. W.
Published: July 2008

Skipjack tuna (Katsuwonus pelamis) hepatocytes were isolated and determined to be viable based on trypan blue exclusion, energy charge, and lactate dehydrogenase leakage. Trypan blue staining and red blood cell contamination were always less than 0.1%, and lactate dehydrogenase leakage remained less than 1% at 25 °C for 10 h. The energy charge for freshly isolated cells ranged from 0.65 to 0.74. Alanine (10 mM) gave higher rates of gluconeogenesis and oxidation than lactate: alanine rates were 3.17 ± 0.65 μmol glucose/(g packed cells∙h) and 9.1 ± 1.19 μmol CO2/(g∙h), whereas lactate rates were 0.47 ± 0.08 and 1.8 ± 0.27, respectively. Phosphoenolpyruvate carboxykinase was 30% cytosolic and 70% mitochondrial, a finding that is in agreement with the liver's ability to use both lactate and alanine as gluconeogenic substrates. If hepatic gluconeogenesis is the major route of lactate removal postexercise, it is estimated that recovery would require 3800 h! Therefore, tuna liver is not the major site of glucose resynthesis and lactate clearance following burst exercise.
Description of the Californian leech Helobdella robusta sp.nov., and comparison with Helobdella triserialis on the basis of morphology, embryology, and experimental breeding
Authors: Shankland Marty , Bissen Shirley T. , Weisblat David A.
Published: July 2008

This paper describes the leech Helobdella robusta, which was collected from the Sacramento delta of California. This new species is generally similar to another species found in California, Helobdella triserialis, and the two were compared in detail. In the adult, we observed reliable differences in the relative dimensions of the body, the size of the dorsal papillae, the pattern of cutaneous pigmentation, and the structure of the gut. In the embryo, we observed differences in the appearance of the yolk platelets and the size of the adhesive gland. We also observed differences in the rate of embryonic development. All of these differences persist in breeding populations that have been maintained in the laboratory over many generations. Experimental studies indicate that H. robusta and H. triserialis have little or no proclivity for interbreeding, supporting their distinction as separate species.
Enzyme gene variation in five species of bumble bees (Hymenoptera: Apidae)
Authors: Bregazzi Victoria , Laverty Terence
Published: July 2008

Genetic variability at eight enzyme loci was assessed in five bumble bee species from southern Ontario: Bombus affinis Cresson, B. fervidus (Fabricius), B. bimaculatus Cresson, B. impatiens Cresson, and B. vagans Smith. Average expected heterozygosity (Hexp ± SE) across all species was 0.089 ± 0.023 (range 0.046–0.139). These values are higher than any previously reported estimates of average expected heterozygosities for bumble bees.
Weaning in an arctic wolf pack: behavioral mechanisms
Authors: Packard J. M. , Mech L. D. , Ream R. R.
Published: July 2008

If behavioral mechanisms controlling suckling have been shaped by parent – offspring conflict in the ultimate sense, then proximate behavioral determinants of conflict should occur throughout lactation, with greatest intensity in the terminal phase, and offspring should have tactics for overcoming parental resistance. We observed the weaning process in a habituated wild wolf pack (Canis lupus) on Ellesmere Island, Canada, from estimated ages 5 through 10 weeks (including a continuous record for 192 h). The following variables declined with age: percentage of suckling bouts initiated by the nurser, persistence by pups, and mean duration of suckling bouts. Variables that increased with age were interbout interval, percentage of suckling bouts terminated by the nurser, and wincing or agonistic actions of the nurser. Behavioral conflict appeared in the developmental stage (estimated age 7 – 8 weeks) during which pups could feed on opened carcasses. Countertactics by pups to obtain milk were not apparent, although the pups developed diverse tactics for obtaining and sharing meat. In this group of wolves, weaning mechanisms were a complex function of food delivery by adults, discomfort of the nursing female as pups developed, and declining persistence of pups. If there is a conflict over what is optimal for pups and for the nurser in the ultimate sense, behavioral conflict is more likely to be expressed with regard to access to meat, or as conditional tactics dependent on food availability, rather than weaning conflict being controlled by fixed rules in this species.
Denning and home-range characteristics of breeding arctic foxes in Svalbard
Authors: Prestrud Pål
Published: July 2008

Home range, den density, and use of dens of arctic foxes (Alopex lagopus) in Svalbard were investigated through systematic den surveys, ear tagging of pups, and tracking of radio-collared animals. The mean home range for three breeding vixens was 48 km2. Home-range estimates based on occupied dens were between 46 and 75 km2. This is larger than recorded for arctic foxes elsewhere, and may be related to the absence of small mammals and, consequently, to a more scattered prey base in Svalbard. Home-range size was apparently not related to variations in the availability of food among years or among seasons. The density of all dens recorded was 1/24 km2. As a consequence of landscape patterns, these dens were more clustered than if they were randomly dispersed. However, dens with litters in 1986 (1 den/75 km2) were more widely spaced than if randomly distributed, indicating territoriality among arctic foxes. Most dens were in use throughout the year. Some litters were relocated or subdivided among several dens.
Dispersal of subadult moose (Alces alces) in a nonmigratory population
Authors: Cederlund Göran N. , Sand Håkan K. G.
Published: July 2008

Dispersal of subadult moose (Alces alces) in a sedentary population in central Sweden was studied during 1983 – 1989 by radio-tracking individuals for up to 11 seasons after their abandonment by the cow. Linear distance between geometric centers of natal area and consecutive home ranges increased with time among males, but not by more than about 4 km. The main increase occurred in autumn, probably due to rutting activities. Females maintained a fairly consistent distance of approximately 1 km throughout the study period. Seasonal home range overlap of natal area was negatively correlated with time for both sexes, but the patterns in the decrease differed. For males, the overlap was 10–40% after the first year, whereas female home ranges never overlapped by less than 40%. Overlap of consecutive seasonal home ranges increased significantly with age in both sexes. Neither sex dispersed out of the study area, since the animals were highly philopatric. The absence of dispersal (high philopatry) in moose in Fennoscandia is an important factor affecting demographic processes (and perhaps also genetic processes) within and between populations. It is important to distinguish different subpopulations of moose and manage them with respect to their unique demographic features.
Mass-transfer efficiency between hooded seal (Cystophora cristata) mothers and their pups in the Gulf of St. Lawrence
Authors: Kovacs K. M. , Lavigne D. M.
Published: July 2008

We investigated the efficiency of mass transfer in hooded seals (Cystophora cristata) through serial mass measurements on mother – pup pairs during lactation. Data on birth mass, weaning mass, pup growth, lactation duration, mass loss during the postweaning fast, and adult female mass were collected during the breeding seasons of 1988 – 1991. Pups weighed 24.4 ± 2.6 kg (mean ± SD, N = 19) at birth; males (25.3 ± 2.3 kg, N = 7) did not differ statistically from females (24.0 ± 2.7 kg, N = 12). During the nursing period pups grew at a rate of 6.9 ± 1.2 kg (N = 28) per day. Weaning took place at 3.8 ± 0.5 days of age (N = 19). Mass at weaning was not related to mass at birth. Pups were weaned at 47.1 ± 6.7 kg (N = 25). The mean value for weaning mass of males (47.6 ± 7.1 kg, N = 10) was not significantly different from that of females (46.7 ± 6.8 kg, N = 15). Ten percent of weaned pups stole milk from females after their own mothers had departed. Weaners, which consistently lost mass, did so at a rate of 1.3 ± 0.8 kg per day during the early part of the postweaning fast. At parturition, mean maternal body mass was 236.5 ± 35.5 kg (range 172 – 306 kg, N = 19). Mean maternal mass loss per day was 10.1 ± 2.6 kg. Efficiency of mass transfer from females to their pups was 63.2 ± 12.8% (N = 26).
The adhesive strength of the palettes of males of a boreal water beetle, Dytiscus alaskanus J. Balfour Browne (Coleoptera: Dytiscidae)
Authors: Aiken R. B. , Khan A.
Published: July 2008

The adhesive strength of specialized setae on the palettes of male Dytiscus alaskanus was investigated by recording the mass that palettes were able to lift. Large primary and secondary adhesive setae were removed and the adhesive strength of the palette was tested. The primary and secondary adhesive setae accounted for 59.5% of the adhesive strength of the palette. The ability of the palette to hold nearly 4 times the mass of a female may be needed to overcome the force generated by an accelerating female.
Winter digestive strategy of a concentrate selector in Norway: the European roe deer
Authors: Holand Øystein
Published: July 2008

Seasonal variations in gut contents were measured in 63 adult roe deer (Capreolus capreolus) collected in the southeastern part of Norway. Gut contents were 50% greater in animals collected in winter than summer. This resulted from an increase in the contents of the rumeno-reticulum and, to some extent, the distal fermentation chamber (caecum and proximal colon). The winter digestive strategy of the roe deer was in accordance with the optimal digestion theory, i.e., given gut capacity as a limiting factor, the digestive system should hold more, allowing a longer retention time and more complete digestion of the less nutritious winter diet. This seasonal digestive adaptation in the roe deer underlines the importance of a flexible nutritional strategy in a highly seasonal environment for winter survival in concentrate selectors.
Hemoparasites of wading birds (Ciconiiformes) in Florida
Authors: Telford Jr. Sam R. , Spalding Marilyn G. , Forrester Donald J.
Published: July 2008

Eight species of hemoparasites (Plasmodium relictum, Plasmodium elongatum, Plasmodium sp.indet., Haemoproteus plataleae, Haemoproteus herodiadis, Haemoproteus sp.indet., Leucocytozoon ardeae, and Trypanosoma avium) were found in thin blood films from 402 wading birds in Florida. Three of 11 ciconiiform species were infected, including the tricolored heron (Egretta tricolor), white ibis (Eudocimus albus), and two subspecies of Ardea herodias, the great blue heron (Ardea herodias herodias) and great white heron (Ardea herodias occidentalis). Representatives of each genus of hemoparasite except Leucocytozoon were recorded in nestlings, indicating that transmission occurred in Florida. Infections by L. ardeae were more common in northern Florida than in southern Florida. Species of Plasmodium and Haemoproteus were more commonly transmitted to nestling great blue herons in freshwater colony sites than in salt-water colony sites.
Body composition changes in white-tailed deer fawns during winter
Authors: Watkins Bruce E. , Witham James H. , Ullrey Duane E.
Published: July 2008

Sixteen white-tailed deer (Odocoileus virginianus) fawns were captured near Chicago, Illinois, between November and April, and their body composition was determined, to investigate changes in body composition and chemical component distribution as they catabolized tissues over the winter. Live weights of the fawns ranged from 16.8 to 41.6 kg (31.1 ± 2.0), and ether-extractable fat concentration of the bled, ingesta-free body ranged from 2.3 to 48.9% (24.5 ± 4.7) on a dry basis. Carcass, viscera, and hide contained, on average, 70, 21, and 9% of the bled, whole body fat, respectively. Above approximately 15% whole body fat (dry basis), the percentages of whole body fat contributed by the viscera and carcass increased and decreased, respectively. Body composition (blood-, ingesta-, and fat-free basis) averaged 72% water, 23% crude protein, and 5% ash; ash and phosphorus concentrations increased and protein concentration decreased over the winter. Sodium concentration tended to decrease. Based on relationships between chemical components and body weight, the composition of weight lost during winter was calculated to range from 12% water, 84% fat, 4% protein, and 0.5% ash during early winter to 73% water, 0.3% fat, 25% protein, and 2% ash during early spring. Calculated metabolizable energy derived from tissue catabolism was a quadratic function of body weight and ranged from 7.7 to 1.1 Mcal/kg of bled, ingesta-free weight loss during early and late periods.
Song-type matching in the song sparrow
Authors: Stoddard Philip K. , Beecher Michael D. , Campbell S. Elizabeth , Horning Cynthia L.
Published: July 2008

Song playback to song sparrows (Melospiza melodia) in a resident population in Washington state showed that the tendency of birds to respond with the same song type (match) depended on the identity of the singer. Matching rates were high to 'self song (60%) and 'stranger' song (50%) and low to 'neighbor' song (20%, not significantly above chance level). The higher matching rate to stranger song was particularly interesting, since the neighbor test songs were generally more similar to the subjects' songs than were the stranger test songs (the self songs, of course, were the most similar). The importance of the neighbour–stranger contrast, in addition to song similarity, in eliciting song matching confirms similar conclusions from earlier studies on the great tit (Parus major) and western meadowlark (Sturna neglecta).
Redescription of Diacyclops nearcticus (Kiefer, 1934) and description of four similar new congeners from North America, with comments on D. crassicaudis (G. O. Sars, 1863) and D. crassicaudis var. brachycercus (Kiefer, 1927) (Crustacea: Copepoda)
Authors: Reid J. W.
Published: July 2008

Diacyclops nearcticus is redescribed from the type specimen, collected in Massachusetts, U.S.A. Four similar new congeners, some previously mistaken for D. nearcticus, are described from the U.S.A. and Canada. Diacyclops harryi n.sp. occurred in seeps, wells, an acid bog, a pitcher plant, and stream hyporheic zones in the District of Columbia, Maryland, New York, North Carolina, Pennsylvania, and Virginia. Diacyclops chrisae n.sp. was collected from the groundwater of Wye Island, Maryland, with a probable record from the hyporheic zone of a stream in Ontario. Diacyclops sororum n.sp. occurred in drift in streams in Virginia and Texas. Diacyclops alabamensis n.sp. was collected from a well in Alabama. A previous record of D. nearcticus from Missouri could not be confirmed. Some morphological details of the probable type specimens of D. crassicaudis var. brachycercus and of a specimen of D. crassicaudis s.str. from Saskatchewan are presented. North American records of D. crassicaudis s.str. and D. crassicaudis var. brachycercus are reviewed.
Age at attainment of sexual maturity in humpback whales, Megaptera novaeangliae
Authors: Clapham Phillip J.
Published: July 2008

Twelve female humpback whales (Megaptera novaeangliae) in the southern Gulf of Maine produced first-observed calves at ages ranging from 5 to 7 years. These data confirm that most females of this species attain sexual maturity at an average age of approximately 5 years. Observations in the West Indies of two males, aged 6 and 7 years, engaged in breeding-related behavior that is characteristic of mature animals suggests that males attain sexual maturity within a similar range of ages to females, although they may not be able to successfully engage in intrasexual competition until later in life. These data imply that the examination of ear plugs to determine the age of dead humpback whales should be based upon an assumed annual growth rate of two growth layer groups, not one.
Avoidance of areas marked with a chemical alarm substance by fathead minnows (Pimephales promelas) in a natural habitat
Authors: Mathis Alicia , Smith R. Jan F.
Published: July 2008

If chemical alarm pheromones warn individuals of nearby predation on conspecifics, then individuals should avoid areas where alarm pheromone is present. This hypothesis was tested in a natural stream habitat by exposing fathead minnows (Pimephales promelas) to minnow traps that had been marked with either conspecific alarm pheromone or with a control substance (glass-distilled water). The minnows exhibited significant avoidance of traps marked with the alarm pheromone: less than 4% of the minnows that were captured were found in the experimental traps. There was a nonsignificant tendency for minnows in control traps to be larger than those caught in experimental traps, suggesting a possible role of experience or developmental factors in determining the response to alarm pheromone. There was no apparent difference in overall body condition (i.e., length-specific mass) between the minnows that were caught in control versus experimental traps. Detection of the alarm pheromone may allow receivers to avoid areas where risk of predation is high.
Breeding ecology of urban Merlins (Falco columbarius)
Authors: Sodhi Navjot S. , James Paul C. , Warkentin Ian G. , Oliphant Lynn W.
Published: July 2008

We studied the breeding ecology of Merlins (Falco columbarius) in Saskatoon, Saskatchewan, Canada, from 1971 to 1990. The nesting population increased from 1 pair in 1971 to a maximum of 31 pairs in 1989. At 25.4 pairs/100 km2, the 1989 nesting density is the highest recorded for this species. The population increased at a rate of 0.165 ± 0.015, or 17.9%, per year. The growth rate of the population declined, although not significantly, with increasing density. Merlins spaced their nests regularly, with nearest-neighbour distances ranging from 161 to 4669 m. Clutches were initiated between 19 April and 29 May. Earlier clutches had more eggs and produced more young. Weather did not appear to influence the breeding phenology, but fledgling House Sparrows (Passer domesticus, the primary prey) were maximally available when Merlins had their chicks. The reproductive success of this population was one of the highest recorded for this species. In only 4% of the nests did any eggs fail to hatch. The mean and modal clutch sizes were 4.2 ± 0.04 (SE) and 5, respectively, and mean and modal brood sizes were 3.8 ± 0.03 and 5, respectively. We did not observe any significant effect of nesting density on either clutch or brood size. Males delivered most of the food and were most active in nest defence against corvids, while females primarily incubated, brooded, and fed the nestlings. This expanding Merlin population had higher and more consistent reproductive rates than other populations.
Sexual dimorphism in the baiji, Lipotes vexillifer
Authors: Anli Gao , Kaiya Zhou
Published: July 2008

Dimorphism was detected in body length and in skull dimensions of the baiji, Lipotes vexillifer. The age of a sample comprising 22 females and 14 males was estimated. A single-phase Laird growth model was fitted to the body length versus age data for females. Two curves were required for the males, one for those with 4 dentinal growth layer groups (GLGs) and another for those above that age, i.e., with more than 4 GLGs. Males and females have about the same growth rate until they have about 4 GLGs, after which males grow more slowly than females. Sexual dimorphism was also found in 9 external measurements, based on t-tests. Analysis of covariance showed that once the effect of body length was removed, only 1 of the 9 measurements, from the tip of the upper jaw to the genital aperture, differed significantly between males and females. Differences in skull measurements resulted mainly from an early slowdown in the rate of longitudinal growth of the male, before the increase in body length slowed. Females and males could be correctly sexed by discriminant analysis using the body length, condylobasal length, and zygomatic width, and also the condylobasal length, width of the rostrum at the base, and the zygomatic width, except for one young female. Eight skull length measurements were greater in adult females than in adult males after the effect of body length was removed, and five skull width measurements were greater in males when the effect of condylobasal length was removed. Asymmetry in the position of the blowhole and in skew of the skull is pronounced and is independent of body length and sex.
Distribution of wolf dens on migratory caribou ranges in the Northwest Territories, Canada
Authors: Heard D. C. , Williams T. M.
Published: July 2008

Most wolves (Canis lupus) on migratory caribou (Rangifer tarandus) ranges in the Northwest Territories den near the tree line, the northern limit of tree growth. Sixty percent of the 209 dens that we located were within 50 km of the tree line, an area representing only 25% of the caribou range. Den density in the forest was significantly lower than expected if dens were randomly dispersed. Within the tundra zone wolves did not show any preference for denning near caribou calving grounds. Most wolves may den at the tree line because caribou are likely available for a greater proportion of the denning period than they would be elsewhere and because caribou are usually abundant near the tree line in September, when the nutritional demands of the pups are greatest. Within the tree-line zone, habitat characteristics appeared to affect the local distribution of dens because wolves preferred to den where the roots of trees and shrubs provided structural support for the tunnels. With most wolves denning at the tree line, density-dependent summer range expansion and contraction by caribou may provide a mechanism by which changing caribou densities could influence the growth rate of the wolf population.
Optimal litter size: Does it cost more to raise a large litter in Caluromys philander?
Authors: Atramentowicz Martine
Published: July 2008

Food intake of lactating Caluromys philander, a didelphid marsupial, was recorded from parturition until weaning of the pouch young. Variation in the average caloric value of daily food intake throughout lactation, in relation to litter size, showed no significant differences, but females increased food intake during late lactation, prior to weaning. Food intake was positively correlated with total litter mass at weaning. Moreover, there were significant differences in body mass and body length of offspring at first pouch exit (3 months) and at weaning (4 months): young born in small litters (1–3) were bigger than those born in large litters (6–7). Reproductive success is discussed on the assumption that pouch-young survival depends on food resources.
The influence of dietary protein and caloric content on thyroid function and hepatic thyroxine 5′-monodeiodinase activity in rainbow trout, Oncorhynchus mykiss
Authors: Eales J. G. , MacLatchy D. L. , Higgs D. A. , Dosanjh B. S.
Published: July 2008

The influence of dietary protein and caloric intake on thyroid function of immature rainbow trout (6.5 °C; 12 h L: 12 h D photocycle) fed a daily ration of 0.97% of body weight was studied. In experiment 1, trout fed four isocaloric diets (~ 3300 kcal of estimated metabolizable energy/kg; 1 cal = 4.1855 KJ) of identical digestible carbohydrate content (15.2%) but with varying percentages of lipid (7.5–17.6%) and protein (25.6–47.5%) exhibited negligible or modest changes in plasma L-thyroxine (T4) or 3,5,3′-triiodo-L-thyronine (T3) after 7 or 35 days. After 14 days, activity of hepatic 5′-monodeiodinase (5′D), which converts T4 to the active T3 form, was unaltered. However, at 38 days the functional level (Vmax) of 5′D was directly related to the level of protein intake. Substrate affinity (Km) was unchanged. In experiment 2, trout fed four isocaloric diets (~ 3575 kcal/kg) of similar lipid content (15.8%) but with varying percentages of digestible carbohydrate (3.6–54.2%) and protein (0.32–47.1%) generally showed unaltered plasma T4 after 7 or 35 days, but plasma T3 was depressed by the lowest dietary protein levels. Activity of 5′D was unaffected at 14 days, but at 38 days Vmax was directly related to the level of protein ingested; Km was not changed. Trout pair-fed diets of the highest protein content to achieve levels of protein intake equivalent to those of trout fed diets of lower protein content showed a depressed Vmax but no changes in Km or plasma T4 or T3 levels. We conclude that the level of protein intake in trout mainly determines the activity of 5′D, which is a more sensitive index of chronic thyroidal adjustment than plasma T4 or T3 levels. However, the amount of ingested protein relative to total available dietary energy and (or) the absolute intake levels of one or more nonprotein nutrients change 5′D activity, possibly by influencing the balance between protein synthesis and degradation.
Statoblast morphology and systematics of the freshwater bryozoan Hyalinella orbisperma (Kellicott, 1882)
Authors: Ricciardi Anthony , Wood Timothy S.
Published: July 2008

The freshwater bryozoan Hyalinella orbisperma (Ectoprocta: Phylactolaemata), previously known only from Michigan, is added to the list of Canadian fauna from a specimen collected at Georgian Bay, Ontario. Floatoblasts match the appearance of those described from Michigan. The sessoblast of this species is recorded and illustrated for the first time. The case for other species with sessoblasts in the genus Hyalinella is extremely weak. Scanning electron microscopy of the floatoblast and sessoblast reveals a raised reticulation with interstitial tubercles covering the capsule periblast, suggesting a close phylogenetic relationship with certain Plumatella species. It is proposed that H. orbisperma be reassigned to the genus Plumatella.
Effects of age and body weight on the proportion of females breeding in a population of roe deer (Capreolus capreolus)
Authors: Gaillard Jean-Michel , Sempéré Antoine J. , Boutin Jean-Marie , Laere Guy Van , Boisaubert Bernard
Published: July 2008

The reproductive state of female roe deer (Capreolus capreolus) (n = 140) caught during 4 consecutive winters (January and February) was determined from progesterone concentrations in blood samples. We found that (i) females older than 20 months were pregnant almost every year, indicating that though monoestrous, this species can achieve a very high conception rate (98%); (ii) a significant proportion of females 20 months of age (corresponding to the usual age at first pregnancy) had not reached sexual maturity; and (iii) body weight measured in winter could be used to predict the probability of pregnancy for young females (20 months of age) but not for older females. The correlation observed between age, body weight, and reproductive success suggests the hypothesis that the proportion of young females that breeds is density dependent. Ecological conditions mediated by social behaviour and prevailing during the spring of birth could constitute the ultimate factor determining pregnancy rate at 20 months.