bluuebunny/crossref_metadata_2025 huggingface dataset:
Passage of Harderian gland secretions to the vomeronasal organ of Thamnophis sirtalis (Serpentes: Colubridae)
Authors: Rehorek S J , Hillenius W J , Quan W , Halpern M
Published: April 2011

The Harderian gland is a poorly understood structure found in the anterior orbit of most terrestrial vertebrates. In colubrid snakes it is a seromucous gland with a large postorbital portion. Numerous functions have been ascribed to this gland, including contributions to orbital lubrication or the vomeronasal system. Anatomically the Harderian gland is connected to the vomeronasal organ (VNO) via the nasolacrimal duct. In this study we traced the serous secretions of the Harderian gland of two subspecies of Thamnophis sirtalis (Colubridae), using autoradiographic techniques at the light-microscopic level. We injected the Harderian gland of the snakes with H3-proline either unilaterally (right side) or bilaterally. The right Harderian glands of both treatment groups were then injected with a potassium-rich solution. No labeling was observed in the orbital space of any treatment group, suggesting that the Harderian gland secretions of T. sirtalis do not function in orbital lubrication. Labeling was only observed in the right Harderian gland, Harderian gland ducts, nasolacrimal duct, apical vomeronasal sensory epithelium, VNO lumen, and vomeronasal duct. No such labeling was observed in any of the other treatments examined. Thus, the serous secretions of the Harderian gland in snakes flow to the VNO, and may be considered part of the vomeronasal system. The specific function of the Harderian gland secretions in the vomeronasal system remains to be determined.
Free choice by female sticklebacks: lack of preference for male dominance traits
Authors: Nilsson Sara Östlund , Nilsson Göran E
Published: April 2011

To experimentally assess if a male sexual trait has an influence on female choice and (or) male-male competition, it is essential to separate these two evolutionary forces. Female choice may be obscured by the overriding influence of male-male competition, and it may therefore appear that female interests coincide with male dominance. We approached this problem using the threespine stickleback, Gasterosteus aculeatus, by leashing the males, allowing the female to fully interact and mate with each male, while physical interactions between the males were prevented. Our results show that in this situation, females display no preference for dominant males and no, or only a weak, preference for more colorful males. When the males could interact freely with each other, females "chose" the dominant and the more colorful males, but in this case the dominant male always deprived the female of the opportunity to interact with the subordinate male. When the females were separated physically from the males by glass walls, they demonstrated a preference for males with the most intense red color. This suggests that if females are given only a limited number of cues on which to base their choice (by introducing glass walls), they are attracted to the redness of the males, while in a situation involving free physical and sensory interaction, other factors become more important for females' choice if they have the possibility to make a free choice in the absence of forceful male-male interactions.
Variation in life-history traits of Plasmodium mexicanum, a malaria parasite infecting western fence lizards: a longitudinal study
Authors: Eisen Rebecca J
Published: April 2011

The life history of malaria parasites (Plasmodium spp.) is directly related to their transmission, virulence, and population dynamics. I followed the life history of Plasmodium mexicanum in naturally infected western fence lizards (Sceloporus occidentalis) over a 4-year period, using a mark-recapture technique. The life-history traits measured included peak parasitemias and population growth rates of asexual forms, gametocytes, and total parasites. Among malaria infections, variation was high for all measured traits. Growth rates varied up to 11-fold, and among stable infections, average asexual parasitemias ranged from 0.2 to 13.2 and gametocytemias from 0.5 to 66.2 parasites per 1000 erythrocytes. This variation was not related to infection prevalences, which were similar among years and between male and female hosts. Host age and gender were not related to peak parasitemia or average growth rate of asexual forms. However, the growth rate of gametoctyes was higher in older lizards. Gametocytemia and parasitemia were significantly higher late in the warm season, when sand-fly vectors are active. These data reveal that life-history traits of P. mexicanum are highly variable within an infected host population, and that the variation is partially related to the age of the infected host or the time of year the host was examined.
Long-term study on the susceptibility to Trypanosoma congolense infections and genetics of colonized Glossina pallidipes from allopatric populations in Kenya
Authors: Moloo S K , Gooding R H
Published: April 2011

Two colonies of Glossina pallidipes originating from the Shimba Hills and Nguruman, Kenya, were examined for their susceptibility to two strains of Trypanosoma congolense and for allele frequencies at eight polymorphic loci. These data were compared with data from earlier studies of these colonies. Overall, the two colonies of G. pallidipes were found to have lost, over 3-4 years, most of the genetic and trypanosome-susceptibility characteristics that originally distinguished them.
Evidence for geographic variation in colony social organization in an obligately social sweat bee, Lasioglossum malachurum Kirby (Hymenoptera; Halictidae)
Authors: Richards Miriam H
Published: April 2011

The expression of altruism and colony eusociality are both a matter of degree in social sweat bees. Even in obligately social species, variation in these traits may be observed across a species' range. Lasioglossum (Evylaeus) malachurum (Kirby) is an obligately eusocial sweat bee found across Europe. In western Europe, L. malachurum exhibits north-south clines of increasing colony size associated with the production of more worker broods, and worker production of males, but societies conform to the model of a classically eusocial hymenopteran insect. A population of L. malachurum studied from 1994 to 1998 at Agios Nikolaos Monemvasias in southern Greece exhibits a startlingly different type of social structure. Dissections of female bees collected while foraging on flowers or from excavations of nests showed that the majority of mid- to late-summer workers are mated and (or) have developing ovaries, indicating that some workers are highly reproductive. Nest excavations indicated that in many or most colonies, the queen has disappeared by midsummer, before ovipositing the final, reproductive brood. In orphan nests, workers become the major reproductives, which suggests that males and gynes in the final brood are the offspring of workers. The very long breeding season in southern Greece may explain why colonies often outlive their queen. The result is the expression of a multivoltine colony cycle and a behavioural switch from eusocial to semisocial colony organization.
Assessment of source-sink theory for predicting demographic rates among habitats that exhibit temporal changes in quality
Authors: Virgl John A , Messier François
Published: April 2011

Within the framework of Pulliam's source-sink model we tested predictions of habitat-specific demography on a "closed" population of muskrats (Ondatra zibethicus L.) occupying three contiguous habitats that exhibited temporal changes in quality and quantity. We were able to distinguish between dispersal among habitats and mortality within each habitat, and induce temporal variation in operational-habitat availability and suitability by manipulating water level. Temporal variation in population size and density among habitats supported the source-sink model and was primarily associated with habitat-specific survival rates. For example, the mean annual over-winter mortality rate of individuals in the principal source habitat (0.87) was less than in the sink habitat (0.94), and subsequently the mean annual finite rate of increase (λ) was positive in the source habitat (λ = 1.41) and negative in the sink habitat (λ = 0.90). The high recruitment rate of juveniles in the prime habitat during autumn was also associated with significant emigration of juveniles from this habitat. Emigration of adults among habitats provided support for the role of spacing behaviour in regulating the breeding density of muskrats in prime habitat. However, in contrast to the assumption of source-sink theory, year-to-year variation in survival rate in the more marginal habitats appeared to be explained more by temporal changes in habitat suitability than by density. Significant emigration of juveniles from the sink habitat was not predicted and was largely dependent on current habitat conditions. In addition, the mean annual emigration rate was lowest in the principal source habitat (0.30) and highest in the more marginal habitats (0.62). Failure to detect directional emigration from prime to marginal habitats in the spring, as predicted by the source-sink model, was likely due to declining local population size. In environments where spatial differences in habitat quality are not static, and annual change in local population size is largely independent of density, current source-sink models must be modified to better predict individual dispersal strategies.
Influence of the density of a sika deer population on activity, habitat use, and group size
Authors: Borkowski Jakub
Published: April 2011

The influence of population density of sika deer (Cervus nippon) on their activity, habitat use, and habitat-related group size was studied in the area of Japan's Tanzawa Mountains in early winter. The percentage of active sika deer was higher in January 1994 (a low-density period) than in January 1995 (a high-density period). The pattern of habitat use differed between periods. During the high-density period, deer increased their relative use of lower quality habitats. A possible mechanism and implications of this are discussed. Changes in population density had a positive effect on group size in sika deer, though the variation among habitat types supported the hypothesis that food biomass is an important determinant of group size.
Differential responses of Clethrionomys species to forest disturbance in Europe and North America
Authors: Gliwicz Joanna , Glowacka Beata
Published: April 2011

In Holarctic forests, newly disturbed areas constantly appear as the result of clear-cutting and burning. Rodent communities in mature forests of Europe and North America are comparable, being dominated by a Clethrionomys species: Clethrionomys glareolus in Europe and Clethrionomys gapperi in America. In disturbed areas, however, they differ considerably, as C. glareolus persists on clearcuts in the Palearctic region, while in the Nearctic region, C. gapperi is replaced by Peromyscus species. Meta-analysis was applied to published data to summarize inter continenal differences. The aim of this paper is to explain why C. gapperi is not as successful as C. glareolus in colonizing disturbed areas, and to support one (or more) of the following hypotheses: (i) Peromyscus species are more suited to colonizing disturbed areas than other rodents; thus, the absence of Peromyscus species in Europe leaves the disturbed habitats free for C. glareolus; (ii) C. glareolus is more of a generalist and therefore better adapted for resettling such areas than C. gapperi; (iii) the long historical period of human management of forests has affected the niches of rodents, and thus their ability to colonize disturbed areas. The data analyzed indicate that the second hypothesis best explains the ultimate cause, while the third presents a probable proximate cause of the stated difference.
Why bears consume mixed diets during fruit abundance
Authors: Rode K D , Robbins C T
Published: April 2011

In many ecosystems, grizzly bears (Ursus arctos) and black bears (Ursus americanus) feed heavily on berries and fruits in the fall. While a few birds and mammals are exclusively frugivorous, bears and most other animals consume fruit as part of a mixed diet. The mixed-diet strategy avoids potential calcium, protein, amino acid, or other nutrient deficiencies that can occur on fruit diets. However, we hypothesized that the high carbohydrate - low protein content of fruit would increase energy metabolism and force bears to use dietary mixing to meet protein requirements and, thereby, reduce energy metabolism. We examined the effects of six plant-based diets containing from 2.3 to 35% crude protein on intake, maintenance costs, and efficiency of gain of captive grizzly and black bears. In addition, the food habits of six populations of wild grizzly and black bears were analyzed, to determine the crude protein and digestible dry matter content of their diets. Efficiency of gain (0.53 ± 0.02 (±SD) g gain/g digestible dry matter intake) did not differ across diets. However, maintenance costs differed, ranging from 24 g·(kg0.75·day)-1 (120 kcal (1 cal = 4.1868 J) digestible energy (DE)·(kg0.75·day)-1) on the 35% protein pelleted diet to 80 g·(kg0.75·day)-1 (340 kcal DE·(kg0.75·day)-1) on fruit diets containing 2.3-5.6% protein (P = 0.0001). Supplementation of the fruit diet with additional protein increased mass gain but did not completely reverse the growth-depressing effect of the fruit-only diet. Protein limitations or other characteristics of fruit diets that increase energy metabolism and intake may be strategies that also directly benefit plants, by increasing either seed dispersal or propagation.
Determining the effect of negative allometry (length/height relationship) on variation in otolith shape in lake trout (Salvelinus namaycush), using Fourier-series analysis
Authors: Simoneau Michel , Casselman John M , Fortin Réjean
Published: April 2011

Geometric mean regression analysis between log(length) and log(height) of otoliths from lake trout (Salvelinus namaycush) from six lakes revealed that the growth of this structure was negatively allometric, indicating that otolith shape varies throughout the life of the fish. Otolith shape was quantified using harmonic amplitudes 2-10 (A2-A10) extracted from Fourier-series analyses. We found harmonic amplitudes 2 (A2) and 5 (A5) to be associated with the length/height relationship. Some recent studies have suggested that growth of fish otoliths affects their shape. Our results indicate that part of this otolith-growth effect could be due to an intrinsic change in shape associated with allometric nature of the length/height relationship. There were no differences in otolith shape between males and females. Otolith shape was also compared among the six populations. Major differences were observed between Lake Normand (Saint Maurice River watershed) and the five lakes in the Ottawa River watershed, suggesting that genotype could be an important factor affecting otolith shape. The percentage of reclassification using a discriminant function analysis was high (86%) for the Lake Normand population. Among populations from the Ottawa River watershed, differences in otolith shape were more subtle, with reclassification percentages ranging from 50 to 75%. However, one population in the Ottawa River watershed (Lake Duval), which was introduced as hatchery-raised individuals, differed slightly from the other populations from the same watershed, including Lake Trente et un Milles, from which it originated.
Swimming performance of walleye (Stizostedion vitreum)
Authors: Peake S , McKinley R S , Scruton D A
Published: April 2011

Swimming performance of walleye (Stizostedion vitreum) from a wild population was measured relative to fork length (0.18-0.67 m) and water temperature (5.8-20.5°C), to provide models for setting water velocities in fishways and culverts. Ucrit60(the highest speed maintainable for 60 min) values ranged from 0.30 to 0.73 m/s and increased significantly with length and temperature. Ucrit10(the highest speed maintainable for 10 min) values ranged from 0.43 to 1.14 m/s and also increased significantly with fish length and water temperature. When startled, walleye were able to attain higher speeds (1.60-2.60 m/s) during short (temperature-independent) bursts of swimming activity. The relatively low Ucrit60values suggest that walleye possess a narrow scope for aerobic activity compared with other species, which may account for their poor performance in fishways. However, the small differences between Ucrit60and Ucrit10values and the large differences between Ucrit10and fast-start performance suggest that low passage efficiency may be caused by a behavioural disinclination to switch from low to high intensity activity.
Weather effects on intrahabitat movements of the western green lizard, Lacerta bilineata (Daudin, 1802), at its northern distribution range border: a radio-tracking study
Authors: Sound P , Veith M
Published: April 2011

Daily activity patterns of male western green lizards, Lacerta bilineata (Daudin, 1802), at the edge of their northern distribution range in western Germany after the breeding season from June to October were recorded using implanted radio transmitters. Different activity indices discriminating between stimulation, duration, and length of movement were correlated with actual weather conditions (d0) and with weather conditions on the 2 previous days (d-1 and d-2). The lizards' dependence on weather showed two different phases throughout the study period. During the first period and in the period preceding a drastic change of weather in midsummer, weather had no significant influence on movement parameters. After that event, temperatures dropped and a strong dependence on weather of all movement parameters except those indicating displacements became apparent. Thresholds for 50% activity during this second phase were a maximum temperature of 17°C and a minimum humidity of 35%. Two days after periods of bad weather, the influence of weather conditions increased again. This can be explained by physiological deficits that require compensation during the period of marginal weather conditions prior to hibernation. Displacement movements were significantly longer than home-range movements and were neither triggered nor modulated by the weather. They must therefore represent activities such as patrolling territory boundaries.
Behaviour and daily activity of the squirrel Sciurus ingrami in a secondary araucaria forest in southern Brazil
Authors: Bordignon Marcelo , Monteiro-Filho Emygdio LA
Published: April 2011

A study on the behaviour of a population of squirrels, the "serelepe" (Sciurus ingrami), was conducted in a secondary araucaria forest in southern Brazil. Forty-three squirrels were marked and observed between 05:00 and 18:00 daily. The largest number of males were trapped during the winter, coinciding with an increase in the number of agonistic encounters and mating chases. Two peaks in occurrence of trapped pregnant females were found, one during the winter and the other in the summer. The population density was 0.89 squirrels/ha and the mean area occupied by males was larger during the winter mating period, decreasing gradually during subsequent seasons. The diurnal activity of S. ingrami exhibited bimodal curves in all seasons, with one peak in the morning and another in the afternoon. During the winter, the morning peak was greater in amplitude than during the other seasons. In the spring and summer, a marked increase in the activity of the squirrels during the hottest hours occurred. The morning peak of activity occurred earlier in the spring and summer and later in the autumn and winter. The daily time spent inrest, displacement, feeding, and maintenance showed seasonal variation similar to that shown by other sciurids.
Comparison of fecundity-length-latitude relationships between nonanadromous (kokanee) and anadromous sockeye salmon (Oncorhynchus nerka)
Authors: McGurk M D
Published: April 2011

This study compared fecundity-length-latitude relationships between 25 kokanee populations (15 natural and 10 introduced) and 48 sockeye salmon populations. Significant differences confirmed the hypothesis that the two Oncorhynchus nerka variants follow different reproductive strategies: (i) fecundity is more highly correlated with length for kokanee than for sockeye salmon; (ii) kokanee have higher fecundity-length regression slopes and lower intercepts than sockeye salmon; (iii) kokanee populations share a common fecundity-length regression slope, but sockeye salmon populations do not; and (iv) average lengths and fecundities of kokanee decrease with increasing latitude, but those of sockeye salmon do not. The first three findings confirm that kokanee maintain a constant egg size while increasing egg number with increasing body size but that sockeye salmon increase both egg number and egg size with increasing body size. Kokanee egg sizes may be less variable than those of sockeye salmon because kokanee have lower and less variable energetic costs of spawning migration and tend to use spawning gravel with smaller and less variable particle sizes. Latitudinal clines in kokanee length and fecundity may reflect latitudinal gradients in temperature and duration of the growing season. Such environmental gradients may explain why kokanee populations are rarely found as far north as Alaska.
Grey seal, Halichoerus grypus, habitat selection around haulout sites in the Baltic Sea: bathymetry or central-place foraging?
Authors: Sjöberg M , Ball John P
Published: April 2011

We investigated habitat selection by grey seals, Halichoerus grypus, around haulouts in the Baltic Sea. Home ranges (95% fixed kernel) varied in size from 1088 to 6400 km2. Observed habitat use was tested against the circular home range predicted from a simple central-place model. The overlap between the home ranges predicted by this simple model and actually exhibited by the seals was <70% for 9 of 11 seals. Furthermore, the depth distributions of the utilised areas were significantly different from that available in the circular home range for all 11 seals. Seals selected depths of 11-40 m and avoided areas >51 m deep. Ten of the 11 seals used areas within a 50-km radius around the haulout site for more than 75% of the time. Thus, in spite of their mobility and the availability of many islands, seals usually remained in the vicinity of a specific haulout site for extended periods. The seals did not use the habitat around the haulout site as predicted by the simple central-place model, but selected habitat according to bathymetric characteristics (e.g., water depth). Detection of these relatively small but heavily used home ranges around haulout sites may be of assistance in management plans in order to reduce the growing number of seal-fisheries conflicts.
Seasonal home range size and philopatry in two northern white-tailed deer populations
Authors: Lesage Louis , Crête Michel , Huot Jean , Dumont A , Ouellet Jean-Pierre
Published: April 2011

From 1994 to 1997, we compared summer and winter space utilisation by two white-tailed deer (Odocoileus virginianus) populations wintering in adjacent areas in southeastern Quebec characterised by deep snow cover. One population lived at low density (10 deer/km2) with access to abundant forage in winter (127 000 twigs/ha), whereas for the other, high-density population (20 deer/km2), forage availability was reduced (68 000 twigs/ha). Because of intraspecific competition for resources, we predicted that deer in the high-density population would have smaller home ranges, would exhibit greater philopatry, and would be more likely to disperse. Deer from both populations occupied summer home ranges that were similar in size (1182 ha for adult males; 1102 ha for adult females; 6033 ha for yearling males; 2528 ha for yearling females) but much larger than home ranges observed elsewhere in North America. The high-density population showed a higher level of philopatry than the low-density population during winter but not during summer. Most deer remained migratory during the study (n = 93) but 4 of the 5 that dispersed were from the high-density population. We speculate on the ability of white-tailed deer populations facing severe winters to adapt to using large home ranges in summer. Our results shed light on how wintering areas appear and expand.
Parental care in Sphaerium striatinum Lamarck: evidence for retention of competent offspring
Authors: Beekey Mark A , Karlson Ronald H , Greenberg Alyse R
Published: April 2011

The timing of offspring release is a fundamental turning point in the life history of any organism. It represents the end to many of the most costly forms of parental care (e.g., provisioning of nutrients for developing eggs and zygotes) and the beginning of an independent life for the offspring. Generally temporal variation in this event is attributed to a variety of physiological and evolutionary trade-offs. Here we examine the retention of offspring in the freshwater clam Sphaerium striatinum Lamarck. Brooded offspring are typically not released into the environment until they are 4.0 mm shell length (SL). We provide evidence that offspring as small as 2.0 mm SL are competent to process particles and produce both fecal and pseudofecal material. Furthermore, such small clams are shown to experience higher mortality than larger individuals once they are removed from brood pouches. Hence, the retention of competent offspring within brood pouches represents a form of extended parental care.
Problems utilizing an enzyme sensitive site assay for photorepair of exogenous DNA with cell-free extracts made from amphibian embryos
Authors: Smith M Alex
Published: April 2011

Attempts were made to assay the ultraviolet-B (UVB) damage repair ability of seven Ontario amphibian species using an enzyme sensitive site restriction-enzyme (ESS) assay. Cell-free protein extracts of amphibian eggs caused the degradation of even high (9 mg/mL) exogenous DNA concentrations. This type of signal loss is characteristic of nuclease digestion. High endogenous concentrations of amphibian nucleases appear to preclude the use of plasmid DNA-ESS assays to determine the UVB damage repair abilities of amphibian eggs. Proper estimation of amphibian ultraviolet damage repair characteristics, using any assay, is reliant upon the generation of cell-free protein extracts created from amphibian embryos covered in protective jelly. The process of releasing the embryo from the glycoprotein-carbohydrate jelly ("dejellying") is achieved by shaking the jelly mass in a solution of 2% L-cysteine. Equivalent exposure to 2% L-cysteine results in a radically different end product with different amphibian taxa. These previously unreported phenomena have important implications for the production, standardization, and reporting of amphibian photorepair data.
Shattering the folklore: black flies do not pollinate sweet lowbush blueberry
Authors: Hunter Fiona F , Burgin Steven G , Woodhouse Allan
Published: April 2011

It is often said that on the Canadian Shield, black flies pollinate the sweet lowbush blueberry, because years with high black fly populations also tend to be those with large blueberry crops. This folklore has never been tested experimentally. Here we report on research designed to test whether or not black flies can act as pollinators for two species of ericaceous plants, sweet lowbush blueberry (Vaccinium angustifolium) and leatherleaf (Chamaedaphne calyculata). In enclosures, black flies may assist in leatherleaf pollination but there is no evidence that they increase fruit set in sweet lowbush blueberry. However, we do not exclude the possibility that in the wild, they act as opportunistic nectar thieves of sweet lowbush blueberry.
Microhabitat utilisation, home ranges, and movement patterns of the collared lemming (Dicrostonyx groenlandicus) in the central Canadian Arctic
Authors: Predavec Martin , Krebs Charles J
Published: April 2011

We investigated patterns of home ranges, movements, and microhabitat use of the collared lemming (Dicrostonyx groenlandicus) on Kent Peninsula, Northwest Territories. Eleven animals were fitted with radio collars and intensively radio-tracked for 2 months. Males and females differed in their home ranges and movement patterns. Males moved, on average, 47.4 m and females 10.5 m in a 2-h period. Corresponding to the larger movements, males had larger home ranges than did females and the degree of overlap was greater in males. In both sexes activity was centred on burrows, but this was more evident in females. Collared lemmings differentially used available microhabitats, preferring areas with larger hummocks, a larger number of burrows, and greater cover of Salix lanata. It is suggested that this pattern of microhabitat use is related to reducing detection and capture by predators. Collared lemmings appear to be highly conservative in their patterns of habitat use and home ranges across their distribution.
Effet de la lumière et de la température sur le rythme d'activité de la marmotte alpine (Marmota marmota Linné, 1758) en milieu naturel
Authors: Semenov Youri , Ramousse Raymond , Berre Michel Le
Published: April 2011

External daily activity was studied in the alpine marmot (Marmota marmota Linné, 1758) in its natural environment in relation to the position of the sun, ambient temperature, and food accessibility. At low temperatures, daily activity starts only when the sun reaches 30° or more above the horizon. During temperate periods, external daily activity is closely synchronized with the height of the sun (16°-17° above the horizon). However, on hot days the duration of surface activity of alpine marmots at the end of the day could be explained by the postponement of feeding when high and uncomfortable midday temperatures limit food accessibility. Our observations under natural conditions seem to indicate that several factors are involved in the synchronization of nyctemeral activity in the alpine marmot. The cycle of light, expressed as the height of the sun above the horizon, is the most important. However, marmots show different responses to light in the morning and at night. These results corroborate the circadian rhythm model with two oscillators.
Prolonged winter undernutrition and the interpretation of urinary allantoin:creatinine ratios in white-tailed deer
Authors: DelGiudice Glenn D , Kerr Ken D , Mech L David , Seal Ulysses S
Published: April 2011

The urinary allantoin:creatinine (A:C) ratio (expressed in micromoles of allantoin to micromoles of creatinine) has shown potential as an index of recent winter energy intake in preliminary controlled studies of elk (Cervus elaphus) involving mild condition deterioration (up to 11% loss of body mass). To ensure reliable nutritional assessments of free-ranging cervids by measuring A:C ratios of urine in snow, it is essential to extend this work. We assessed the effect of moderate and severe winter nutritional restriction on urinary A:C ratios of captive white-tailed deer (Odocoileus virginianus) that lost up to 32% body mass and related these ratios to metabolizable energy intake (MEI), body-mass loss, and other reported nutritional indicators. Deer in the control group were fed a low-protein, low-energy diet ad libitum, whereas deer in the treatment group were fed restricted amounts of the same diet. MEI was below the winter maintenance requirement for all deer, but was lower (P = 0.029) in treatment deer than in control deer. Percent body-mass loss differed between the two groups as the study progressed, and represented the full range of physiological tolerance (0-32% loss). Mean A:C ratios of control deer, which lost up to 17.4% body mass, showed a slight increasing (P = 0.086) trend, whereas initially similar A:C ratios of severely restricted deer increased (P = 0.0002) markedly by the eighth week (0.52 vs. 0.09 µmol:µmol). The urinary A:C ratio was not related (P = 0.839) to recent (2 days prior to urine sampling) MEI, but there was a marginally significant relation (r2= 0.42, P = 0.110) between the A:C ratio and cumulative percent mass loss. The urinary A:C ratio was directly related to urinary urea nitrogen:creatinine (r2= 0.59, P < 0.0001) and 3-methylhistidine:creatinine (r2= 0.43, P < 0.0001) ratios. This study confirms that elevated and increasing A:C ratios may be due either to increasing energy intake or to accelerated tissue catabolism and increased endogenous contributions to urinary allantoin excretion.
Spatial-use patterns, movements, and interactions among adult coyotes in central Mississippi
Authors: Chamberlain Michael J , Lovell Charles D , Leopold Bruce D
Published: April 2011

Recently, coyotes (Canis latrans) have expanded their range to include most areas of the southeastern United States. However, most research on coyotes has been conducted in western and northern regions of North America. We radio-monitored 38 adult coyotes from 1993 to 1997 in central Mississippi. Home-range sizes (P = 0.681) and core-area (area of concentrated use) sizes (P = 0.736) were similar across seasons, but females maintained larger home ranges (P = 0.006) and core areas (P < 0.001) than males. Male-male, female-female, and male-female home-range overlap was greatest during whelping and pup rearing. Except for mated pairs, core-area overlap was negligible across all seasons for adults maintaining neighboring home ranges. Coyote habitat selection varied across spatial scales, though selection was similar between males and females at all scales. Coyote movement rates differed (P < 0.001) temporally, being highest during nocturnal periods. Overall, the highest movement rates for the monitored population were observed for females during summer. Two males and 2 females were suspected of forming pair bonds and frequently traveled together within shared home ranges, as did 2 adult males. Our data indicate that interactions among individual adults are influenced by sex, as most confirmed instances of direct contact occurred between pairs or suspected social groups. In our study area, neighboring adult coyotes exhibited territoriality at the core-area level.
The stability of vertical distribution profiles of insects in air layers near the ground
Authors: Boiteau Gilles , Osborn Walter PL , Xiong Xingyao , Bousquet Yves
Published: April 2011

The vertical distribution of insect orders, families, and species captured over 10 elevations from the ground to 15 m over 4 years in a potato agro-ecosystem differed considerably within and between taxa. Regression slopes representing these aerial profiles remained similar over the 4 years of the study for orders Thysanoptera, Neuroptera, and Psocoptera, changed considerably for Hemiptera, Homoptera and Ephemeroptera, and were statistically non-homogeneous for Coleoptera, Hymenoptera, Diptera, Lepidoptera, Trichoptera, and Plecoptera. The slopes of the aerial profiles for families remained similar over the years for Carabidae and Elateridae, changed for Staphylinidae, Meloidae, and Scarabeidae, but were statistically non-homogeneous for Coccinellidae, Miridae, and Aphididae. The slopes of the aerial profiles for insect species were similar across years for Coccinella septempunctata L., Melanotus similis (Kirby), and Anatis mali Say, changed for Pyrrhalta luteola (Mull.), Ctenicera pulchra LeConte, Ctenicera tarsalis Melsheimer, Coccinella trifasciata perplexa Muls., Lygus lineolaris (P. de B.), Ctenicera appropinquans Randall, Apis mellifera L., and Adalia bipunctata (L.), but were significantly non-homogeneous only for Hippodamia convergens G.-M. Although most profiles obtained for insect orders in this study were remarkably similar to those reported in the literature, the level of between-year variation at our study site suggests that there is considerable overlap between profiles at all taxon levels. Vertical aerial profiles cannot be considered sufficiently characteristic of the species, family, or order across years for use as indicators of change in biodiversity. The impact of these results on insect monitoring are discussed.
Site familiarity affects antipredator behavior of the amphisbaenianBlanus cinereus
Authors: López Pilar , Martín José , Barbosa Andrés
Published: April 2011

Morphological adaptations of amphisbaenians to fossorial life might affect their antipredator-behavior decisions. Amphisbaenians exposed on the soil surface by a predator can escape by burrowing immediately or by using alternative defensive behaviors on the soil surface, and should decide where to burrow in order to return to their home range. We simulated in the laboratory predatory attacks toward individual amphisbaenians (Blanus cinereus), and examined whether their antipredator and burrowing responses were affected by site familiarity (familiar versus unfamiliar substrate) and their internal state (i.e., body temperature and associated burrowing performance). Amphisbaenians showed significantly longer episodes of alternative antipredator behaviors on the soil surface (coiling and still) when the temperature was low. Before starting to burrow in unfamiliar substrates, individuals emitted numerous tongue flicks and moved for significantly longer periods of time than when on familiar substrates, independently of temperature. In contrast, in their own cages, with familiar substrates, amphisbaenians performed only a few tongue flicks before starting to burrow. Subsequently, the time spent burrowing was significantly longer when the temperature was low or amphisbaenians were on an unfamiliar substrate. These results suggest that amphisbaenians are able to recognize their own home range by chemosensory cues and that they are able to use this information when deciding where to burrow to escape from potential predators.
Modeling the role of songbirds and rodents in the ecology of Lyme disease
Authors: Giardina Antonia R , Schmidt Kenneth A , Schauber Eric M , Ostfeld Richard S
Published: April 2011

Small rodents such as the white-footed mouse (Peromyscus leucopus) and the eastern chipmunk (Tamias striatus) efficiently transmit Borrelia burgdorferi, the etiologic agent of Lyme disease, to feeding ticks, whereas other hosts of ticks are less efficient reservoirs of B. burgdorferi. We examined the roles of ground-foraging and ground-nesting songbirds as alternative hosts for ticks, focusing on their potential to dilute the infection prevalence of ticks (Ixodes scapularis, the black-legged tick) with B. burgdorferi. We developed a mathematical model based on the relative use by ticks of rodent and bird hosts across varying host densities. We parameterized the model for sites in southeastern New York State using original data and for the northeastern United States using published values. Our results indicate that American robins (Turdus migratorius), ovenbirds (Seiurus aurocapillus), veeries (Catharus fuscescens), and wood thrushes (Hylocichla mustelina) have a low capacity to dilute the prevalence of tick infection, particularly when rodents are at moderate to high densities. We attribute this result to low use by ticks of birds and a low density of birds relative to that of rodents. Only when rodents constitute less than ca. 10-20% of the combined rodent and songbird host community are birds capable of substantially reducing the infection prevalence of ticks. In years or habitat types in which the density of rodents is low but that of ground-dwelling songbirds is high, the risk of human exposure to Lyme disease may reduced because birds dilute the infection prevalence of tick vectors.
Dive behaviour, foraging locations, and maternal-attendance patterns of Australian fur seals (Arctocephalus pusillus doriferus)
Authors: Arnould John PY , Hindell Mark A
Published: April 2011

The dive behaviour, foraging locations, and colony-attendance patterns of female Australian fur seals (Arctocephalus pusillus doriferus) from Kanowna Island (39°10'S, 146°18'E) in Bass Strait, southeastern Australia, were determined throughout lactation during 19971999. Foraging-trip durations increased as lactation progressed, being shortest in summer (3.71 ± 0.24 days; mean ± 1 SE) and longest in winter (6.77 ± 0.57 days, P < 0.05), but maternal-attendance periods did not differ in duration (1.70 ± 0.10 days, P > 0.5). Individual mean attendance periods and trip durations were positively correlated (r2 = 0.21, P < 0.005). Diving commenced shortly after seals left the colony (2.6 ± 0.4 h), was continuous for long periods (up to 36 h), occurred mostly during daylight hours, and lacked regular diel variation in depth. The majority of dives (78%) were typically U-shaped and reached depths corresponding to the prevailing depths in Bass Strait (6585 m), indicating that these animals forage mostly on the benthos of the shallow continental shelf in this region. Such behaviour is unusual for fur seals but is reminiscent of that of some sea lion species. Mean dive durations varied between 2.0 and 3.7 min (maximum 8.9 min) and the theoretical aerobic dive limit (3.914.26 min) was exceeded on 17.3% of dives. Dive frequency (8.3 ± 0.6/h) and the proportion of time at sea spent diving (40.7 ± 2.1%) were weakly negatively related to the duration of the foraging trip (r2 = 0.07, P < 0.004, and r2 = 0.13, P < 0.0001, respectively). Data from at-sea locations showed that lactating females forage almost exclusively within Bass Strait during all seasons.
Comparative survey of early embryogenesis of Secernentea (Nematoda), with phylogenetic implications
Authors: Dolinski C , Baldwin J G , Thomas W K
Published: April 2011

Insight into the evolution of class Secernentea (Nematoda) for the purpose of providing a phylogenetic context for the model Caenorhabditis elegans is being gained from the use of molecular character sets. Such phylogenies provide a framework for mapping the evolution of diversity in some early-development characters for 70 species and 19 families of Secernentea. These characters include (i) whether AB and P1 blastomeres initially develop at the same (synchronous) or different (asynchronous) rates, (ii) whether AB and P1 are initially aligned along the linear axis of the embryo (tandem pattern) or obliquely (rhomboidal pattern), and (iii) whether the founder germ cell, P4, is established early, i.e., by the sixth cleavage, or later. Evolutionary polarity of characters was evaluated through outgroup comparisons. From our data the following inferences are made. The derived character, late establishment of P4, evolved primarily in the ancestor of the monophyletic groups Diplogastrina, Rhabditina, and Panagrolaimidae. Asynchronous development is convergent, defining one clade of Tylenchina as well as Cephalobina, and also arising independently in Aphelenchina. The rhomboidal embryo is ancestral to the tandem-pattern embryo that defines a second clade of Tylenchina. Early-embryo characters are congruent with the polyphyly of Cephalobina and Aphelenchina, as has been demonstrated by molecular phylogenies. Many aspects of early embryogenesis, rather than being highly conserved, evolve at a rate appropriate to defining taxa within Secernentea.
Application of microsatellite DNA markers to discriminate between maternal and genetic effects on scalation and behavior in multiply-sired garter snake litters
Authors: King Richard B , Milstead W Bryan , Gibbs H Lisle , Prosser Melanie R , Burghardt Gordon M , McCracken Gary F
Published: April 2011

Incomplete knowledge of pedigrees sometimes limits the methods of estimating quantitative genetic parameters (heritability, genetic correlation) in nature and may result in estimates that are inflated by nongenetic sources of variation. North American garter snakes and their allies provide a model system for investigating evolutionary quantitative genetics, but estimates of quantitative genetic parameters in these snakes are mostly based on offspring-dam regression and full-sib analysis, methods that fail to discriminate between maternal genetic, maternal environmental, and direct genetic effects on traits of interest. Using data from the garter snake Thamnophis sirtalis, we demonstrate that microsatellite DNA markers can be used to identify full-sib sireships within litters in species that produce large numbers of offspring and in which multiple paternity is common. This allows estimation of quantitative genetic parameters using a maternal half-sib analysis in which sires are nested within dams. Six microsatellite DNA loci were scored for four wild-caught dams and their 73 offspring and revealed two full-sib sireships within each litter. Maternal half-sib analyses of scalation and behavior suggest that heritability may be lower and maternal effects larger than was previously thought.
Increased prevalence of bot flies (Cuterebra fontinella) on white-footed mice (Peromyscus leucopus) near forest edges
Authors: Wolf Mosheh , Batzli George O
Published: April 2011

Several studies have suggested that forest edge is preferred habitat for white-footed mice (Peromyscus leucopus). Because previous research has shown that parasitism by bot flies (Cuterebra fontinella) is higher in open areas than in woodlands, lower rates of infestation at woodland edges could partly explain the greater preference for woodland edges by the mice. We recorded the prevalence and load of bot fly larvae in mice trapped along edge-to-interior gradients in four forested areas in east-central Illinois. At all sites the prevalence of bot flies (the proportion of infected adult mice) was greatest near the edge (less than 50 m from the woodland margin), which should reduce, not improve, the quality of edge microhabitats. Mating bot flies tend to congregate in open areas, and the higher prevalence of parasitism by bot flies near the forest edge may reflect the greater penetration of light there than in the interior.
Blood metabolites as indicators of nutrient utilization in fasting, lactating phocid seals: does depletion of nutrient reserves terminate lactation?
Authors: Mellish J E , Iverson S J
Published: April 2011

Metabolites of lipid (free fatty acids (FFA) and β-hydroxybutyrate (βHBA)) and protein (blood urea nitrogen (BUN)) oxidation were measured during lactation in 18 female grey seals (Halichoerus grypus) and 6 female hooded seals (Cystophora cristata) as indicators of nutrient depletion and possible cues for pup weaning. FFA levels were high during lactation in both grey seals (51.2 ± 2.3 mg·dL-1) and hooded seals (67.0 ± 8.1 mg·dL-1), and levels were primarily related to the rapid lipid mobilization required for their high respective milk-fat outputs (P = 0.002). βHBA concentrations were negligible throughout lactation in both species (0.30 ± 0.14 and 0.03 ± 0.01 mg·dL-1, respectively). Grey seals exhibited a decrease in BUN levels over the course of lactation (i.e., days 0-15, 39.3 ± 1.8 - 23.5 ± 3.3 mg·dL-1, P < 0.001), which suggests protein sparing despite the added energetic cost of milk production over the 16-d lactation period. In contrast, hooded seals showed higher levels and no change in BUN levels (i.e., days 0-3, 43.2 ± 2.1 - 45.8 ± 2.1 mg·dL-1, P > 0.3), suggesting that there is less need to spare protein in a species which lactates for only 3.6 d. Females of both species weaned their pups before entering stage III fasting, therefore metabolite levels do not appear to be a physiological cue for weaning.