Changes in body condition of hibernating bats support the thrifty female hypothesis and predict consequences for populations with white-nose syndrome

White-nose syndrome (WNS) is a new disease of bats that has devastated populations in eastern North America. Infection with the fungus, Geomyces destructans, is thought to increase the time bats spend out of torpor during hibernation, leading to starvation. Little is known about hibernation in healthy, free-ranging bats and more data are needed to help predict consequences of WNS. Trade-offs presumably exist between the energetic benefits and physiological/ecological costs of torpor, leading to the prediction that the relative importance of spring energy reserves should affect an individual''s use of torpor and depletion of energy reserves during winter. Myotis lucifugus mate during fall and winter but females do not become pregnant until after spring emergence. Thus, female reproductive success depends on spring fat reserves while male reproductive success does not. Consequently, females should be “thrifty” in their use of fat compared to males. We measured body condition index (BCI; mass/forearm length) of 432 M. lucifugus in Manitoba, Canada during the winter of 2009/2010. Bats were captured during the fall mating period (n = 200), early hibernation (n = 125), and late hibernation (n = 128). Adult females entered hibernation with greater fat reserves and consumed those reserves more slowly than adult males and young of the year. Consequently, adult females may be more likely than males or young of the year to survive the disruption of energy balance associated with WNS, although surviving females may not have sufficient reserves to support reproduction.     

Changes in various plasma lipid components, glucose, and insulin in Spermophilus lateralis during hibernation

This study evaluated fat mobilization as related to gluconeogenesis in two age groups of hibernating golden-mantled ground squirrels (Spermophilus lateralis). Our experimental group consisted of a total of 16 male and 15 female squirrels. Plasma samples were collected from selected animals being killed weekly from January to March, and the concentration of triglycerides, glycerol (GY), free fatty acids (FFA), total cholesterol, lipase activity, glucose, and insulin, were determined by biochemical assays and radioimmunoassay. Our results showed a mean FFA/GY ratio of five, which was higher than the predicted value of three, suggesting a significant depletion of GY and an enhanced rate of gluconeogenesis via GY to maintain glucose homeostasis in the hibernating animals. The factor of age did not significantly affect plasma lipid components. However, in the male group, plasma glucose levels were significantly higher for adults than for juveniles. Overall, females had significantly higher plasma glucose levels than males (150 ± 11 vs. 110 ± 8 mg%, P < 0.05). In the adult group, a gender influence was also seen on plasma insulin levels, with females' being higher than males' (66 ± 13 vs. 25 ± 3 μIU/ml, P < 0.01). We suggest that during hibernation, female squirrels may have a higher rate of lipolysis and gluconeogenesis along with a lower glucose utilization than their male counterparts. Additionally, adult females may exhibit a higher peripheral insulin resistance during hibernation than adult males, a possibility which merits further study.     

Three digestive tract endocrine peptides and the circannual cycle of body weight in Spermophilus lateralis

• 1.1. Thirty-one male golden-mantled ground squirrels were divided into four physiological groups: low wt summer, medium wt summer, high wt summer and hibernation period. A second group of 10 females was divided into two groups: hibernation period at low T_b and hibernation period during a periodic arousal.
• 2.2. Blood serum, pancreas and antral stomach region were collected from each animal.
• 3.3. The serum was analysed by radioimmunoassay for pancreatic polypeptide immunoreactivity, the pancreas for pancreatic polypeptide and somatostatin immunoreactivity and the antral region of the stomach for gastrin immunoreactivity.
• 4.4. Significant between-stage differences (P < 0.05) were found in serum pancreatic polypeptide concentration and in pancreatic somatostatin content.

     

Juvenile hormone-dependent vitellogenin synthesis in Locusta migratoria fat body: Inducibility related to sex and stage

Juvenile hormone (JH)-dependent vitellogenin (Vg) synthesis in the fat body of Locusta migratoria is normally limited to sexually mature adult females. As a step toward examining the basis of this limitation, we have tested female and male locusts in a series of stages after the third larval molt for inducibility of Vg synthesis by the synthetic JH analog, methoprene. We find that in the fourth and fifth larval instars fat body of both sexes can be induced to produce Vg, but in the adult stage females respond strongly while no more than trace amounts can be induced in males. Quantitative assays show relative responsiveness in the order: adult female > fifth instar female > fifth instar male ? adult male. During the fifth instar of both sexes, maximal vitellogenic response was obtained in midinstar. After the larval-adult ecdysis, female fat body was unresponsive during the first 4 days, then responsiveness increased and by Day 8 after ecdysis fat bodies were fully as competent to produce Vg as at Day 14, the usual maximum of the first vitellogenic cycle due to endogenous JH. Larval and adult female fat bodies implanted into male larvae are competent for Vg synthesis after metamorphosis, so that the differences between adult male and female cannot be imposed by the male milieu intérieur during the larval-adult molt. In male and female precocious adults, produced by treatment of fourth instars with precocene, fat body responded to methoprene as in normal adults. We conclude that factors intrinsic to the fat body cells, determined early in development, are responsible for differential gene programing in males and females, which is partially expressed by the fifth instar but fully manifest only after a molt in the absence of JH.     

Comparison of the frequency of the growth hormone pseudogene between juvenile and adult female masu salmon Oncorhynchus masou

The proportions of individual masu salmon Oncorhynchus masou whose genotypic and phenotypic sex differed were compared among juvenile and adult fish in three rivers, and genotypically male but phenotypically female individuals were observed 6–16% more often among adults than among juveniles. This suggests that during the transition from juvenile to adult, survival rates of genotypically male but phenotypically female individuals are higher than those of normal females. In contrast, genotypically female but phenotypically male individuals were only found in the juvenile period, which suggests that they exhibit a decreased survival rate in comparison with normal males.     

Hibernation in the mountain pygmy possum Burramys parvus (Marsupialia)

Mountain pygmy possums Burramys parvus (40 g) disappear from their Mt. Kosciusko boulder fields from May to October/November and it is assumed that they hibernate during this time. However, laboratory studies did not observe the characteristic hibernation pattern of placentals, which, throughout the hibernation season, show long bouts of torpor (several days to weeks) that are interrupted by short (< 1 day) normothermic periods. We investigated the pattern of hibernation in juvenile (N = 8) and adult (N = 8) male and female B. parvus in the laboratory at an air temperature that was similar to that in the field during winter. Adults commenced hibernation earlier and hibernated longer (about seven months) than juveniles (about five months). All adult individuals hibernated whereas only six of the eight juveniles did so. Hibernating animals showed distinct seasonal changes in the duration of torpor bouts. Torpor bouts were short (about five days) at the beginning, long (12–20 days) during the middle, and short again at the end of the hibernation season. Normothermic periods were usually shorter than one day. The pattern of the seasonal change of torpor bout duration differed between juveniles and adults and between sexes. Body temperature during mid-hibernation was regulated at about 2 ° c in females and 3 ° C in males and the metabolic rate was similar to that of hibernating placentals.     

You Are What You Eat: Food Limitation Affects Reproductive Fitness in a Sexually Cannibalistic Praying Mantid

Resource limitation during the juvenile stages frequently results in developmental delays and reduced size at maturity, and dietary restriction during adulthood can affect longevity and reproductive output. Variation in food intake can also result in alteration to the normal pattern of resource allocation among body parts or life-history stages. My primary aim in this study was to determine how varying juvenile and/or adult feeding regimes affect particular female and male traits in the sexually cannibalistic praying mantid Pseudomantis albofimbriata. Praying mantids are sit-and-wait predators whose resource intake can vary dramatically depending on environmental conditions within and across seasons, making them useful for studying the effects of feeding regime on various facets of reproductive fitness. In this study, there was a significant trend/difference in development and morphology for males and females as a result of juvenile feeding treatment, however, its effect on the fitness components measured for males was much greater than on those measured for females. Food-limited males were less likely to find a female during field enclosure experiments and smaller males were slower at finding a female in field-based experiments, providing some of the first empirical evidence of a large male size advantage for scrambling males. Only adult food limitation affected female fecundity, and the ability of a female to chemically attract males was also most notably affected by adult feeding regime (although juvenile food limitation did play a role). Furthermore, the significant difference/trend in all male traits and the lack of difference in male trait ratios between treatments suggests a proportional distribution of resources and, therefore, no trait conservation by food-limited males. This study provides evidence that males and females are under different selective pressures with respect to resource acquisition and is also one of very few to show an effect of juvenile food quantity on adult reproductive fitness in a hemimetabolous insect.     

Overwintering of European hedgehogs<Emphasis Type="Italic">Erinaceus europaeus</Emphasis> in a Danish rural area

Ten radio-tagged hedgehogsErinaceus europaeus (Linnaeus, 1758) were monitored during the winter of 2001/2002 in a Danish rural area. The study was aimed at measuring parameters essential for hibernation success and the fate of the mainly juvenile hedgehogs being recorded. The average duration of hibernation was found to be 179 days for juveniles (n=6) and 198 days for adult females (n=3). The most often used nesting habitat types were forested areas (55%). The hedgehogs typically used 2 nests during the hibernation period, but up to 4 different nests used by one hedgehog were found. Time spent in different nests varied considerably (6-187 days). The average weight loss during hibernation was 22.1% for juveniles and 30.2% for adult females. Minimum body mass sufficient for survival was registered to be 513 g prior to hibernation. Nine of the hedgehogs survived until departure from their hibernacula, while the fate of 1 juvenile is unknown. Indication was thus found that the minimum weight required to survive the winter has previously been overestimated.     

Male contest investment changes with male body size but not female quality in the spider Nephila clavipes

Animals use rules to adjust their level of investment in a contest. We evaluate male strategies during contests over females in the golden orb-web spider Nephila clavipes. We tested whether male behaviour changes with female value, and found that contests were similar in intensity and outcome whether the female was a juvenile or adult, virgin or non-virgin, or whether one male had invested sperm in the female. We found evidence that males use a self-assessment strategy when deciding to withdraw from a contest. Loser body size and contestant size difference were correlated with a higher frequency of contest escalation, and fights involving two large males were more likely to escalate than a fight in which one male was small. A multiple regression showed that loser body size had a stronger effect on contest escalation than contestant body size difference. More importantly, the size of the winning male had no effect on contest escalation, a key prediction of a self-assessment strategy. In N. clavipes, body size is the primary factor that determines the outcome of male contests, and males do not appear to assess their opponent or the quality of the resource when deciding to withdraw from the fight.     

Lipid synthesis and deposition by adult Richardson's ground squirrels in the natural environment

Summary Adult male Richardson's ground squirrels,Spermophilus richardsonii, were estimated to have emerged from hibernation in late February to early March, and adult females in mid to late March. Half of the females trapped in late March were not pregnant, as against 10% after that time. In late March males and all females had similar WAT (white adipose tissue) deposits. Between late March and early June, WAT deposits in males increased from 14 g to 64 g (a rate of 5.6 g per week). In non-parous females WAT deposits increased from 13 g to 48 g from late March to late May (4.2 g per week). Fat deposits decreased during lactation but thereafter increased from 8 g to 29 g (a rate of 6.0 g per week) between early May and early June. In males the rate of fatty acid synthesis in BAT (brown adipose tissue), liver and WAT did not change from late March to late May, and rates in the corresponding tissues of non-pregnant females were similar to those in males. Fatty acid synthesis decreased during late pregnancy and lactation. After lactation, the rate of fatty acid synthesis in all tissues increased to that in males and non-pregnant females. Males initiated fattening 5–7 weeks earlier than females. It is concluded that compared with adult males, the later immergence of adult female Richardson's ground squirrels into hibernation is due primarily to later initiation of fattening and less to differences in rate of lipid synthesis after the reproductive period. Rates of fatty acid synthesis in liver and BAT were several times greater than that in WAT. The former tissues may contribute fatty acids for prehibernatory fattening.Abbreviations BAT brown adipose tissue - WAT white adipose tissue     

Production,maturity, reproductive cycle and fecundity of small-spotted catshark,Scyliorhinus canicula (Chondrichthyes: Scyliorhinidae) from the northern coast of Tunisia (Central Mediterranean)

Small-spotted catshark Scyliorhinus canicula (Linnaeus, 1758) is confronted since 2000 to a drastic decline of captures in Tunisian northern areas where it formerly was quantitatively and qualitatively very abundant. A study conducted in the area showed that males and females sexually matured between 400–478 mm and 364–471 mm total length (TL), respectively. The largest male and female were 521 mm and 531 mm TL, respectively and weighed 449 and 445.5 g, respectively. There was a not significant relationship total mass vs. TL between males and females. Conversely, the relationship of liver mass vs. TL significantly differed between sexes. Both HSI and GSI values did not present significant differences between males and females. There was a not significant relationship total mass vs. TL between males and females. Both male and female HSI reached high values in adults, significantly higher than those of sub-adults. Both male and female GSI values increased with TL of specimens; additionally, they showed significant differences between juveniles and sub-adults and also between sub-adults and adults. The OSI values were significantly different between juvenile and sub-adult females, and also between sub-adult and adult females. Monthly mean values of adult male and female HSI did not significantly vary throughout the year. Significant monthly changes were recorded in mean values of adult male however no significant changes were observed in monthly mean of GSI and OSI for adult females. Vitellogenic activity and production of egg cases permanently occurred throughout the year. The diameter of largest yolky oocytes ranged from 20.1 to 23.0 (mean = 21.43 ± 1.07) and weighed from 0.64 to 0.90 g (mean = 0.78 ± 0.09). Some measurements were taken on egg cases: length with horns ranged 42.5-55.7 mm with mean = 48.9 ± 2.9, width ranged 13.6–19.7 mm with mean = 16.50 ± 0.9, while the total mass of complete egg case ranged between 1.8 and 4.6 g, with mean = 2.4 ± 0.4. An annual fecundity estimation based on production of egg cases and oocytes during one year counted in adult females, enabled us to consider it between 40 and 240.     

Temporal Dynamics of the Cecal Gut Microbiota of Juvenile Arctic Ground Squirrels: a Strong Litter Effect across the First Active Season

Arctic ground squirrels (Urocitellus parryii) are active for a scant 3 to 5 months of the year. During the active season, adult squirrels compete for mates, reproduce, and fatten in preparation for hibernation, while juvenile squirrels, weaned in early July, must grow and acquire sufficient fat to survive their first hibernation season. During hibernation, the gut microbial community is altered in diversity, abundance, and activity. To date, no studies have examined the gut microbiota of hibernators across the truncated active season. We characterized trends in diversity (454 pyrosequencing), density (flow cytometry), viability (flow cytometry), and metabolism (short-chain fatty acid analysis) of the gut microbial community of juvenile arctic ground squirrels across their first active season at weaning and at 4, 6, 8, and 10 weeks postweaning. At 8 weeks postweaning, the mean bacterial density was significantly higher than that at weaning, and the mean percentage of live bacteria was significantly higher than that at either weaning or 4 weeks postweaning. No significant differences in microbial diversity, total short-chain fatty acid concentrations, or molar proportions of individual short-chain fatty acids were observed among sample periods. The level of variability in gut microbial diversity among squirrels was high across the active season but was most similar among littermates, except at weaning, indicating strong maternal or genetic influences across development. Our results indicate that genetic or maternal influences exert profound effects on the gut microbial community of juvenile arctic ground squirrels. We did not find a correlation between host adiposity and gut microbial diversity during prehibernation fattening, likely due to a high level of variability among squirrels.     

Despotism and risk of infanticide influence grizzly bear den-site selection

Given documented social dominance and intraspecific predation in bear populations, the ideal despotic distribution model and sex hypothesis of sexual segregation predict adult female grizzly bears (Ursus arctos) will avoid areas occupied by adult males to reduce risk of infanticide. Under ideal despotic distribution, juveniles should similarly avoid adult males to reduce predation risk. Den-site selection and use is an important component of grizzly bear ecology and may be influenced by multiple factors, including risk from conspecifics. To test the role of predation risk and the sex hypothesis of sexual segregation, we compared adult female (n = 142), adult male (n = 36), and juvenile (n = 35) den locations in Denali National Park and Preserve, Alaska, USA. We measured elevation, aspect, slope, and dominant land cover for each den site, and used maximum entropy modeling to determine which variables best predicted den sites. We identified the global model as the best-fitting model for adult female (area under curve (AUC) = 0.926) and elevation as the best predictive variable for adult male (AUC = 0.880) den sites. The model containing land cover and elevation best-predicted juvenile (AUC = 0.841) den sites. Adult females spatially segregated from adult males, with dens characterized by higher elevations ( = 1,412 m, SE = 52) and steeper slopes ( = 21.9°, SE = 1.1) than adult male (elevation:  = 1,209 m, SE = 76; slope:  = 15.6°, SE = 1.9) den sites. Juveniles used a broad range of landscape attributes but did not avoid adult male denning areas. Observed spatial segregation by adult females supports the sex hypothesis of sexual segregation and we suggest is a mechanism to reduce risk of infanticide. Den site selection of adult males is likely related to distribution of food resources during spring.     

Effects of food restriction across stages of juvenile and early adult development on body weight,survival and adult life history

Organisms have to allocate limited resources among multiple life‐history traits, which can result in physiological trade‐offs, and variation in environmental conditions experienced during ontogeny can influence reproduction later in life. Food restriction may lead to an adaptive reallocation of the limited resources among traits as a phenotypically plastic adjustment, or it can act as an overall constraint with detrimental effects throughout reproductive life. In this study, we investigated experimentally the effects of food restriction during different stages of the juvenile and early adult development on body weight, survival and reproductive success in females and males of the European earwig Forficula auricularia. Individuals either received limited or unlimited access to food across three different stages of development (fully crossed) allowing us to identify sensitive periods during development and to test both additive and interactive effects of food limitation across stages on development and reproduction. Food restriction during the early and late juvenile stage had additive negative effects on juvenile survival and adult body weight. With regard to reproductive success of females which produce up to two clutches in their lifetime, restriction specifically in the late juvenile stage led to smaller first and second clutch size, lower probability of second clutch production and reduced hatching success in the second clutch. Reproductive success of females was not significantly affected when their male mates experienced food restriction during their development. Our findings in general support the ‘silver‐spoon’ hypothesis in that food restriction during juvenile development poses constraints on development and reproduction throughout life.     

Schistosoma mansoni: Uptake in vitro and incorporation of adenine by adults

The rates of adenine uptake and incorporation into nucleic acids by adult male and female Schistosoma mansoni were determined during periods of up to 10 days in vitro, and comparisons were made between paired and separated worms. Adenine uptake by separated males and females exceeded that exhibited by equivalent paired worms. The rate of incorporation of adenine into nucleic acids was higher in separated females than in paired females. In contrast, the state of pairing had little effect on adenine incorporation by male S. mansoni. There was no correlation between rates of adenine uptake and incorporation and the reproductive activity of S. mansoni adults in vitro. Uptake and incorporation rates appeared to reflect the changing somatic requirements of both male and female worms.     

Dominance,grooming, and clasped-sleeping relationships among bonnet monkeys in India

Social relationships, including dominance, grooming, and clasped-sleeping, were studied in a troop of bonnet monkeys (Macaca radiata) at Dharwar, India, the study period lasting two months and a half. Three measurements, the peanut test, the drinking test, and the spatial distribution test, were used to analyze dominance relationships. The peanut test showed a straight linear ranking order among adult males and females; however, among females drinking and spatial distribution orders are slightly different from that of feeding (peanut test). Grooming was observed more frequently between adult female and adult female and was seldom observed between adult male and juvenile female or between juvenile male and juvenile female. Apparently all monkeys tend to groom with females. On the other hand, monkeys of the same sex tend to sleep with each other. It is clear that monkeys select their partners when they groom and sleep.     

菲菊头蝠冬眠期的精子储存

菲菊头蝠是分布于亚热带和热带的翼手目种类,在中国大陆南部和海南岛有广泛分布。为探讨热带菲菊头蝠是否具有冬眠期(12 月至翌年2 月)储精现象及生殖腺组织结构的变化,对海南岛的菲菊头蝠成年雄蝠和成年雌蝠生殖系统在冬眠期间的变化进行了石蜡切片观察。结果显示:成年雄蝠在冬眠期间附睾内储存大量精子,推测其储存时间超过2 个月;冬眠期间曲细精管横截面积、精子细胞数量和间质细胞数量在冬眠期逐月显著性减少,精原细胞和精母细胞的数量在12 月与翌年1 月间均无显著性变化,而在冬眠末期的2 月显著增多。在雌蝠子宫和卵巢内均未发现精子储存现象,但卵巢内具有初级卵泡和次级卵泡,雄蝠在冬眠期间曲细精管逐月萎缩,但生精上皮精母细胞的数量在冬眠末期明显上升。     

What is winter? Modeling spatial variation in bat host traits and hibernation and their implications for overwintering energetics

White‐nose syndrome (WNS) has decimated hibernating bat populations across eastern and central North America for over a decade. Disease severity is driven by the interaction between bat characteristics, the cold‐loving fungal agent, and the hibernation environment. While we further improve hibernation energetics models, we have yet to examine how spatial heterogeneity in host traits is linked to survival in this disease system. Here, we develop predictive spatial models of body mass for the little brown myotis (Myotis lucifugus) and reassess previous definitions of the duration of hibernation of this species. Using data from published literature, public databases, local experts, and our own fieldwork, we fit a series of generalized linear models with hypothesized abiotic drivers to create distribution‐wide predictions of prehibernation body fat and hibernation duration. Our results provide improved estimations of hibernation duration and identify a scaling relationship between body mass and body fat; this relationship allows for the first continuous estimates of prehibernation body mass and fat across the species'' distribution. We used these results to inform a hibernation energetic model to create spatially varying fat use estimates for M. lucifugus. These results predict WNS mortality of M. lucifugus populations in western North America may be comparable to the substantial die‐off observed in eastern and central populations.     

An ethogram of the liontail macaque (Macaca silenus) in captivity

Seventy hours of observation were gathered on a well-composed group of captive liontail macaques (1 adult male, 3 adult females, 1 sub-adult male, 1 sub-adult female, 2 juvenile males, 1 infant male, and 2 infant females caged together for more than five years). Their behaviors are described, defined and categorized, and comparisons are made with other Macaca species. Most of the behaviors observed tended to be similar to those of other congeneric macaques, with the exception of several variations typical for the liontail which are detailed. The behaviors and interactions of infant liontail monkeys are also discussed.     

Juvenile infection and male display: testing the bright male hypothesis across individual life histories

Current tests of the bright male hypothesis focus on assaysof adult disease resistance and their relation to male traitdevelopment and female choice. We suggest that if parasiteshave significant harmful effects on juvenile stages of a host,then females selecting males that effectively signal juvenileparasite resistance may gain a significant "good genes" benefit.Currently, there is no information on juvenile and adult infectionor resistance in the same male and whether adult male displayssignal juvenile parasite resistance. In the present study, wemeasure infection of the ectoparasitic louse, Myrsidea ptilonorhynchi,in individual male satin bowerbirds (Ptilonorhynchus violaceus)both as juveniles and nine or more years later as adults. Wetest hypotheses that examine the role of juvenile parasite infectionin mediating sexual selection. We found that (1) juvenile infectionis higher than adult infection in the same individuals, (2)adult males able to hold display sites have lower juvenile infection,and (3) juvenile and adult infection in the same individualsare not significantly correlated. In addition, comparisons amonga larger set of individuals from a single year show that bloodand ectoparasite infections are highly correlated, and bothdecrease with male age and are inversely related to male courtshipsuccess. These results, combined with the evidence that femalesmate exclusively with bower-holding males support the hypothesisthat females use adult male display traits to identify maleswith a high level of juvenile disease resistance. We suggestthat effective tests of the bright male hypothesis should include(1) assessment of infection resistance in both subadult andadult life history stages, (2) tests of whether differencesin age-specific resistance are indicated in adult male displays,and (3) tests to determine if females attend to these traitsin mate choice. Although these requirements increase the difficultyof testing the bright male hypothesis, they are necessary fora more accurate assessment of the effects of parasites on maledisplay and female choice.