Immunological identification of uncoupling protein in interscapular "brown" adipose tissue of suckling and adult pipistrelle bats (Pipistrellus pipistrellus).

1. Interscapular adipose tissue of suckling and adult pipistrelle bats was examined for the presence of the 32,000 Mr "uncoupling protein" diagnostic of brown adipose tissue. 2. Following separation by SDS-polyacrylamide gel electrophoresis, mitochondrial proteins were blotted onto nitrocellulose and probed for uncoupling protein with an anti-(ground squirrel uncoupling protein) serum. 3. Immunoreactivity consistent with the presence of uncoupling protein was found in all samples of adipose tissue mitochondria from both suckling and adult bats. 4. It is concluded that interscapular adipose tissue in pipistrelle bats exhibits the critical biochemical criterion for being designated functionally "brown".     

Impact of human disturbance,density, and environmental conditions on the survival probabilities of pipistrelle bat (Pipistrellus pipistrellus)

Natural and anthropogenic disturbances can strongly impact population dynamics of species and are often responsible for zoonotic emerging infectious diseases. However, long-term studies on the demographic consequences of human disturbances are unusual. We used 6 years (1995–2000) of mark-recapture data to investigate how climatic conditions, human disturbance and density affect sex- and age-specific apparent survival probabilities of the pipistrelle bat (Pipistrellus pipistrellus, Schreber 1774) in a maternity colony. Our study demonstrated that density played an important role in population dynamics of pipistrelle bat and that its effect differed with respect to age and sex. Notably, human disturbance caused a strong decline of adult female survival, suggesting that perturbations have important consequences in bat-colony dynamics. Juvenile female survival was negatively influenced by density, being considerably lower in high densities. In contrast, juvenile and adult males were apparently not affected as they had constant survival probabilities. Although climatic factors can markedly affect population dynamics of temperate insectivorous bats, in this study, the weather conditions did not influence the survival rates of pipistrelle bats. We provide the first report that demonstrates the density-dependent effect on bat survival. That is especially relevant to better understanding of the bat-population dynamics and to evaluate the consequences of human disturbance and their potential changes in the maternity colony structure.     

OBSERVATIONS ON NOCTULE BATS (NYCTALUS NOCTULA) CAPTURED WHILE FEEDING

In the summer and early autumn of 1960, 1961 and 1962, noctule bats flying low, taking house crickets as these flew from a municipal rubbish tip, were captured in mist nets, ringed, released and in many cases recaptured a number of times. The flying bats showed no fear of human beings or predatory birds and did not learn to avoid the net. In June and July of each year the majority of bats caught were adult females, the flying young of the year first appearing in August though some did not fly until September and October. Young males did not reach sexual maturity in the year of their birth, though five out of fourteen females recaptured at a year old did. There was a considerable movement of adult males in the late summer, adult bats being captured in approximately equal numbers of both sexes during August and September. In October the females seemed to disappear, the majority of the bats caught during that month being males: by November the crickets had ceased to fly and no more bats could be captured though a few wero still flying on warm nights. There was a marked difference in feeding behaviour over these three years, the bats concentrating more on crickets in 1960 than in 1961 and 1962. Though the differences are not statistically significant there were indications of an increase in body weight between July and October in the years when less cricket feeding was occurring. About 50 per cent of the females captured in each of the years 1960 and 1961 were recaptured feeding on the same site in the following year: the recovery rate of males was about 30 per cent in 1961, 60 per cent in 1962.     

The flight of pipistrelle bats Pipistrellus pipistrellus during pregnancy and lactation

A group of 20 pipistrelle bats were taken into captivity and allowed free flight and association within a flight room where they gave birth to and successfully reared 17 young. The flight of the females was recorded during pregnancy, early lactation and post-lactation by using stroboscopic stereophotogrammetry (153 flights reconstructed in total). During the investigation body mass was altering owing to reproductive condition, and changes in mass were recorded daily for all (adult and juvenile) bats during the entire study period, which lasted from two weeks before the last birth until release, when the oldest baby was 43 days old. All bats were individually marked, and detailed morphological measurements were made. Pregnant and post-lactating bats were heavier than lactating bats, which showed the lowest wingbeat frequencies. The flight speeds of pregnant, lactating and post-lactating bats showed no significant differences, and this may be because the pregnant bats appeared to have a wider scope for selecting flight speed than the other two reproductive groups, or than animals studied previously. The group of bats as a whole decreased flight speed (scaling as M^-043) and increased wingbeat frequency (scaling as M^0.58) as their mass increased. Wingbeat amplitude showed no relation to body mass, wing area or span, flight speed or frequency. A flight performance model applied to the experimental results and optimum flight conditions is used to predict cost of transport and mechanical power for steady flight, and equilibrium wingbeat amplitude which is compared with observations.     

The role of olfactory cues in mother–pup,groupmate, and sex recognition of lesser flat‐headed bats,Tylonycteris pachypus

Tylonycteris pachypus is a gregarious bat species with tens of individuals in a colony. The mechanisms by which mother bats recognize their pups and adult bats recognize each other are not clear. We hypothesized that such recognition is achieved by chemical discrimination and performed experiments to test the hypothesis. Results showed that mother bats were much more attracted to the scent from their own pups. For adult bats, females were attracted to the scent from both male and female groupmates but had a higher preference to the scent from female than from male groupmates. Male bats were much more attracted to the scent from male groupmates while showed no preference to the scent from female groupmates. Within a group, both female and male bats had no difference in preference to the scent from the same or opposite sex. These results suggest that mother–pup and groupmate recognition of T. pachypus can be achieved by olfactory cues.     

Managing Conflict between Bats and Humans: The Response of Soprano Pipistrelles (Pipistrellus pygmaeus) to Exclusion from Roosts in Houses

Conflict can arise when bats roost in human dwellings and householders are affected adversely by their presence. In the United Kingdom, the exclusion of bats from roosts can be licensed under exceptional circumstances to alleviate conflict, but the fate of excluded bats and the impact on their survival and reproduction is not well understood. Using radio-tracking, we investigated the effects of exclusion on the soprano pipistrelle Pipistrellus pygmaeus, a species that commonly roosts in buildings in Europe. Exclusions were performed under licence at five roosts in England in spring, when females were in the early stages of pregnancy. Following exclusion, all bats found alternative roosts and colonies congregated in nearby known roosts that had been used by radio-tagged bats prior to exclusion. We found no difference in roosting behaviour before and after exclusion. Both the frequency of roost switching and the type of roosts used by bats remained unchanged. We also found no change in foraging behaviour. Bats foraged in the same areas, travelled similar distances to reach foraging areas and showed similar patterns of habitat selection before and after exclusion. Population modelling suggested that any reduction in survival following exclusion could have a negative impact on population growth, whereas a reduction in productivity would have less effect. While the number of soprano pipistrelle exclusions currently licensed each year is likely to have little effect on local populations, the cumulative impacts of licensing the destruction of large numbers of roosts may be of concern.     

Sampling blood from big brown bats (Eptesicus fuscus) in the field with and without anesthesia: impacts on survival

Blood was collected from wild big brown bats (Eptesicus fuscus) with and without anesthesia in Fort Collins, Colorado in 2004 to assess the impacts of these procedures on short-term survival and 1-yr return rates. Short-term survival and 1-yr return rates after release were passively monitored using PIT tag detection hoops placed at selected buildings. Comparison of 14-day maximum likelihood survival estimates from bats not bled (142 adult females, 62 volant juveniles), and bats sampled for blood with anesthesia (96 adult females, 23 volant juveniles) and without anesthesia (112 adult females, 22 volant juveniles) indicated no adverse effects of either treatment (juveniles: chi(2) = 53.38, df = 41, P = 0.09; adults: chi(2) = 39.09, df = 44, P = 0.68). Return rates of bats one year after sampling were similar among adult female controls (75.4%, n = 142, 95% CI = 67.4-82.2%), females sampled for blood with anesthesia (83.0%, n = 112, 95% CI = 74.8-89.5%), and females sampled without anesthesia (87.5%, n = 96, 95% CI = 79.2-93.4%). Lack of an effect was also noted in 1-yr return rates of juvenile females. These data suggest that the use of anesthesia during sampling of blood has no advantages in terms of enhancement of survival in big brown bats.     

Ontogeny of 'true' flight and other aspects of growth in the bat Pipistrellus pipistrellus

We describe the ontogeny of pipistrelle bats Pipistrellus pipistrellus Schreber (Chiroptera: Vespertilionidae), including for the first time the development of true napping flight. The study animals were born to a group of 20 adults taken into captivity just before parturition, and allowed free flight and association within a room designed to approximate external conditions. All juveniles were aged to within one day and individually marked. All adults were ringed. Comparison to wild studies and the application of a set of growth models to forearm and body mass data gave no indication that development had been altered by captivity. Forearm data were best fitted by the logistic growth model and mass data by the 'Gompertz' growth model. Preliminary flight observations were followed, once the bats had become truly volant, by experiments in a flight enclosure with stroboscopic stereophotogrammetry. As the bats aged they used slower wingbeat frequencies (scaling with age D as D -^0–40), but flew faster, speed scaling with age as D ^0–65. Wingbeat amplitude did not alter significantly with age, nor did the total mechanical power for flight, calculated by using a flight performance model, although the cost of transport fell as the bats grew older. This was probably due to the improving efficiency of the wing; the development of wingspan, wing area, wing loading, aspect ratio and tip area ratio are presented, and adaptations for reducing the energy requirements during early flights are discussed. These included a mass recession which occurred after the time of first flights. The flight model was also used to explore the hypothetical flight of bats with the morphology of neonates, and we discuss the extent of sexual dimorphism in the young bats and in their mothers.     

Anesthesia and blood sampling of wild big brown bats (eptesicus fuscus) with an assessment of impacts on survival

We anesthetized and blood sampled wild big brown bats (Eptesicus fuscus) in Fort Collins, Colorado (USA) in 2001 and 2002 and assessed effects on survival. Inhalant anesthesia was delivered into a specially designed restraint and inhalation capsule that minimized handling and bite exposures. Bats were immobilized an average of 9.1+/-5.1 (SD) min (range 1-71, n=876); blood sample volumes averaged 58+/-12 microl (range 13-126, n=718). We randomly selected control (subject to multiple procedures before release) and treatment (control procedures plus inhalant anesthesia and 1% of body weight blood sampling) groups in 2002 to assess treatment effects on daily survival over a 14-day period for adult female and volant juvenile bats captured at maternity roosts in buildings. We monitored survival after release using passive integrated transponder tag detection hoops placed at openings to selected roosts. Annual return rates of bats sampled in 2001 were used to assess long-term outcomes. Comparison of 14-day maximum-likelihood daily survival estimates from control (86 adult females, 92 volant juveniles) and treated bats (187 adult females, 87 volant juveniles) indicated no adverse effect from anesthesia and blood sampling (juveniles: chi2=22.22, df=27, P>0.05; adults: chi2=9.72, df=18, P>0.05). One-year return rates were similar among adult female controls (81%, n=72, 95% confidence interval [CI]=70-91%), females treated once (82%, n=276, 95% CI=81-84%), and females treated twice (84%, n=50, 95% CI=74-94%). Lack of an effect was also noted in 1-yr return rates of juvenile female controls (55%, n=29, 95% CI=37-73%), juveniles treated once (66%, n=113, 95% CI=58-75%), and juveniles treated twice (71%, n=17, 95% CI=49-92%). These data suggest that anesthesia and blood sampling for health monitoring did not measurably affect survival of adult female and volant juvenile big brown bats.     

Suckling behaviour in the brown long-eared bat (Plecotus auritus)

Thirty-two adult female brown long-eard bats were taken into captivity. Eight individuals gave birth to single young in captivity (known mother-young pairs), 10 were lactating when captured (putative mother-young pairs), and the remaining 14 bats were non-reproductive. Bats were maintained in five groups consisting of females from sigle(n=3) or mixed (n=2) wild roosts. All bats were housed in outdoor, free-flight enclosures and fed mainly on free-flying noctuid moths. Bats were individually were determined daily (n=152) for a single gruup of bats containing four known mother-young pairs and five non-reproductive bats. The probability of a being attached to the nipple declined from 100% of records at 1-5 days of age to 5% of records at 36-40 days of age. Females were always found suckling their own young. Suckling associations were determined using infra-red sensitive video-recordings of bat behaviour within the roost box. For both known (n=8) and putative mother-young pairs (n=10), there were no records of young attached to lactating females other than their own mothers (from the same or different wild roosts).     

Host sex and ectoparasites choice: preference for, and higher survival on female hosts

1. Sex differences in levels of parasite infection are a common rule in a wide range of mammals, with males usually more susceptible than females. Sex-specific exposure to parasites, e.g. mediated through distinct modes of social aggregation between and within genders, as well as negative relationships between androgen levels and immune defences are thought to play a major role in this pattern. 2. Reproductive female bats live in close association within clusters at maternity roosts, whereas nonbreeding females and males generally occupy solitary roosts. Bats represent therefore an ideal model to study the consequences of sex-specific social and spatial aggregation on parasites' infection strategies. 3. We first compared prevalence and parasite intensities in a host-parasite system comprising closely related species of ectoparasitic mites (Spinturnix spp.) and their hosts, five European bat species. We then compared the level of parasitism between juvenile males and females in mixed colonies of greater and lesser mouse-eared bats Myotis myotis and M. blythii. Prevalence was higher in adult females than in adult males stemming from colonial aggregations in all five studied species. Parasite intensity was significantly higher in females in three of the five species studied. No difference in prevalence and mite numbers was found between male and female juveniles in colonial roosts. 4. To assess whether observed sex-biased parasitism results from differences in host exposure only, or, alternatively, from an active, selected choice made by the parasite, we performed lab experiments on short-term preferences and long-term survival of parasites on male and female Myotis daubentoni. When confronted with adult males and females, parasites preferentially selected female hosts, whereas no choice differences were observed between adult females and subadult males. Finally, we found significantly higher parasite survival on adult females compared with adult males. 5. Our study shows that social and spatial aggregation favours sex-biased parasitism that could be a mere consequence of an active and adaptive parasite choice for the more profitable host.     

Territorial Advertisement and Mate Attraction in the Bat Pipistrellus pipistrellus

A South Swedish population of the vespertilionid bat Pipistrellus pipistrellus was studied by means of bat boxes from April to the beginning of October in 1984. The mating system of the pipistrelle bat is a “resource defence polygyny”. Three territorial males were studied to determine the relative importance of two potential resources, food and roost sites, for male reproductive success. The day roost was found to be the crucial resource for the male's chances to get access to females. A territorial male advertises the location of his day roost to the females by a songflight display. The male who spent most time in songflight display was visited by the greatest number of females.     

Variability in Seroprevalence of Rabies Virus Neutralizing Antibodies and Associated Factors in a Colorado Population of Big Brown Bats (Eptesicus fuscus)

In 2001–2005 we sampled permanently marked big brown bats (Eptesicus fuscus) at summer roosts in buildings at Fort Collins, Colorado, for rabies virus neutralizing antibodies (RVNA). Seroprevalence was higher in adult females (17.9%, n = 2,332) than males (9.4%, n = 128; P = 0.007) or volant juveniles (10.2%, n = 738; P<0.0001). Seroprevalence was lowest in a drought year with local insecticide use and highest in the year with normal conditions, suggesting that environmental stress may suppress RVNA production in big brown bats. Seroprevalence also increased with age of bat, and varied from 6.2 to 26.7% among adult females at five roosts sampled each year for five years. Seroprevalence of adult females at 17 other roosts sampled for 1 to 4 years ranged from 0.0 to 47.1%. Using logistic regression, the only ranking model in our candidate set of explanatory variables for serological status at first sampling included year, day of season, and a year by day of season interaction that varied with relative drought conditions. The presence or absence of antibodies in individual bats showed temporal variability. Year alone provided the best model to explain the likelihood of adult female bats showing a transition to seronegative from a previously seropositive state. Day of the season was the only competitive model to explain the likelihood of a transition from seronegative to seropositive, which increased as the season progressed. We found no rabies viral RNA in oropharyngeal secretions of 261 seropositive bats or in organs of 13 euthanized seropositive bats. Survival of seropositive and seronegative bats did not differ. The presence of RVNA in serum of bats should not be interpreted as evidence for ongoing rabies infection.     

Helminth parasites in ringed seals (Pusa hispida) from Svalbard, Norway with special emphasis on nematodes: variation with age, sex, diet, and location of host

Complete gastrointestinal tracts from 257 ringed seals (Pusa hispida) from Svalbard, Norway, were examined for helminth parasites. Three different helminth groups were recorded (acanthocephalans 61.1%; nematodes 38%; cestodes 0.9%). Acanthocephalans (Polymorphidae) and cestodes (Anophryocephalus and Diphyllobothrium sp(p)., as well as unidentified species, were confined to the intestines. The anisakid nematodes Phocascaris phocae, Pseudoterranova sp(p)., Anisakis sp(p)., and Phocascaris/Contracaecum sp(p). were recorded in both stomachs and the anterior part of the small intestines. The abundance of nematodes and acanthocephalans varied significantly with sampling location of the seal hosts. This is likely due to the relative prevalence of Arctic versus Atlantic water in the different fjord systems, which strongly influences the age class and species of fish available as prey for the seals. Adult male ringed seals had significantly higher abundances of nematodes than did adult females or juveniles. Adult males also had significantly higher abundances of acanthocephalans than did adult females, but were not significantly different from juveniles in this regard. Nematode abundance increased significantly with age of male hosts, but this trend was lacking in female seals. Infection parameters appeared to be related to differences in the age of polar cod (Boreogadus saida) exploited by male, female, and juvenile seals.     

A population study of bats of the Genus Plecotus

In November 1960, bat colonies were found in the roof of the research station, and an ecological study began of the largest, a Plecotus colony. That colony was at first thought to consist solely of P. auritus but, in 1964, the presence of P. austriacus was confirmed, and several of the latter had been ringed early in 1961. Because of this, it has been necessary to present, here, the combined results for the two species. Population studies revealed that the colony size was constant and consisted of 36 bats of which 23 were females. Overall 38% were males but, of the juveniles, 46% were males. The survival rate for the colony as a whole was 0.750, but the mean life expectation for females was 4.2 years and for males 3.7 years. The life-span was thought to be in excess of 16 years. Initial capture rate of 0.715 remained constant throughout the five-year period, while the recapture rate fell by a factor of 0.30. This was attributed to sampling disturbance and not due to ringing. Mating was found to occur equally in spring and autumn. Males became mature in their first year and females in their second. The mean spring and autumn weights for mature males were generally 1.5g less than the corresponding mature female weights, and juvenilesare approximately 1.0 g less than these. Climatic effects on the bats were demonstrated with particular reference to wind velocity. This work is beingcontinued.     

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。     

Variation in intensity of a parasitic mite (Spinturnix myoti) in relation to the reproductive cycle and immunocompetence of its bat host (Myotis myotis)

Given the intimate association in host–parasite systems, parasites are expected to initiate their own reproduction when vulnerable hosts become abundant and/or when adult hosts are less resistant. In this study, we examined the variation in the intensities of a blood-sucking mite ( Spinturnix myoti , Acarina) with respect to the reproductive cycle and immunocompetence of its host, the greater mouse-eared bat Myotis myotis . Reproductive, pregnant females were less immunocompetent and harboured more parasites than nonreproductive females, whilst, during lactation, immunocompetence was positively associated with female body mass. There was a dramatic increase in the T-cell response of gravid females with the advancement of gestation, which coincided with a diminution of individual parasite loads and a progressive switch of parasites from adults to juveniles. The latter not only harboured greater numbers of mites than adult female bats, but they also exhibited gravid parasites in higher proportions, indicating that juvenile hosts are more attractive for parasite reproduction than adult females.     

Discriminate suckling in pipistrelle bats is supported by DNA fingerprinting

DNA fingerprints were obtained by using Jeffreys' probes 33.6 and 33.15 with DNA extracted from nine mother-young pairs of pipistrelle bats Pipistrellus pipistrellns to investigate the feasibility of this technique for determining relatedness in this species. The bats had mated in the wild and gave birth in captivity. All of nine pairs in which infants were found attached showed band-sharing coefficients higher than those for individuals presumed to be unrelated but run in adjacent lanes of the gels. We therefore conclude that all attached infants were probably true offspring.     

Infestation and seasonal activity of Ixodes vespertilionis Koch, 1844 (Acari: Ixodidae) on the Maghreb mouse‐eared bat,Myotis punicus Felten, 1977, in northeastern Algeria

Infestation of Ixodes vespertilionis Koch, 1844 on Myotis punicus Felten, 1977 from two sites (Trios Tunnel and Sidi Trad cave) in northeastern Algeria was studied. An overall infestation of 41.4% for all stages was found among bats collected from both sites. By stage, a total of eight females, 70 nymphs, and 107 larvae were recovered from both populations. The number of females recovered per bat at Sidi Trad ranged from 0‐1, for nymphs 0‐2, and for larvae 0‐2. While no female ticks were collected at Trios Tunnel, the number of nymphs ranged from 0‐2 and for larvae 0‐2. At Trios Tunnel, the number of nymphs was significantly higher during April and June but not for July and September. On the other hand, the number of larvae increased from July to November, while at Sidi Trad cave, female ticks were recovered during April and May and then disappeared until the end of the study period. Significant differences were noted during all the months when compared with all stages. Nymphs infested bats significantly during April and May, declined in June and July, and then became steady until October. Larvae peaked in July, with low frequency in April, and then fluctuated from August to November.