Trichobius joblingi, Aspidoptera falcata, and Megistopoda proxima (Diptera : Streblidae) parasitic on Carollia perspicallata and Sturnia lillium (Chiroptera : Phyllostomidae) in southeastern Brazil: sex ratios, seasonality, host site preference, and effect of parasitism on the host

This note examines the effect of parasitism on host size, the preference of the parasite for a specific host body area, and the seasonal abundance for the 3 most abundant bat flies (i.e., Trichobius joblingi Wenzel, a parasite of the bat Carollia perspicillata [Linnaeus], and Aspidoptera falcata Wenzel and Megistopoda proxima [Séguy], parasites on Sturnira lilium [Geoffroy]). Trichobius joblingi and A. falcata are moderately dorsoventrally flattened and were collected on the wing membranes of their hosts, and M. proxima is moderately laterally compressed, has long, thin hind legs, and was collected in the body fur of the host. These 3 parasites also showed distinct seasonal patterns. There was a significant negative correlation between the simultaneous occurrence of A. falcata and M. proxima on the host. Parasitism by M. proxima was correlated with a significant weight loss in male S. lilium, which may reflect the large size, high activity, and constant feeding of this parasite, thereby causing a significant negative effect on the host. Sex ratios favoring male flies could be explained by the tendency of female flies to leave the host immediately before the bat leaves the shelter in search for food or immediately after bats are collected but could also be a consequence of higher mortality among females, especially gravid ones. Finally, collecting may have influenced the skewed sex ratio because male flies, being more active, were more evident to the collector.     

Bat flies on phyllostomid hosts in the Cerrado region: component community, prevalence and intensity of parasitism

Streblidae flies are specialised parasites of bat hosts, mainly phyllostomids. There is a high richness of streblids in the savannah-like Cerrado region; however, there is little quantitative data available in parasitological indices. Here, we describe the component community, prevalence and intensity of a streblid infestation on a phyllostomid bat assemblage in Serra da Bodoquena, a Cerrado region in Southwest Brazil. We conducted surveys by capturing and inspecting bat hosts during the seven-month period between October 2004-December 2005. All the ectoparasites found on the bats were collected in the field and then counted and identified in the laboratory. We captured 327 bats belonging to 13 species, of which eight species were parasitized by 17 species of streblids. Carollia perspicillata and Glossophaga soricina were infested with seven streblid species, whereas the other bat species were infested with four or fewer streblid species. Megistopoda proxima and Aspidoptera falcata flies were found on Sturnira lilium, and Trichobius joblingi was the most prevalent fly on C. perspicillata. Megistopoda aranea and Aspidoptera phyllostomatis were highly prevalent and had a high intensity of infestation on Artibeus planirostris. Overall comparisons of the available data suggest that the component communities of streblids vary more between the Cerrado and Atlantic Forest phytogeographical regions than between localities within the same phytogeographical region.     

Bat flies (Diptera: Streblidae, Nycteribiidae) parasitic on bats (Mammalia: Chiroptera) at Parque Estadual da Cantareira, São Paulo, Brazil: parasitism rates and host-parasite associations

A total of 443 bat flies belonging to the families Nycteribiidae and Strelidae, were collected on 22 species of bats (Molossidae, Phyllostomidae, and Vespertilionidae) from Parque Estadual da Cantareira (S?o Paulo, Brazil), between January, 2000 and January, 2001. Eighteen new occurrences of bat flies were recorded on Anoura geoffroyi (Anastrebla caudiferae), Glossophaga soricina (A. caudiferae), Sturnira lilium (Trichobius phyllostomae, T. furmani, and Paraeuctenodes similis), Artibeus lituratus (A. caudiferae), A. fimbriatus (Megistopoda proxima), A. obscurus (Metelasmus pseudopterus), Myotis nigricans (M. proxima, M. aranea, Paratrichobius longicrus), M. ruber (Anatrichobius passosi, Joblingia sp.), M. levis (A. passosi), M. albescens (A. passosi, Basilia andersoni), and Histiotus velatus (M. aranea). Seven new occurrences were recorded for the state of S?o Paulo, increasing the range for T. tiptoni, T. furmani, M. proxima, Aspidoptera falcata, A. caudiferae, A. modestini and B. andersoni. The relationships between parasitism and host sex, reproductive stage, age hyperparasitism by fungi are discussed.     

Does the mode of transmission between hosts affect the host choice strategies of parasites? Implications from a field study on bat fly and wing mite infestation of Bechstein's bats

In a two-year field study, we analyzed the distribution of two hematophagous ectoparasites, the bat fly Basilia nana and the wing mite Spinturnix bechsteini , within and among 14 female colonies and among 26 solitary male Bechstein's bats Myotis bechsteinii . Our goal was to investigate whether differences in the transmission mode of the parasites, which result from differences in their life cycle, affect their distribution between host colonies and among host individuals within colonies. Bat flies deposit puparia in bat roosts, allowing for the transmission of hatched flies via successively shared roosts, independent of body contact between hosts or of hosts occupying a roost at the same time. In contrast, wing mites stay on the bat's body and are transmitted exclusively by contact of bats that roost together. As expected in cases of higher inter-colony transmissibility, bat flies were more prevalent among the demographically isolated Bechstein's bat colonies and among solitary male bats, as compared to wing mites. Moreover, the prevalence and density of wing mites, but not of bat flies, was positively correlated with colony size, as expected in cases of low inter-colony transmissibility. Within colonies, bat flies showed higher abundance on host individuals in good body condition, which are likely to have high nutritional status and strong immunity. Wing mites showed higher abundance on hosts in medium body condition and on reproductive females and juveniles, which are likely to have relatively weak immunity. We suggest that the observed infestation patterns within host colonies reflect different host choice strategies of bat flies and wing mites, which may result from differences in their inter-colony transmissibility. Our data also indicate that infestation with wing mites, but not with bat flies, might be a cost of sociality in Bechstein's bats.     

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.     

An excess of males: skewed sex ratios in bat flies (Diptera: Streblidae)

Ectoparasitic insects often exhibit female-biased sex ratios, a pattern usually explained by greater female longevity and the likelihood that smaller, more active males will disperse or be groomed off the host. Theory predicts that unbalanced sex ratios should favor males when resources are abundant and predictable, and when males are the dispersing sex. Sex ratios of streblid bat flies were evaluated based on a large biodiversity survey in Venezuela–more than 25,000 bats representing 130 species were searched for flies, yielding more than 36,500 bat flies of 116 species. These samples allowed us to analyze sex ratios in 112 bat fly metapopulations. Our results indicate that fully one-third of these metapopulations were significantly male-biased. Traditional explanations for sex-ratio bias, such as sampling effects, unequal longevity between the sexes, and differential dispersal capability are refuted for bat flies in favor of an alternative hypothesis—selective host grooming. Because host grooming is the principal cause of mortality for these slow-reproducing parasites, and because females are larger than males and gravid for a significant portion of their adult life, host grooming activity is more likely to kill or remove females than males. Incomplete understanding of population dynamics, such as mating behavior, dispersal, and reproductive success, cloud applications of male-biased sex ratios in bat flies to support or refute theoretical predictions. Population studies of mating competition and sex-related dispersal dynamics of this male-dominated group should yield important insights into sex ratio theory.     

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.     

Against all odds: explaining high host specificity in dispersal-prone parasites

Host specificity gauges the degree to which a parasite occurs in association with a single host species. The measure is indicative of properties of the host and parasite, as well as their ecological and co-evolutionary relationships. Host specificity is influenced by the behavior and ecology of both parasite and host. Where parasites are active, vagile and coupled with hosts whose behavior and ecology brings the parasite into contact with many potential hosts, the likelihood of host switching is increased, usually leading to lowered specificity. Bat flies are specialized, blood-feeding ectoparasites of bats worldwide. In the bat fly - bat system, numerous properties interrupt the linkage of parasite to host and should decrease specificity. For bat flies these include high levels of activity, proclivity to abandon a disturbed host, the ability to fly, and a life-history strategy that includes a pupal stage decoupled from the host. For bats these include rapid, frequent and wide-ranging flight, high species richness encouraging inter-specific encounters during foraging, roosting and reproductive events, the utilization of large, durable roosting structures that are often shared with other bat species, and utilization of common entrance/exit flyways. The biological and ecological characteristics of bats and flies should together facilitate interspecific host transfers and, over time, lead to non-specific host-parasite associations. Large surveys of Neotropical mammals and parasites, designed to eliminate artifactual host-to-host parasite transfers, unequivocally demonstrate the high host specificity of bat flies. High degrees of specificity are remarkable in light of myriad host and parasite characteristics that ought to break down such specificity. Although host-specific parasites often have limited dispersal capability, this is not the case for some groups, including active, mobile bat flies. Host specificity in parasites with high dispersal capability is likely related to adaptive constraints. Among these may be a reproductive filter selecting for specificity based on mate availability, and co-evolved immunocompatibility where parasites use the same or similar immune-signaling molecules as their hosts to avoid immunological surveillance and response.     

Curiosity killed the bat: Domestic cats as bat predators

Domestic cats are suspected to have an impact on wild populations of birds and small mammals, but published reports of predation on bats are either rare or anecdotal. We based our study on 1012 records of bats admitted at four wildlife rescue centres in peninsular Italy in 2009–2011. We hypothesized that (1) cats prevalently prey on bats emerging from roosts, so newborns or non volant juveniles should be less exposed to predation; (2) because cats occur in human settlements, the bat species most frequently involved are house-roosting (3) predation is season-biased, most events being more likely to take place in summer when females congregate in roosts to reproduce; (4) predation events concentrate in sparse-urban and rural areas, where free-ranging cats occur more frequently; and (5) some individual cats may specialize in capturing bats. We found that predation by cats was the first cause of rescue for bats in the study area, accounting for 28.7% of records of adult bats admitted to rehabilitation centres. Although most bats caught by cats belonged to house-roosting species, at least 3 of the 11 species affected were tree- or cave-roosting. Predation affected more frequently adult females in summer and thus threatened reproductive colonies, which were often subjected to repeated predations. As predicted, predation events were associated with land cover, being more abundant in rural and sparse urban areas, where cats are more often allowed to stay outdoor, as confirmed by the results of a cat owner survey we carried out. Cats are explorative mammals, so they may be easily attracted at bat roosts by sensory cues involving sound, smell and vision. Our analysis covered a broad geographical area over a relatively long period and suggests that the threat posed to bats by cats may be significant and should be carefully considered in conservation plans. Strategies to mitigate this impact should encompass the control of feral cat populations and indoor restriction of owned cats at least where predation on bats is probable.     

Parasitization of bats by bat flies (Streblidae) in fragmented habitats

Parasites represent a large fraction of the world's biodiversity. They control host population sizes and contribute to ecosystem functioning. However, surveys on species diversity rarely include parasitic species. Bats often present traits favoring parasite diversity, such as large home ranges, long life spans, and large colonies. The most conspicuous bat parasites are the highly host-specific, blood-sucking bat flies (Diptera: Streblidae, Nycteribiidae). Recent studies have found a direct effect of habitat alteration on the abundance of bat species. We expected, therefore, that changes in the host community in response to anthropogenic habitat modification will also result in changes in the associated parasite community. We captured bats in three different habitats in Central Panama between 2013 and 2015. We recorded information on prevalence and intensity of bat fly parasitization of the seven most commonly captured bat species. Prevalence and intensity were both significantly influenced by roost type, abundance, and host sex and age. We found that habitat variables and matrix type significantly influenced the prevalence and intensity of parasitization, while the direction of the responses was host species- and parasite species-specific. In general, roosting conditions and behavior of host bats appear to be fundamental in explaining changes in prevalence and intensity of parasitization between different habitat types, as bat flies are bound to the roost during their reproductive cycle. Habitat alterations affect next to the host community composition also the availability of possible roost structures as well as microclimatic conditions, which all three reflect in parasitization.     

Ambient temperature correlates with geographic variation in body size of least horseshoe bats

Geographic variation in body size is common within many animal species. The causes of this pattern, however, remain largely unexplored in most vertebrate groups. Bats are widely distributed globally owing to their ability of powered flight. Most bat species encounter a variety of climatic conditions across their distribution range, making them an ideal taxon for the study of ecogeographic patterns in body size. Here, we used adult least horseshoe bats, Rhinolophus pusillus, to test whether geographic variation in body size was determined by heat conservation, heat dissipation, climatic seasonality, or primary productivity. We measured body mass and head-body length for 246 adult bats from 12 allopatric colonies in China. We quantified the ecological conditions inhabited by each colony, including mean maximum temperature of the warmest month, mean minimum temperature of the coldest month, temperature seasonality, precipitation seasonality, and annual net primary productivity (ANPP). Body mass and head-body length, 2 of the most reliable indicators of body size, exhibited marked differences between colonies. After controlling for spatial autocorrelation, the mean minimum temperature of the coldest month explained most of the variation in body size among colonies, regardless of sex. The mean maximum temperature, climatic seasonality, and ANPP had limited power in predicting body size of males or females in comparison with mean minimum temperature. These results support the heat conservation hypothesis and suggest adaptive responses of body size to cold climates in cave-dwelling bats.     

Fitness consequences of ecological constraints and implications for the evolution of sociality in an incipiently social bee

Ecological constraints such as resource limitation, unfavourable weather conditions, and parasite pressure have long been considered some of the most important selective pressures for the evolution of sociality. In the present study, we assess the fitness consequences of these three ecological factors on reproductive success of solitary nests and social colonies in the socially polymorphic small carpenter bee, Ceratina australensis, based on 982 nests collected over four reproductive periods. Nest site limitation was predicted to decrease opportunities for independent nest initiation and increase the frequency of social nesting. Nest sites were not limiting in this species and the frequency of social nesting was consistent across the four brood‐rearing periods studied. Unfavourable weather was predicted to lower the frequency of female dispersal from their natal nests and to limit the brood‐rearing season; this would increase the frequency and fitness of social colonies. Daily temperature and precipitation accumulation varied between seasons but were not correlated with reproductive success in this bee. Increased parasite pressure is predicted to increase the frequency and fitness of social colonies because solitary bees must leave the nest unattended during foraging bouts and are less able to defend the nest against parasites. Severe parasitism by a chalcid wasp (Eurytoma sp.) resulted in low reproductive success and total nest failure in solitary nests. Social colonies had higher reproductive success and were never extirpated by parasites. The high frequency of solitary nests suggests that this is the optimal strategy. However, social colonies have a selective advantage over solitary nesting females during periods of extreme parasite pressure, and we suggest that social nesting represents a form of bet‐hedging against unpredictable fluctuations in parasite number. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 57–67.     

Longevity and survival of female pipistrelle bats (Pipistrellus pipistrellus) on the Vale of York, England

Female pipistrelle bats ( Pipistrellus pipistrellus Schreber) form large nursery colonies in summer. Between 1977 and 1984, around York in the north of England, 1328 pipistrelle bats were ringed. Ninety adult females were ringed in 1977, and from capture, release and recapture data life tables for an unaged female cohort were constructed. Age-specific survival rate for adult females on the Vale of York was 0–64 per year. Three bats from the original 1977 cohort were recaptured in 1984 and are likely to have been at least eight years old. Juvenile female pipistrelles appear to survive less well than adults.     

Advantages of multiple foundress colonies in Belonogaster juncea juncea L.: greater survival and increased productivity

Abstract.  1. The ecological hypothesis predicts that multiple foundress colonies of social wasps may have a better survival rate and produce more brood per capita than single foundress colonies. With the aim of verifying if these characteristics exist in the primitively eusocial wasp species Belonogaster juncea juncea (L.), we monitored 49 foundations, including 13 single and 36 multiple foundress colonies, in Cameroon.
2. Multiple foundress colonies were significantly more successful than single foundress colonies in producing at least one adult.
3. The total productivity of the colonies increased significantly with the number of associated foundresses, but the productivity per capita did not. No single foundress colony reached the sexual phase, while eight (21.6%) multiple foundress colonies did. Males were produced in only five colonies, so that the sex ratio was biased in favour of females.
4. These results suggest that because of the strong ecological constraints on solitary nesting, survival and high colony productivity are two advantages of multiple foundress colonies in B. j. juncea .
5. The decreasing per capita productivity concomitant with an increasing number of females noted in this study illustrates once again Michener's paradox. The coefficient of variance of the per capita productivity significantly decreased with group size, as Wenzel and Pickering suggested in the model they created to explain the paradox.
6. Ecological factors may act in conjunction with other factors, such as genetic relatedness between associated foundresses, to promote joining behaviour in B. j. juncea .     

Spatial and temporal complexities of reproductive behavior and sex ratios: a case from parasitic insects

Background

Sex ratios are important empirical data in predicting sex allocation strategy and selection in populations. Therefore, they should be sampled at crucial developmental steps before and after parental investment. In parasites with free-living (off-host) developmental stages the timing and method of sampling is not trivial, because ecological niches are frequently poorly known. Consequently, information is scarce for sex ratios of these parasites between conception and sexual maturity. Often, only data from adult parasites are available, which usually were collected from the parasite''s hosts. Generally, these ratios are assumed to represent operational sex ratios.

Methodology/Principal Findings

We here report three years of empirical data on population sex differentials from a bat ectoparasite (Trichobius frequens) with off-host developmental stages. At emergence these parasites exhibit a significant and seasonally stable female biased sex ratio. This bias is lost in the adult population on the roosting host, which shows sex ratios at equality. This is best explained by a behaviorally driven, sex-dependent mortality differential. Because consistently only subsets of females are available to mate, the operational sex ratio in the population is likely male biased. Host capture experiments throughout the day show a statistically significant, but temporary male excess in bat flies on foraging bats. This phenomenon is partly driven by the diurnal rhythms of female larviposition, and partly due to parasites remaining in the bat roost during foraging. Because most previous research in bat flies is based only on foraging bats, female contributions to physical sex ratios have been underestimated.

Conclusion/Significance

Our results highlight the importance of detailed natural history observations, and emphasize that ignoring the spatial and temporal heterogeneity of reproduction in any organism will lead to significant empirical sampling errors of sex ratios, and may obscure operational sex ratios.     

Streblidae (Diptera) of phyllostomid bats from Minas Gerais,Brazil

Eight streblid species were collected from eight phyllostomid bat species, from April to November 1997, at or near the Reserve "Parque Estadual do Rio Doce", Minas Gerais, Southeastern Brazil. In total, 48 specimens of streblid were removed from 57 phyllostomid bats. Most of batflies species were associated with a single species of the host, and only Paratrichobius longicrus (Miranda Ribeiro) and Trichobius joblingi Wenzel were recorded on three bat species. Trichobius lonchophyllae Wenzel represents a new record for the Brazilian Southeastern region.     

Sexually selected infanticide in a polygynous bat

Background

Adult individuals of many species kill unrelated conspecific infants for several adaptive reasons ranging from predation or resource competition to the prevention of misdirected parental care. Moreover, infanticide can increase the reproductive success of the aggressor by killing the offspring of competitors and thereafter mating with the victimized females. This sexually selected infanticide predominantly occurs in polygynous species, with convincing evidence for primates, carnivores, equids, and rodents. Evidence for bats was predicted but lacking.

Methodology/Principal Findings

Here we report the first case, to our knowledge, of sexually selected infanticide in a bat, the polygynous white-throated round-eared bat, Lophostoma silvicolum. Behavioral studies in a free-living population revealed that an adult male repeatedly attacked and injured the pups of two females belonging to his harem, ultimately causing the death of one pup. The infanticidal male subsequently mated with the mother of the victimized pup and this copulation occurred earlier than any other in his harem.

Conclusions/Significance

Our findings indicate that sexually selected infanticide is more widespread than previously thought, adding bats as a new taxon performing this strategy. Future work on other bats, especially polygynous species in the tropics, has great potential to investigate the selective pressures influencing the evolution of sexually selected infanticide and to study how infanticide impacts reproductive strategies and social structures of different species.     

Climate change and the effects of temperature extremes on Australian flying-foxes

Little is known about the effects of temperature extremes on natural systems. This is of increasing concern now that climate models predict dramatic increases in the intensity, duration and frequency of such extremes. Here we examine the effects of temperature extremes on behaviour and demography of vulnerable wild flying-foxes (Pteropus spp.). On 12 January 2002 in New South Wales, Australia, temperatures exceeding 42 degrees C killed over 3500 individuals in nine mixed-species colonies. In one colony, we recorded a predictable sequence of thermoregulatory behaviours (wing-fanning, shade-seeking, panting and saliva-spreading, respectively) and witnessed how 5-6% of bats died from hyperthermia. Mortality was greater among the tropical black flying-fox, Pteropus alecto (10-13%) than the temperate grey-headed flying-fox, Pteropus poliocephalus (less than 1%), and young and adult females were more affected than adult males (young, 23-49%; females, 10-15%; males, less than 3%). Since 1994, over 30000 flying-foxes (including at least 24500 P. poliocephalus) were killed during 19 similar events. Although P. alecto was relatively less affected, it is currently expanding its range into the more variable temperature envelope of P. poliocephalus, which increases the likelihood of die-offs occurring in this species. Temperature extremes are important additional threats to Australian flying-foxes and the ecosystem services they provide, and we recommend close monitoring of colonies where temperatures exceeding 42.0 degrees C are predicted. The effects of temperature extremes on flying-foxes highlight the complex implications of climate change for behaviour, demography and species survival.     

Description of the external morphology of the puparia of eight species of bat flies (Diptera: Streblidae)

ABSTRACT

The Dipteran family Streblidae are ectoparasites of bats. These flies are viviparous and have an intrauterine larval life phase, a free-living sessile puparium phase and the adult obligate parasite. Here we describe the external morphology of the puparium of Aspidoptera phyllostomatis (Perty, 1833), Megistopoda aranea (Coquillett, 1899), M. proxima (Séguy, 1826), Noctiliostrebla morena Alcantara et al., 2019, Paradyschiria parvula Falcoz, 1931, Strebla consocia Wenzel, 1966, Trichobius joblingi Wenzel, 1966 and T. longipes (Rudow, 1871) and provide an identification key. We also describe the method we developed for collecting the puparia, which was done between April 2015 and August 2016. The characters that most differentiated the species were spiracles and ornaments.     

Parentage, reproductive success and breeding behaviour in the greater horseshoe bat (Rhinolophus ferrumequinum)

Female greater horseshoe bats form maternity colonies each summer in order to give birth and raise young. During the mating period, females visit males occupying territorial sites, copulation takes place and sperm are stored until ovulation occurs, normally in April. Using microsatellite markers and a likelihood method of parentage analysis, we studied breeding behaviour and male reproductive success over a five-year period in a population of bats in south-west Britain. Paternity was assigned with 80% confidence to 44% of young born in five successive cohorts. While a small annual skew in male reproductive success was detected, the variance increased over five years due to the repeated success of a few individuals. Mating was polygynous, although some females gave birth to offspring sired by the same male in separate years. Such repeated partnerships probably result from fidelity for either mating sites or individuals or from sperm competition. Females mated with males born both within and outside their own natal colony; however, relatedness between parents was no less than the average recorded for male female pairs. Gene flow between colonies is likely to be primarily mediated by both female and male dispersal during the mating period rather than more permanent movements.