The reproductive success of the parasitic bat fly Basilia nana (Diptera: Nycteribiidae) is affected by the low roost fidelity of its host, the Bechstein's bat ( Myotis bechsteinii )

We studied the reproductive ecology of the bat fly Basilia nana on free-ranging colonial female and solitary male Bechstein's bats (Myotis bechsteinii) during one reproductive season. The reproduction of B. nana took place from April to September, and the production of puparia in bat roosts was high. The metamorphosis of the flies took a minimum of 30days, and at least 86% of the puparia metamorphosed successfully. However, only about 30% of flies from puparia deposited in female roosts and 57% of flies from puparia deposited in male roosts emerged in the presence of Bechstein's bats and were thus able to survive. The significantly higher emergence success of bat flies in male roosts was caused by the higher roost fidelity of the solitary males compared with the social females. Our results indicate that bats can control the reproductive success of bat flies by switching and selecting roost

Roost selection and roost switching of female Bechstein's bats ( Myotis bechsteinii ) as a strategy of parasite avoidance

Ectoparasites of vertebrates often spend part of their life cycle in their hosts' home. Consequently, hosts should take into account the parasite infestation of a site when selecting where to live. In a field study, we investigated whether colonial female Bechstein's bats (Myotis bechsteinii) adapt their roosting behaviour to the life cycle of the bat fly Basilia nana in order to decrease their contact with infective stages of this parasite. B. nana imagoes live permanently on the bat's body but deposit puparia in the bat's roosts. The flies metamorphose independently in the roosts, but after metamorphosis emerge only in the presence of a potential host. In a field experiment, the bats preferred non-contagious to contagious day-roosts and hence were able to detect either the parasite load of roosts or some correlate with infestation, such as bat droppings. In addition, 9 years of observational data on the natural roosting behaviour of female Bechstein's bats indicate that the bats largely avoid re-occupying roosts when highly contagious puparia are likely to be present as a result of previous occupations of the roosts by the bat colony. Our results indicate that the females adapted their roosting behaviour to the age-dependent contagiousness (emergence probability) of the puparia. However, some infested roosts were re-occupied, which we assume was because these roosts provided advantages to the bats (e.g. a beneficial microclimate) that outweighed the negative effects associated with bat fly infestation. We suggest that roost selection in Bechstein's bats is the outcome of a trade-off between the costs of parasite infestation and beneficial roost qualitie

All-offspring dispersal in a tropical mammal with resource defense polygyny

In polygynous mammals, males are usually responsible for gene flow while females are predominantly philopatric. However, there is evidence that in a few mammalian species female offspring may disperse to avoid breeding with their father when male tenure exceeds female age at maturity. We investigated offspring dispersal and local population structure in the Neotropical bat Lophostoma silvicolum. The mating system of this species is resource defense polygyny, with the resource being active termite nests, excavated by single males, which are then joined by females. We combined field observations of 14 harems during 3years and data about the genetic structure within and between these groups, calculated with one mitochondrial locus and nine nuclear microsatellite loci. The results show that both male and female offspring disperse before maturity. In addition, we estimated life span of excavated termite nests and the duration they were occupied by the same male. Our findings suggest that long male tenure of up to 30months is indeed a likely cause for the observed dispersal by female offspring that can reach maturity at a low age of 6months. We suggest that dispersal by offspring of both sexes may occur quite frequently in polygynous tropical bats and thus generally may be more common in mammals than previously assume

Genetic sexing of stock-raiding leopards: not only males to blame

Lethal control of stock-raiding predators is generally assumed to have fewer consequences for the species' population dynamics if it involves males only. However, very little data are available that assess whether shot "problem” animals indeed are essentially males. In this study, we used two independent genetic methods (four X-chromosomal polymorphic microsatellite loci and the sex-specific ZFXY marker) validated against known-sex samples to determine, from skin samples collected over a 6-year period, the sex of 59 leopards (Panthera pardus) shot by farmers in Botswana. We found that out of 53 leopards that could be sexed genetically, 21 were females (39.6%); males were thus not significantly more often shot than females. Comparing the genetically determined sex of shot leopards to that reported by farmers showed that 58.3% were mistaken for the opposite sex. Our genetic study revealed that more females than presumed are hunted in response to alleged livestock predation. With females frequently misidentified as males, the current practice of shooting "problem” animals is likely to negatively affect the population dynamics of leopards. These genetic data may be used to guide the development of a revised management policy for large-carnivore hunting. Importantly, models of sustainable harvest need to include female off-take as a paramete

Genetic sexing of stock-raiding leopards: not only males to blame

Lethal control of stock-raiding predators is generally assumed to have fewer consequences for the species' population dynamics if it involves males only. However, very little data are available that assess whether shot "problem” animals indeed are essentially males. In this study, we used two independent genetic methods (four X-chromosomal polymorphic microsatellite loci and the sex-specific ZFXY marker) validated against known-sex samples to determine, from skin samples collected over a 6-year period, the sex of 59 leopards (Panthera pardus) shot by farmers in Botswana. We found that out of 53 leopards that could be sexed genetically, 21 were females (39.6%); males were thus not significantly more often shot than females. Comparing the genetically determined sex of shot leopards to that reported by farmers showed that 58.3% were mistaken for the opposite sex. Our genetic study revealed that more females than presumed are hunted in response to alleged livestock predation. With females frequently misidentified as males, the current practice of shooting "problem” animals is likely to negatively affect the population dynamics of leopards. These genetic data may be used to guide the development of a revised management policy for large-carnivore hunting. Importantly, models of sustainable harvest need to include female off-take as a paramete

Coprophagous features in carnivorous Nepenthes plants: A task for ureases

Most terrestrial carnivorous plants are specialized on insect prey digestion to obtain additional nutrients. Few species of the genus Nepenthes developed mutualistic relationships with mammals for nitrogen supplementation. Whether dietary changes require certain enzymatic composition to utilize new sources of nutrients has rarely been tested. Here, we investigated the role of urease for Nepenthes hemsleyana that gains nitrogen from the bat Kerivoula hardwickii while it roosts inside the pitchers. We hypothesized that N. hemsleyana is able to use urea from the bats' excrements. In fact, we demonstrate that 15N-enriched urea provided to Nepenthes pitchers is metabolized and its nitrogen is distributed within the plant. As ureases are necessary to degrade urea, these hydrolytic enzymes should be involved. We proved the presence and enzymatic activity of a urease for Nepenthes plant tissues. The corresponding urease cDNA from N. hemsleyana was isolated and functionally expressed. A comprehensive phylogenetic analysis for eukaryotic ureases, including Nepenthes and five other carnivorous plants' taxa, identified them as canonical ureases and reflects the plant phylogeny. Hence, this study reveals ureases as an emblematic example for an efficient, low-cost but high adaptive plasticity in plants while developing a further specialized lifestyle from carnivory to coprophagy

Communally breeding bats use physiological and behavioural adjustments to optimise daily energy expenditure

Small endotherms must change roosting and thermoregulatory behaviour in response to changes in ambient conditions if they are to achieve positive energy balance. In social species, for example many bats, energy expenditure is influenced by environmental conditions, such as ambient temperature, and also by social thermoregulation. Direct measurements of daily fluctuations in metabolic rates in response to ambient and behavioural variables in the field have not been technologically feasible until recently. During different reproductive periods, we investigated the relationships between ambient temperature, group size and energy expenditure in wild maternity colonies of Bechstein’s bats (Myotis bechsteinii). Bats used behavioural and physiological adjustments to regulate energy expenditure. Whether bats maintained normothermia or used torpor, the number of bats in the roosts as well changed with reproductive status and ambient temperature. During pregnancy and lactation, bats remained mostly normothermic and daily group sizes were relatively large, presumably to participate in the energetic benefits of social thermoregulation. In contrast, smaller groups were formed on days when bats used torpor, which occurred mostly during the post-lactation period. Thus, we were able to demonstrate on wild animals under natural conditions the significance of behavioural and physiological flexibility for optimal thermoregulatory behaviour in small endotherms

Information transfer about roosts in female Bechstein's bats: an experimental field study.

Information transfer among group members is believed to play an important part in the evolution of coloniality in both birds and bats. Although information transfer has received much scientific interest, field studies using experiments to test the underlying hypotheses are rare. We used a field experiment to test if communally breeding female Bechstein's bats (Myotis bechsteinii) exchange information regarding novel roosts. We supplied a wild colony, comprising 17 adult females of known relatedness, with pairs of suitable and unsuitable roosts and monitored the arrival of individuals marked with transponders (PIT-tags) over 2 years. As expected with information transfer, significantly more naive females were recruited towards suitable than towards unsuitable roosts. We conclude that information transfer about roosts has two functions: (i) it generates communal knowledge of a large set of roosts; and (ii) it aids avoidance of colony fission during roost switching. Both functions seem important in Bechstein's bats, in which colonies depend on many day roosts and where colony members live together for many years