Hibernation temperature-dependent Pseudogymnoascus destructans infection intensity in Palearctic bats.

White-nose syndrome (WNS) is a fungal disease caused by Pseudogymnoascus destructans that is devastating to Nearctic bat populations but tolerated by Palearctic bats. Temperature is a factor known to be important for fungal growth and bat choice of hibernation. Here we investigated the effect of temperature on the pathogenic fungal growth in the wild across the Palearctic. We modelled body surface temperature of bats with respect to fungal infection intensity and disease severity and were able to relate this to the mean annual surface temperature at the site. Bats that hibernated at lower temperatures had less fungal growth and fewer skin lesions on their wings. Contrary to expectation derived from laboratory P. destructans culture experiments, natural infection intensity peaked between 5 and 6°C and decreased at warmer hibernating temperature. We made predictive maps based on bat species distributions, temperature and infection intensity and disease severity data to determine not only where P. destructans will be found but also where the infection will be invasive to bats across the Palearctic. Together these data highlight the mechanistic model of the interplay between environmental and biological factors, which determine progression in a wildlife disease.

Hidden diversity in Senegalese bats and associated findings in the systematics of the family Vespertilionidae.

INTRODUCTION: The Vespertilionidae is the largest family of bats, characterized by high occurrence of morphologically convergent groups, which impedes the study of their evolutionary history. The situation is even more complicated in the tropics, where certain regions remain under-sampled. RESULTS: Two hundred and thirteen vespertilionid bats from Senegal (West Africa) were studied with the use of non-differentially stained karyotypes and multi-locus sequence data analysed with maximum likelihood and Bayesian methods. These bats were identified as 10 different taxa, five of which were distinctive from their nominate species (Pipistrellus hesperidus, Nycticeinops schlieffenii, Scotoecus hirundo, Neoromicia nana and N. somalica), based on both karyotypes and molecular data. These five cryptic taxa are unrelated, suggesting that these West African populations have long been isolated from other African regions. Additionally, we phylogenetically analysed 166 vespertilionid taxa from localities worldwide using GenBank data (some 80% of the genera of the family) and 14 representatives of closely related groups, together with our Senegalese specimens. The systematic position of several taxa differed from previous studies and the tribes Pipistrellini and Vespertilionini were redefined. The African Pipistrellus rueppellii was basal to the Pipistrellus/Nyctalus clade and the Oriental species Glischropus tylopus was basal to the East Asian pipistrelles within the tribe Pipistrellini. The African genus Neoromicia was confirmed to be diphyletic. Based on GenBank data, Eptesicus was polyphyletic, with the Asian E. nasutus and E. dimissus both supported as phylogenetically distinct from the Eptesicus clade. The subfamily Scotophilinae was confirmed as one of the basal branches of Vespertilionidae. CONCLUSIONS: New taxa and new systematic arrangements show that there is still much to resolve in the vespertilionids and that West Africa is a biogeographic hotspot with more diversity to be discovered.

Complex patterns of host switching in New World arenaviruses.

We empirically tested the long-standing hypothesis of codivergence of New World arenaviruses (NWA) with their hosts. We constructed phylogenies for NWA and all known hosts and used them in reconciliation analyses. We also constructed a phylogenetic tree of all Sigmodontinae and Neotominae rodents and tested whether viral-host associations were phylogenetically clustered. We determined host geographical overlap to determine to what extent opportunity to switch hosts was limited by host relatedness or physical proximity. With the exception of viruses from North America, no phylogenetically codivergent pattern between NWA and their hosts was found. We found that different virus clades were clustered differently and that Clade B with members pathogenic to humans was randomly distributed across the rodent phylogeny. Furthermore, viral relatedness within Clade B was significantly explained by the geographic overlap of their hosts' ranges rather than host relatedness, indicating that they are capable of host switching opportunistically. This has important bearings on their potential to become panzootic. Together, these analyses suggest that NWA have not codiverged with their hosts and instead have evolved predominantly via host switching.

Histopathology confirms white-nose syndrome in bats in Europe.

White-nose syndrome, associated with the fungal skin infection geomycosis, caused regional population collapse in bats in North America. Our results, based on histopathology, show the presence of white-nose syndrome in Europe. Dermatohistopathology on two bats (Myotis myotis) found dead in March 2010 with geomycosis in the Czech Republic had characteristics resembling Geomyces destructans infection in bats confirmed with white-nose syndrome in US hibernacula. In addition, a live M. myotis, biopsied for histopathology during hibernation in April 2011, had typical fungal infection with cupping erosion and invasion of muzzle skin diagnostic for white-nose syndrome and conidiospores identical to G. destructans that were genetically confirmed as G. destructans.

Variation in phenotype, parasite load and male competitive ability across a cryptic hybrid zone.

BACKGROUND: Molecular genetic studies are revealing an increasing number of cryptic lineages or species, which are highly genetically divergent but apparently cannot be distinguished morphologically. This observation gives rise to three important questions: 1) have these cryptic lineages diverged in phenotypic traits that may not be obvious to humans; 2) when cryptic lineages come into secondary contact, what are the evolutionary consequences: stable co-existence, replacement, admixture or differentiation and 3) what processes influence the evolutionary dynamics of these secondary contact zones? METHODOLOGY/PRINCIPAL FINDINGS: To address these questions, we first tested whether males of the Iberian lizard Lacerta schreiberi from two highly genetically divergent, yet morphologically cryptic lineages on either side of an east-west secondary contact could be differentiated based on detailed analysis of morphology, coloration and parasite load. Next, we tested whether these differences could be driven by pre-copulatory intra-sexual selection (male-male competition). Compared to eastern males, western males had fewer parasites, were in better body condition and were more intensely coloured. Although subtle environmental variation across the hybrid zone could explain the differences in parasite load and body condition, these were uncorrelated with colour expression, suggesting that the differences in coloration reflect heritable divergence. The lineages did not differ in their aggressive behaviour or competitive ability. However, body size, which predicted male aggressiveness, was positively correlated with the colour traits that differed between genetic backgrounds. CONCLUSIONS/SIGNIFICANCE: Our study confirms that these cryptic lineages differ in several aspects that are likely to influence fitness. Although there were no clear differences in male competitive ability, our results suggest a potential indirect role for intra-sexual selection. Specifically, if lizards use the colour traits that differ between genetic backgrounds to assess the size of potential rivals or mates, the resulting fitness differential favouring western males could result in net male-mediated gene flow from west to east across the current hybrid zone.