Hibernacula microclimate and declines in overwintering bats during an outbreak of white‐nose syndrome near the northern range limit of infection in North America

We document white‐nose syndrome (WNS), a lethal disease of bats caused by the fungus Pseudogymnoascus destructans (Pd), and hibernacula microclimate in New Brunswick, Canada. Our study area represents a more northern region than is common for hibernacula microclimate investigations, providing insight as to how WNS may impact bats at higher latitudes. To determine the impact of the March 2011 arrival of Pd in New Brunswick and the role of hibernacula microclimate on overwintering bat mortality, we surveyed bat numbers at hibernacula twice a year from 2009 to 2015. We also collected data from iButton temperature loggers deployed at all sites and data from HOBO temperature and humidity loggers at three sites. Bat species found in New Brunswick hibernacula include Myotis lucifugus (Little Brown Bat) and M. septentrionalis (Northern Long‐eared Bat), with small numbers of Perimyotis subflavus (Tricolored Bat). All known hibernacula in the province were Pd‐positive with WNS‐positive bats by winter 2013. A 99% decrease in the overwintering bat population in New Brunswick was observed between 2011 and 2015. We did not observe P. subflavus during surveys 2013–2015 and the species appears to be extirpated from these sites. Bats did not appear to choose hibernacula based on winter temperatures, but dark zone (zone where no light penetrates) winter temperatures did not differ among our study sites. Winter dark zone temperatures were warmer and less variable than entrance or above ground temperatures. We observed visible Pd growth on hibernating bats in New Brunswick during early winter surveys (November), even though hibernacula temperatures were colder than optimum for in vitro Pd growth. This suggests that cold hibernacula temperatures encountered near the apparent northern range limit for Pd do not sufficiently slow fungal growth to prevent the onset of WNS and associated bat mortality over the winter.     

Estimating the spatial distribution of wintering little brown bat populations in the eastern United States

Depicting the spatial distribution of wildlife species is an important first step in developing management and conservation programs for particular species. Accurate representation of a species distribution is important for predicting the effects of climate change, land‐use change, management activities, disease, and other landscape‐level processes on wildlife populations. We developed models to estimate the spatial distribution of little brown bat (Myotis lucifugus) wintering populations in the United States east of the 100th meridian, based on known hibernacula locations. From this data, we developed several scenarios of wintering population counts per county that incorporated uncertainty in the spatial distribution of the hibernacula as well as uncertainty in the size of the current little brown bat population. We assessed the variability in our results resulting from effects of uncertainty. Despite considerable uncertainty in the known locations of overwintering little brown bats in the eastern United States, we believe that models accurately depicting the effects of the uncertainty are useful for making management decisions as these models are a coherent organization of the best available information.     

Development of conserved microsatellite markers of high cross-species utility in bat species (Vespertilionidae, Chiroptera, Mammalia)

Comparative ecological and behavioural studies of the widespread and diverse Vespertilionidae, which comprise almost 400 of the 1100 bat species, have been limited by the availability of markers. The potential of new methods for developing conserved microsatellite markers that possess enhanced cross-species utility has recently been illustrated in studies of birds. We have applied these methods to develop enhanced microsatellite markers for vespertilionid bats, in particular for the genus Myotis (103 species). We compared published bat microsatellites with their homologues in the genome sequence of the little brown bat, Myotis lucifugus, to create consensus sequences that were used to design candidate primer sets. Primer sets were then tested for amplification and polymorphism in 22 species of bat from nine of the largest families (including 11 Vespertilionidae). Of 46 loci tested, 33 were polymorphic, on average, in each of seven Myotis species tested, 20 in each of four species in other vespertilionid genera, and two in 11 nonvespertilionid species.     

Trophic resource partitioning drives fine‐scale coexistence in cryptic bat species

Understanding the processes that enable species coexistence has important implications for assessing how ecological systems will respond to global change. Morphology and functional similarity increase the potential for competition, and therefore, co‐occurring morphologically similar but genetically unique species are a good model system for testing coexistence mechanisms. We used DNA metabarcoding and high‐throughput sequencing to characterize for the first time the trophic ecology of two recently described cryptic bat species with parapatric ranges, Myotis escalerai and Myotis crypticus. We collected fecal samples from allopatric and sympatric regions and from syntopic and allotopic locations within the sympatric region to describe the diets both taxonomically and functionally and compare prey consumption with prey availability. The two bat species had highly similar diets characterized by high arthropod diversity, particularly Lepidoptera, Diptera and Araneae, and a high proportion of prey that is not volant at night, which points to extensive use of gleaning. Diet overlap at the prey item level was lower in syntopic populations, supporting trophic shift under fine‐scale co‐occurrence. Furthermore, the diet of M. escalerai had a marginally lower proportion of not nocturnally volant prey in syntopic populations, suggesting that the shift in diet may be driven by a change in foraging mode. Our findings suggest that fine‐scale coexistence mechanisms can have implications for maintaining broad‐scale diversity patterns. This study highlights the importance of including both allopatric and sympatric populations and choosing meaningful spatial scales for detecting ecological patterns. We conclude that a combination of high taxonomic resolution with a functional approach helps identify patterns of niche shift.     

Spatio-temporal population genetic structure of the parasitic mite Spinturnix bechsteini is shaped by its own demography and the social system of its bat host

Information about the population genetic structures of parasites is important for an understanding of parasite transmission pathways and ultimately the co-evolution with their hosts. If parasites cannot disperse independently of their hosts, a parasite's population structure will depend upon the host's spatial distribution. Geographical barriers affecting host dispersal can therefore lead to structured parasite populations. However, how the host's social system affects the genetic structure of parasite populations is largely unknown. We used mitochondrial DNA (mtDNA) to describe the spatio-temporal population structure of a contact-transmitted parasitic wing mite ( Spinturnix bechsteini ) and compared it to that of its social host, the Bechstein's bat ( Myotis bechsteinii ). We observed no genetic differentiation between mites living on different bats within a colony. This suggests that mites can move freely among bats of the same colony. As expected in case of restricted inter-colony dispersal, we observed a strong genetic differentiation of mites among demographically isolated bat colonies. In contrast, we found a strong genetic turnover between years when we investigated the temporal variation of mite haplotypes within colonies. This can be explained with mite dispersal occuring between colonies and bottlenecks of mite populations within colonies. The observed absence of isolation by distance could be the result from genetic drift and/or from mites dispersing even between remote bat colonies, whose members may meet at mating sites in autumn or in hibernacula in winter. Our data show that the population structure of this parasitic wing mite is influenced by its own demography and the peculiar social system of its bat host.     

毛腿鼠耳蝠、亚洲长翼蝠和栗鼠耳蝠斑驳白化现象

斑驳白化是一种先天性颜色失调表型,在翼手目中较为罕见。2016年5月至8月期间,分别在3个省份共发现3种存在斑驳白化现象蝙蝠。在河南省内乡县七里坪乡北湾村,发现1只怀孕雌性斑驳白化毛腿鼠耳蝠(Myotis fimbriatus),斑驳区域包括背部左侧区域及腹部左侧边缘一带。在陕西省柞水县下梁镇,发现1只怀孕雌性斑驳白化亚洲长翼蝠(Miniopterus fuliginosus),斑驳部位包括背部下端、腹部底端股骨边缘、左右股骨、尾骨及小部分尾膜区域。在云南省晋宁县双河乡法古甸村,发现2只斑驳白化雄性栗鼠耳蝠(Myotis badius),斑驳区域分别为背部左下侧和背颈部一侧,区域面积较小。其中,毛腿鼠耳蝠和栗鼠耳蝠的斑驳白化现象为国内首次报道。此外,通过测量蝙蝠体重、前臂长等体型参数,并与同种正常个体进行比较,发现斑驳白化亚洲长翼蝠体重偏大,1只斑驳白化栗鼠耳蝠前臂长偏大,其余斑驳白化蝙蝠体型数据均在正常范围内,表明斑驳白化现象对蝙蝠的正常生存与繁殖未造成严重影响。这为将来斑驳白化蝙蝠的生理生态研究提供科学依据。     

中国翼手类新记录--小巨足蝠

2003年9月在云南获得1号雌性蝙蝠标本,经鉴定为中国新记录——小巨足蝠(Myotis hasseltii),标本保存在中国科学院动物研究所。     

Diet and prey selection in the trawling long-fingered bat

The diet of the long-fingered bat Myotis capaccinii is poorly known, and there is no previously recorded information on this species' prey preferences. To investigate these subjects, we captured 51 individuals at a nursery cave in the Iberian Peninsula, from pre-breeding to post-lactation seasons. Each bat's diet composition was assessed by faecal content analysis and its foraging places (rivers, pools and channels) identified by radio-telemetry. To estimate prey availability, we sampled arthropods in the individual bats' identified foraging places and also emulated the bats' hunting technique. The bats' diet comprised of arthropods, dominated by small insects with aquatic larvae and flying adult phases. The most consumed taxon was Nematocera (mainly Chironomidae), including adults and pupae, which were also found to be the most abundant prey over water. Other frequently consumed prey were brachycerans, lepidopterans, arachnids, trichopterans and neuropterans. Diet proportions were compared with prey availability to infer a rank of preferences. The preferred prey were lepidopterans and arachnids, both having a terrestrial life cycle and a bigger size than any other taxa consumed. Without discarding the possible underestimation of prey's aerial availability, the observed preference pattern seems to be a consequence of selection for size more than for specific taxa. Apparently M. capaccinii efficiently exploit water-related prey according to availability when the bats hunt low over the water's surface, and are also able to take more profitable prey found higher in the air.     

Natterer's bats prefer foraging in broad-leaved woodlands and river corridors

We studied habitat selection by radio tracking Natterer's bats Myotis nattereri foraging in a grassland–woodland landscape. We tested the hypothesis that selection of foraging habitat is random at two levels: firstly, the selection of individual foraging ranges and secondly, the choice of foraging habitats made by individuals within these foraging ranges. Habitat selection was random at neither level. When selecting foraging ranges, bats maximized the area of semi-natural broad-leaved woodland and improved grassland and minimized that of dense coniferous plantations. During foraging, semi-natural broad-leaved woodland and river corridors were preferred, while dense coniferous plantations were avoided. Within individual foraging ranges, the intensity of foraging activity over river corridor habitat and semi-natural broad-leaved woodland was 8.2 and 3.8 times higher, respectively, than that over improved grassland. For successful management of Natterer's bat populations, semi-natural broad-leaved woodland should be retained. Clear felling of large blocks of native broad-leaved woodland should be avoided and conifers should not be used for reforestation. Tree cover along river banks should be encouraged and protected.