Northern Long-eared Bat Research Articles

Experimental Assessment of the Impacts of Northern Long-Eared Bats on OvipositingCulex(Diptera: Culicidae) Mosquitoes

The importance of predation as a mortality factor in adult mosquitoes has received only limited attention in the scientific literature. Despite the lack of consensus among researchers as to whether bats are important predators of mosquitoes, there have been no attempts to directly document the effect of bats on mosquito populations or behavior. We conducted an enclosure experiment to test the hypothesis that bats reduce the local abundance of ovipositing female mosquitoes by examining whether the northern long-eared bat (Myotis septentrionalis Trouessart) had an effect on Culex spp. (Diptera: Culicidae) oviposition, using naturally occurring mosquitoes, either through direct predation or trait mediated effects on mosquito behavior. We found a significant, 32% reduction in egg-laying activity associated with bat predation. Artificial oviposition habitats directly outside bat enclosures experienced no reduction in oviposition; we attributed the observed reduction in egg-laying activity to direct predation on ovipositing females by bats and not changes in mosquito behavior. In addition, we noted a decrease in the number of larval mosquitoes in enclosures exposed to bat predation. These results suggest the impact of aerial predators on pathogen transmission may be large, and warrants further scientific investigation.

Myotis septentrionalisTrouessart (Northern Long-Eared Bat) Records from the Coastal Plain of North Carolina

Abstract Myotis septentrionalis (Northern Long-eared Bat) is a small, insectivorous bat found in the eastern United States and Canada. Along the east coast, its range is thought to extend as far south as the Great Dismal Swamp in coastal Virginia. We captured six M. septentrionalis in the northern coastal plain region of North Carolina. Field identification was based on characters of ear and tragus length and confirmed with mitochondrial cytochrome c oxidase subunit I sequences. These captures signify the presence of a resident population of M. septentrionalis in the northern coastal plain of North Carolina. Future work is needed to document range limits and hibernation behavior of this species in the piedmont and coastal plain of North Carolina.

Using Hydrogen Isotopes to Assign Origins of Bats in the Eastern United States

Stable hydrogen isotopes (dDs) in metabolically inert tissues such as feathers and hair provide a set of endogenous markers that may be useful for establishing migratory connectivity in animals. We tested the assumption of a clear relationship between dD values of growing-season–weighted average precipitation (dDp) derived from 2 geographic information system (GIS) models or latitude (LAT) and dD values in bat hair (dDh), and examined intra- and interspecific variation in dDh of 4 bat species in the eastern United States. We analyzed 251 hair samples from 1 long-distance migrant (eastern red bat [Lasiurus borealis]) and 3 regional migrants (Indiana bat [Myotis sodalis], northern long-eared bat [M. septentrionalis], and little brown bat [M. lucifugus]) captured during the reproductive period (pregnancy and lactation) when bats are resident. LAT explained more of the variation in dDh than dDp derived from either of the GIS-based models, although 1 model of dDp performed better for some species. We found significant intraspecific differences in the relationships between dDh and LAT and between dDh and estimates of dDp derived from Bowen et al. (dDpB) for L. borealis, and significant variation in the regression equations of dDh and LAT and dDh and dDp among species for adult females and adult males. Stable hydrogen isotope analysis may be a valuable tool for studying migratory connectivity in bats, but significant intra- and interspecific variatio ni ndDh values suggests that pooling across sex and age categories and use of surrogate species should be avoided.

Summer Distribution and Status of the Bats of Prince Edward Island, Canada

Abstract The distribution and status of the bats of Prince Edward Island (PEI) is largely unknown. We addressed this information gap by compiling records from museums and published documents, and surveying for bats with traps and ultrasonic detectors during the summers of 2004 and 2005. Myotis lucifugus (Little Brown Bat) and M. septentrionalis (Northern Long-eared Bat) were the most abundant and widespread species of bats on the island. These species form maternity colonies, but the potential for there to be large natural hibernacula on the island is considered low. Lasiurus cinereus (Hoary Bat) is the only other species of bat that has been recorded on PEI, but its occurrence is rare. Diversity and abundance of bats on PEI may be limited by its northern insular geography, patchy distribution of forested areas, and lack of hibernacula. These limitations make protecting such resources on PEI and in neighboring provinces important for conserving the region's bat fauna.

Ectoparasite Prevalence in Myotis lucifugus and M. septentrionalis (Chiroptera: Vespertilionidae) During Fall Migration at Hayes Cave, Nova Scotia

Intra- and inter-specific variation in ectoparasite prevalence was characterized by collecting and identifying parasites on Myotis septentrionalis (Northern Long-eared Bat) and Myotis lucifugus (Little Brown Bat) returning to a large hibernaculum during the autumn migratory and reproductive swarming event in Nova Scotia, Canada. Unlike males, female bats in the region are colonial roosters during the summer, which may facilitate ectoparasite transfer. On bats captured at Hayes Cave, NS, there were at least four species of ectoparasites including Myodopsylla insignis (Siphonaptera: Ischnopsyllidae), Spinturnix americanus (Acarina: Spinturnicidae), Cimex adjunctus (Hemiptera: Cimicidae), and a larval Trombiculid mite, Leptotrombidium myotis (Acarina: Trombiculidae). Parasite prevalence was 30.6% and 27.8% for adult M. septentrionalis females and males, respectively, and 25.6% and 16.3% for adult female and male M. lucifugus, respectively. Myodopsylla insignis, S. americanus, C. adjunctus, and L. myotis all represent new host records on both bat species in Nova Scotia, while S. americanus and L. myotis are new species records for the province.

Range Extension of the Northern Long-eared Bat (Myotis septentrionalis) in the Yukon

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Intra-specific effects of forest loss on the distribution of the forest-dependent northern long-eared bat ( Myotis septentrionalis)

Forest fragmentation by the expansion of human activities is acknowledged as an important factor driving declines of forest species worldwide and quantitatively characterizing this trend is essential to understanding the response of populations of forest-dependent species. To examine the impacts of forest cover loss and changes in composition on forest-dependent bats, we examined the effects of these factors on the distribution of the northern long-eared bat ( Myotis septentrionalis) in a case study. We surveyed forest fragments in the forest-agricultural landscape of Prince Edward Island, Canada, to assess the occupancy of bats in fragments. Logistic regression and multimodel inference using Akaike’s information criteria were used to identify potentially important predictor variables influencing the distribution of the northern long-eared bat at the fragment and landscape level and quantified their effects. A compositional variable, area of deciduous stands, was found to be the best predictor of the presence of M. septentrionalis. We found the effects of fragmentation were greatest at the fragment level for females and at the landscape level for males. This case study emphasizes the importance of examining intra-specific resource selection in how it affects the response of a forest-dependent species to fragmentation.

Day roost characteristics of northern long-eared bats (Myotis septentrionalis) in relation to female reproductive status

In summer, females of most temperate bat species aggregate at maternity roosts, during which time females gestate, give birth, and wean offspring. These activities make the presence of suitable roosts critical for population persistence. Many studies have identified important roost tree characteristics by comparing roost trees to random trees. However, if bats select trees that facilitate either torpor use or maintenance of normothermic body temperatures relative to the energetic demands of reproduction, then it follows that roost tree characteristics may vary similarly. We compared variation in roost tree and site selection by lactating northern long-eared bats to the pre- and post-lactation periods. Scores from 2 principal components were the best predictors of the variation in roost selection. Relative to pre- and post-lactation periods lactating bat roost sites had a high and relatively open dominant canopy with low tree density (both coniferous and deciduous) and roost sites were situated high in tall trees. Our result demonstrates that when managing for bat roost trees, within-season variation in roost tree use should be considered.

Nonrandom association patterns at northern long-eared bat maternity roosts

Bats are among the most ecologically diverse mammalian orders. Most species live in groups for at least a portion of their life cycle and behavioural evidence suggests that individuals of many species live within complex nonrandomly assorting societies. However, rigorous quantitative characterizations of bat societies have been rare because of the difficulties inherent in studying these highly mobile, small, nocturnal animals. Here we use an automated monitoring system (PIT tags), telemetry, and recently developed analytical techniques to investigate the social organization (size, sexual composition, and spatiotemporal cohesion) and social structure (pattern of social interactions and relationships among individuals) of a colony of free-living northern long-eared bats, Myotis septentrionalis (Trouessart, 1897). Cluster analysis of HWI (half-weight association index) for all pairs and permutation tests indicate that colonies consist of multiple, nonrandomly assorting subgroups. A plot of the temporal persistence of relationships (standardized lagged association rate) showed that roosting groups dissociate over periods of approximately 10 days after which subsets of individuals remain associated throughout the summer roosting season. A model representing a two-levelled social structure of long-term (whole summer) and short-term (up to 10 days) acquaintances best fit the lagged association rate. Subgroups were most cohesive during the lactation period, but we found no evidence for the effects of minimum nightly temperature on subgroup cohesion.

Roost selection by male and female northern long-eared bats in a pine-dominated landscape

We radiotracked 17 male northern long-eared bats ( Myotis septentrionalis) to 43-day roosts and 23 females to 49-day roosts in the Ouachita Mountains of central Arkansas during summers 2000–2005. We compared characteristics of roost trees between males and females, and compared characteristics of sites surrounding roosts with random locations for each sex. Roosts were located in cavities, crevices, and under loose bark, primarily in snags; 85% of male and 95% of female roosts were in snags. Shortleaf pine ( Pinus echinata) was the most utilized tree species (71% of roosts) and both sexes preferred ( P < 0.05) pine snags over hardwood snags. Most (80%) snag roosts were in snags 10–24.9 cm dbh, but females roosted in snags of greater diameter than males and males tended to roost more in small (<10 cm dbh) hardwoods than females. Female roost sites were more likely to have fewer large (≥25 cm dbh) hardwoods, fewer midstory pines 5–9.9 cm dbh, fewer small (<10 cm dbh) hardwood snags, more overstory pines ≥25 cm dbh, and more pine snags <10 cm dbh than random sites. Most (55%) female roosts were located in pine-dominated stands that had undergone partial harvesting and midstory removal. Males were more likely to select sites with abundant large (≥25 cm dbh) overstory pines, fewer small overstory pines (10–24.9 cm dbh), and more large pine snags ≥10 cm dbh than random. More male roosts (42%) were in unharvested stands than female roosts (24%), and females roosted at sites with fewer midstory trees than males. Our results demonstrate the importance of pine snags as roosting habitat for northern long-eared bats and the importance to females of snags located in relatively open forests in the Ouachita Mountains during summer.

Northern Long-eared Bat, &lt;em&gt;Myotis septentrionalis&lt;/em&gt; (Chiroptera: Vespertilionidae), on Prince Edward Island: First Records of Occurrence and Over-Wintering

First occurrence of the Northern Long-eared Bat, Myotis septentrionalis, on Prince Edward Island is reported. A mixed-species hibernaculum of M. septentrionalis and the Little Brown Bat, M. lucifugus, is also described from southeastern Prince Edward Island. This is the first record of bats over-wintering in the province and the first time either species has been reported making use of a building as a hibernaculum.

Effect of Forest Structure and Fragmentation on Site Occupancy of Bat Species in Missouri Ozark Forests

Changes in structure and arrangement of forests may influence the distribution of bat communities by affecting roosting and foraging habitat. Using Anabat bat detectors, we determined presence of bat species at 316 sample plots in southeastern Missouri, USA, through qualitative identification of echolocation calls collected. We used maximum-likelihood estimation techniques incorporating detection probabilities into estimation of site occupancy by species of bats. We compared a priori models at 2 geographic scales using information theoretic methods. At the local-site scale, eastern pipistrelle (Pipistrellus subflavus) and red bat (Lasiurus borealis) occupancy was most influenced by structural characteristics of forested areas, whereas Indiana bats (Myotis sodalis) were influenced most by density of large-diameter snags that could provide roosting habitat. At the landscape scale, occupancy of Indiana bats was directly related to amount of nonforested land cover. Northern long-eared bat (M. septentrionalis) occupancy was inversely related to edge. These data describe implications of forest fragmentation and provide information that can be used when integrating forest-management practices into bat conservation.

Habitat Use by Forest Bats in South Carolina in Relation to Local, Stand, and Landscape Characteristics

Knowledge and understanding of bat habitat associations and the responses of bats to forest management are critical for effective bat conservation and management. Few studies have been conducted on bat habitat use in the southeast, despite the high number of endangered and sensitive species in the region. Our objective was to identify important local, stand, and landscape factors influencing bat habitat use in northwestern South Carolina, USA. We hypothesized that use would be greatest 1) at points with relatively sparse vegetation, 2) in early successional and mature stands, and 3) at points close to streams. We also predicted that species would exhibit different patterns of habitat use based on morphology. We placed Anabat II bat detectors at points located in 3 forest types and 3 age classes to record bats from May–August 2004 and 2005. We used an information theoretic approach to determine the variables that best predicted use by bats. Vegetation density at the sample point was the best predictor of overall bat presence in 2004. In 2005 vegetation density and distance to the closest road were the best predictors of overall bat use; the model containing age class also had good support. Bats were more likely to be recorded at points with sparse vegetation, farther from roads, and in early successional stands. Vegetation density was also the best predictor of habitat use by big brown bats (Eptesicus fuscus) and red bats (Lasiurus borealis); both species were far more likely to be recorded at points with sparse vegetation at the sample point. Eastern pipistrelles (Pipistrellus subflavus) were also more likely to be recorded at points with sparse vegetation and in early successional stands. The best predictors of northern long-eared bat (Myotis septentrionalis) habitat use were vegetation density and age class. Northern long-eared bats were more likely to be recorded at points with sparse vegetation and in mature stands. Our results suggest that early successional habitats and small openings and gaps within forest stands provide suitable commuting and foraging bat habitat in northwestern South Carolina. However, mature forests are also important for some species. Forest management practices that provide a variety of age classes across the landscape and that create gaps and openings within mid- and late-successional stands will likely provide suitable habitat for bats in the mountains of South Carolina.

Range Extent and Stand Selection for Roosting and Foraging in Forest-Dwelling Northern Long-Eared Bats and Little Brown Bats in the Greater Fundy Ecosystem, New Brunswick

To understand bat biology and appreciate their dependence on and role within forested ecosystems, the biological resolution at which studies are directed must elucidate species and gender patterns. We studied species- and gender-specific aspects of summer range extent and stand selection in northern long-eared bats (Myotis septentrionalis) and little brown bats (M. lucifugus) in the Greater Fundy Ecosystem, New Brunswick, Canada, using trapping, radiotelemetry, and ultrasonic monitoring. Our results suggested that this 2-species system is comprised of 4 ecologically distinct groups with respect to site selection and range extent for roosting and foraging. All bats exhibited an affinity to specific roosting areas. Myotis septentrionalis roosted and foraged in the forest interior. The roosting and foraging areas for females were 6.1 times and 3.4 times larger, respectively, than for males. Both genders foraged in site types in proportion to their availability. Myotis lucifugus females roosted in buildings outside the core study area, and those captured in the forested landscape were transients. Compared to male and female M. septentrionalis, male M. lucifugus had intermediate-sized roosting areas but the largest foraging areas. Water sites were selected during foraging more than expected. Bat foraging activity, measured acoustically at 8 site types, was greatest at lakes and least above the forest canopy. Male M. lucifugus activity levels were positively associated with temperature and the amount of mature coniferous forest and water within 1 km of the sampling site, and they were negatively associated with the amount of mature deciduous forest within 1 km of the site. Our results suggested that understanding gender effects is crucial for accurate characterization of forest bat habitats. Studies of bats that combine data for genders, species, or guilds may produce spurious results and may be of minimal value for, or actually hinder, bat conservation and management programs.

First Records of the Northern Long-eared Bat, &lt;em&gt;Myotis septentrionalis&lt;/em&gt;, in the Yukon Territory

Three adult male Northern Long-eared Bats, Myotis septentrionalis, were captured in mist nets in July 2004 in the LaBiche River Valley, southeastern Yukon. These are the first records of M. septentrionalis in the Yukon. Further survey work is needed to delineate the extent of the range and population structure of this and other species of bats in northwestern North America.

The adaptive function of tiger moth clicks against echolocating bats: an experimental and synthetic approach

We studied the efficiency and effects of the multiple sensory cues of tiger moths on echolocating bats. We used the northern long-eared bat, Myotis septentrionalis, a purported moth specialist that takes surface-bound prey (gleaning) and airborne prey (aerial hawking), and the dogbane tiger moth, Cycnia tenera, an eared species unpalatable to bats that possesses conspicuous colouration and sound-producing organs (tymbals). This is the first study to investigate the interaction of tiger moths and wild-caught bats under conditions mimicking those found in nature and to demand the use of both aerial hawking and gleaning strategies by bats. Further, it is the first to report spectrograms of the sounds produced by tiger moths while under aerial attack by echolocating bats. During both aerial hawking and gleaning trials, all muted C. tenera and perched intact C. tenera were attacked by M. septentrionalis, indicating that M. septentrionalis did not discriminate C. tenera from palatable moths based on potential echoic and/or non-auditory cues. Intact C. tenera were attacked significantly less often than muted C. tenera during aerial hawking attacks: tymbal clicks were therefore an effective deterrent in an aerial hawking context. During gleaning attacks, intact and muted C. tenera were always attacked and suffered similar mortality rates, suggesting that while handling prey this bat uses primarily chemical signals. Our results also show that C. tenera temporally matches the onset of click production to the ;approach phase' echolocation calls produced by aerial hawking attacking bats and that clicks themselves influence the echolocation behaviour of attacking bats. In the context of past research, these findings support the hypotheses that the clicks of arctiid moths are both an active defence (through echolocation disruption) and a reliable indicator of chemical defence against aerial-hawking bats. We suggest these signals are specialized for an aerial context.

Roost tree use by maternity colonies of Indiana bats and northern long-eared bats in southern Illinois

Roost trees used by female Indiana bats ( Myotis sodalis), a federally endangered species, and sympatric northern long-eared bats ( Myotis septentrionalis) at two locations in southern Illinois greatly impacted by past flooding were located using radiotelemetry. For 30 Indiana bats, we located 49 roosts in 7 species of trees. Green ash snags ( Fraxinus pennsylvanica) and pin oak snags ( Quercus palustris) were used more than expected and sweetgum snags ( Liquidambar styraciflua) less than expected based on availability. Ten adult female northern long-eared bats were tracked to 19 different trees of 5 species. We used logistic regression to predict use of roost versus random trees for both species, and to compare roosts of Indiana bats versus northern long-eared bats. Indiana bats typically roosted in areas of low vegetative obstruction (clutter) on the forest edge ( χ 2 = 10.28, d.f. = 2, P = 0.006). Compared to random trees, roosts of northern long-eared bats were within intact forests ( χ 2 = 10.56, d.f. = 1, P = 0.001). Amount of obstruction and decay differed; roosts of M. sodalis typically were less cluttered and more decayed than those of M. septentrionalis ( χ 2 = 38.63, d.f. = 2, P < 0.001). Indiana bats roosted almost exclusively under exfoliating bark of bottomland snags, whereas northern long-eared bats also made extensive use of cavities and crevices. Indiana bats cannot be expected to remain in an area indefinitely if snag creation is not sustained, and natural forest succession should be considered in long-term management of this endangered species.

Roost site selection by forest-dwelling male Myotis in central Ontario, Canada

We used radiotelemetry and random exit counts to determine roost site selection by male northern long-eared bats ( Myotis septentrionalis) and unidentified Myotis, either northern long-eared or little brown bats ( M. lucifugus) in a conifer-dominated, mixedwood forest landscape in central Ontario, Canada. We compared the characteristics of snags used as roosts ( n = 26), with randomly located snags and random points ( n = 52 and 50, respectively), at three spatial scales: focal tree, surrounding forest, and landscape. Snags used as roost sites by these bats differed from random snags for 19 of the 23 variables measured ( P < 0.05). Logistic regression models were derived which suggested that the bats selected large snags, in open canopies, of intermediate stages of decay, that were located in upland areas, but away from water bodies. Bats may have selected roost sites for their thermal advantage in the mornings, as most used cavities or bark on the south and east sides of snags. To ensure that snags of appropriate characteristics persist for these two species of Myotis, forest managers in the northern Great Lakes forest region should retain, and manage for, large white pine ( Pinus strobus) and trembling aspen ( Populus tremuloides) snags at sites in forests that meet these criteria. Such a regime is possible under a selection harvest that is normally practiced in these mixedwood forest types.

INTERSPECIFIC AND INTERSEXUAL VARIATION IN ROOST-SITE SELECTION OF NORTHERN LONG-EARED AND LITTLE BROWN BATS IN THE GREATER FUNDY NATIONAL PARK ECOSYSTEM

Abstract Although only 2 bat species are common in the Greater Fundy National Park Ecosystem of New Brunswick, Canada, 4 distinct groups occur in terms of roost-site selection due to sexual segregation. We found that female northern long-eared bats (Myotis septentrionalis) roosted alone or as part of maternity colonies in mature, shade-tolerant deciduous stands. A roost site was 24 times more likely to be in a shade-tolerant deciduous tree than a coniferous tree, and trees in the mid-decay classes were 5.2 times more likely to be used than live or recently dead trees. Male northern long-eared bats roosted alone in coniferous stands or conifer-dominated mixedwood stands, and they selected roost trees that were in the mid-decay stages. Trees in mid-decay stages were selected more than twice as often as trees at the early or late stages of decay. For every 10% increase in the proportion of coniferous trees in the plot, the chances of a male northern long-eared bat roosting in the plot increased 1.5 times. Fe...

West nile virus antibodies in bats from New Jersey and New York.

Eighty-three serum samples were obtained from big brown (Eptesicus fuscus), little brown (Myotis lucifugus), and northern long-eared (Myotis septentriotalis) bats (Chiroptera: Vespertilionidae), from New Jersey and New York (USA) between July and October 2002. Samples were analyzed for neutralizing antibodies to West Nile virus (WNV) and St. Louis encephalitis (SLE) virus. One little brown bat and one northern long-eared bat tested positive for WNV neutralizing antibodies. No bats had antibodies to SLE virus. This was the first large-scale investigation of WNV infection in bats in New Jersey. Additional work is needed to determine the effects of WNV on bat populations.