Perimyotis Research Articles

SPECIES DIVERSITY, REPRODUCTION, AND SEX RATIOS OF BATS IN MANAGED PINE FOREST LANDSCAPES OF MISSISSIPPI

Information on bat diversity, reproduction, and sex ratios in the southeastern United States is limited, particulary in managed pine (Pinus spp.) forests. Such information is needed if regional forest managers are to consider bats within their overall management plans. Therefore, I mist-netted over water to document bat species richness, diversity, reproduction, and sex ratios in landscapes of managed loblolly pine (Pinus taeda) forests of eastern Mississippi from late April to early September, 1998–2000. In 53 survey nights, I captured 284 bats of six species [eastern red bat (Lasiurus borealis), evening bat (Nycticeius humeralis), Seminole bat (L. seminolus), eastern pipistrelle (Pipistrellus subflavus), hoary bat (L. cinereus), and southeastern myotis (Myotis austroriparius)]. Simpson's diversity index was 0.36 for all years combined. Managed pine forest landscapes in this study appeared to provide suitable habitat for bats. Overall, 84% of captured female bats displayed reproductive activity, indicating that habitat quality was likely sufficient for successful reproduction. Sex ratios for red bats and eastern pipistrelles changed from male-dominated as juveniles to female-dominated as adults. Seminole bats displayed sex ratios skewed toward females as juveniles and adults. Evening bat sex ratios were skewed toward females as juveniles, but nearly even between sexes as adults. Future surveys should include simultaneous recording of bat echolocation calls, bridge surveys, and winter surveys to determine how managed pine forest landscapes contribute to conservation of bat communities in the southeastern United States.

Trends in national surveillance for rabies among bats in the United States (1993-2000).

To describe surveillance trends and epidemiologic features of rabies in bats in the United States, focusing on 3 bat species primarily associated with variants of the rabies virus that affect humans. Retrospective study. 31,380 bats. Data on rabies for bats identified to species and reported by state laboratories from 1993 to 2000 were analyzed, focusing on silver-haired, eastern pipistrelle, and Brazilian free-tailed bats. Categoric variables were derived from other provided information. Data were reported from 37 states during the study interval; complete species-specific data were not reported by any state for the entire interval. Bats primarily associated with rabies virus variants affecting humans were more likely to yield positive test results for rabies (22.7%), compared with all other bats (5.5%) in most seasons and from most regions of the United States. However, certain other bat species had higher percentages of positive results. Risk of positive results was highest in the fall and highest among bats originating in the southwestern United States. Increased risk of rabies among certain groups of bat species was consistently found across seasons and most geographic regions of the United States. Results were in general agreement with those of previous studies conducted within smaller geographic regions. There are ongoing efforts to improve surveillance of rabies in bats, although surveillance is incomplete in some regions.

Emerging Pattern of Rabies Deaths and Increased Viral Infectivity

Most human rabies deaths in the United States can be attributed to unrecognized exposures to rabies viruses associated with bats, particularly those associated with two infrequently encountered bat species (Lasionycteris noctivagans and Pipistrellus subflavus). These human rabies cases tend to cluster in the southeastern and northwestern United States. In these regions, most rabies deaths associated with bats in nonhuman terrestrial mammals are also associated with virus variants specific to these two bat species rather than more common bat species; outside of these regions, more common bat rabies viruses contribute to most transmissions. The preponderance of rabies deaths connected with the two uncommon L. noctivagans and P. subflavus bat rabies viruses is best explained by their evolution of increased viral infectivity.

Emerging epidemiology of bat-associated cryptic cases of rabies in humans in the United States.

In the United States, during the past half-century, the number of humans to die of rabies dramatically decreased to an average of 1-2 per year. Although the number of deaths is low, most deaths occur because individuals are unaware that they had been exposed to and infected with rabies virus, and, therefore, they do not seek effective postexposure treatment. Molecular epidemiological studies have linked most of these cryptic rabies exposures to rabies virus variants associated with insectivorous bats. In particular, virus variants associated with 2 relatively reclusive species, the silver-haired bat (Lasionycteris noctivagans) and the eastern pipistrelle (Pipistrellus subflavus), are the unexpected culprits of most cryptic cases of rabies in humans.

PLACEMENT OF NETS FOR BATS: EFFECTS ON PERCEIVED FAUNA

We used mistnets to survey bats at 41 sites throughout the Shawnee National Forest in southern Illinois during the summers of 1999 and 2000. Unlike most previous studies, we placed nets in the interior of forest stands as well as the more typical placement along edge habitats associated with water. We captured 417 individual bats representing 10 species. Of these, 168 individuals (40.3%) and 8 species were collected in interior forest. Northern long-eared bats (Myotis septentrionalis) were caught significantly more often in interior forest, whereas red bats (Lasiurus borealis), eastern pipistrelles (Pipistrellus subflavus), and big brown bats (Eptesicus fuscus) were netted more often in edge habitats. In contiguous forest, especially within the geographic range of M. septentrionalis, a more accurate measure of bat diversity and relative abundance is obtained by placing nets in interior forest as well as edge habitats.

In brief

If you wake up to find a bat in the room, skip the priest and call the doctor, advises Robert Gibbons of the Walter Reed Army Institute of Research in Maryland, USA. As reported in a study recently published in Annals of Emergency Medicine, most human cases of rabies in the USA are caused by bat bites. People are bitten by bats only rarely, but when they are, the bites often go unrecognized. Because the most common bats in the United States are so small, their bites could conceivably be mistaken for spider bites, bee stings or pricks from thorns. The tiny silver-haired and eastern pipistrelle bats are also easy to miss, as they are fairly independent and do not form large colonies. Gibbons also concludes that people are unlikely to catch rabies indirectly from bats, either through aerosols or by being bitten by infected domestic animals. AV

STATUS OF THE EASTERN PIPISTRELLE (PIPISTRELLUS SUBFLAVUS) (CHIROPTERA: VESPERTILIONIDAE) IN NEW BRUNSWICK

Abstract Five new specimens and 49 echolocation records (< 0.2% of all echolocation sequences recorded) identified as eastern pipistrelle, Pipistrellus subflavus (F. Cuvier) are documented in New Brunswick. Previously this bat was known in New Brunswick from a single specimen discovered over-wintering in a natural limestone cave. New records show the eastern pipistrelle confined to the Fundy coast of New Brunswick, but over-wintering in both natural caves and an abandoned graphite mine. In New Brunswick, where they have been recorded hibernating with congregations of Myotis species, eastern pipistrelles comprised less than 1.5% of the bats present. Pipistrelle echolocation sequences that are the first reports for the species outside winter roosting habitat in New Brunswick indicate a strong preference for feeding over water. Both echolocation sequences and specimen records suggest that the eastern pipistrelle is of very rare but regular occurrence in southern coastal New Brunswick. The species' provincial...

POPULATION TRENDS OF WINTERING BATS IN VERMONT

We report the results of all readily available inventories of wintering bats in Vermont. Surveys at 23 hibernacula were compiled from the literature and unpublished data of numerous biologists and cavers. The earliest Vermont records date back to 1934. Only five hibernacula were systematically surveyed for more than 45 years. Despite data limitations, several trends have emerged. Since the 1930s, wintering populations of Myotis sodalis have dramatically declined; wintering populations of M. lucifugus have increased; and wintering populations of all other Vermont species (M. leibii, M. septentrionalis, Eptesicus fuscus, and Pipistrellus subflavus) have remained small.

Use and Selection of Winter Hibernacula by the Eastern Pipistrelle (Pipistrellus subflavus) in Texas

Use and Selection of Winter Hibernacula by the Eastern Pipistrelle (Pipistrellus subflavus) in Texas

USE AND SELECTION OF WINTER HIBERNACULA BY THE EASTERN PIPISTRELLE (PIPISTRELLUS SUBFLAVUS) IN TEXAS

Use and selection of winter hibernacula by the eastern pipistrelle (Pipistrellus subflavus) in Texas

Mammalian reservoirs and epidemiology of rabies diagnosed in human beings in the United States, 1981-1998.

Between 1981 and 1998, 37 cases of rabies were diagnosed in human beings in the United States. Information directly linking the cause of infection to animal bite was available for only eight of these cases. Indirect incrimination of the vector by analysis of cDNA sequences obtained by reverse transcriptase polymerase chain reaction of samples indicated that for all cases (12/12) believed to have been acquired in foreign countries, variants of the rabies virus (VRVs) associated with dogs (7/12 involved known bite histories) were the cause of the rabies infections. In contrast, VRVs associated with bats (bat-associated VRVs or BAVs) were implicated as the cause of 88% (22/25) of infections believed to have been acquired within the United States (1/22 involved known bite histories). Sequence analyses revealed that a single BAV (Ln/Ps), associated with rabid silver-haired (Lasionycteris noctivagans) and Eastern pipistrelle (Pipistrellus subflavus) bats, was implicated in 73% (16/22) of bat-associated infections. Silver-haired bats are predominantly solitary and migratory. Eastern pipistrelle bats may occur individually or in small clusters. Both species are only infrequently submitted for rabies testing. Unrecognized bites and unique properties of the Ln/Ps BAV may explain its association with the majority of rabies infections in human beings in the United States.

Rabies surveillance in the United States during 1998

During 1998, 49 states, the District of Columbia, and Puerto Rico reported 7,961 cases of rabies in nonhuman animals and 1 case in a human being to the Centers for Disease Control and Prevention, a decrease of 6.5% from 8,509 cases in nonhuman animals and 4 cases in human beings reported in 1997. More than 92% (7,358 cases) were in wild animals, whereas &gt; 7.5% (603 cases) were in domestic species (compared with 93% in wild animals and 7% in domestic species in 1997). Decreases were evident in all of the major contributing species groups, with the exception of skunks and bats. The relative contributions of the major groups to the total reported for 1998 were raccoons (44.0%; 3,502 cases), skunks (28.5%; 2,272), bats (12.5%; 992), foxes (5.5%; 435), cats (3.5%; 282), cattle (1.5%; 116), and dogs (11.5%; 113). No further discernable westward extension of the epizootic of rabies in raccoons in Ohio was reported. Twelve of the 19 states enzootic for the raccoon variant of the rabies virus and the District of Columbia reported decreased numbers of cases of rabies during 1998, compared with 13 states and the District of Columbia that reported increases during 1997. Three states, Rhode Island (143.2%), Massachusetts (77.2%), and New Hampshire (69.4%), reported increases of &gt; 50% during 1998, compared with totals reported for 1997. In Texas, the number of cases of rabies associated with enzootic canine variants of the rabies virus remained greatly diminished; however, overall totals of reported cases of rabies increased in Texas and 12 other states where skunks are the major terrestrial reservoir of rabies. At the national level, the total of 82 reported cases of rabies among horses and mules was greater than that reported for any year since 1981 (88 cases) and represented a 74.5% increase, compared with the total for 1997. The 992 cases of rabies reported in bats during 1998 were the greatest proportionate contribution by bats since 1990. Reported cases of rabies in cats (282), dogs (113), and cattle (116) decreased 6.0%, 10.3%, and 4.9%, respectively. One indigenously acquired case of rabies reported in a human being during 1998 was the result of infection with a rabies virus variant associated with silver-haired and eastern pipistrelle bats.

Life History and Roost Switching in Six Summer Colonies of Eastern Pipistrelles in Buildings

Summer colonies of the eastern pipistrelle, Pipistrellus subflavus , in six different buildings in Indiana were studied by the owners of the buildings. Colonies generally started forming from 13 to 29 April. Size of the colony increased gradually and reached a maximum of 7 to 29 adults ( X = 15 ± 7 SD, n = 18) from 26 April to 7 June. Births occurred from 30 May to 11 July, but most young were born from 12 June to 1 July. Juveniles apparently became volant ca. 4 weeks of age and foraged with their mothers for ca. 1 week. Adults often abandoned maternity roosts soon after weaning, but young remained longer. There was considerable daily variation in the number of bats in a given colony, and sometimes the entire colony disappeared, even when flightless young were present, suggesting that each colony was using more than one roost.

Variation in size at birth and post‐natal growth in the insectivorous bat Pipistrellus subflavus (Chiroptera: Vespertilionidae)

AbstractWe describe the size and developmental state at birth, examine factors which influence intra‐ and inter‐year variation in post‐natal growth, and derive age‐predictive equations and logistic growth parameters for the eastern pipistrelle bat, Pipistrellus subflavus. Ambient and roost temperature and insect abundance were lowest, and precipitation highest, before and during the post‐natal growth period in 1982, as compared to 1981. We found no sex differences in the size of pups at birth or in post‐natal growth rates in a given year; however, body mass and length of forearm of neonates differed significantly between years, being smaller in 1982 than in 1981. During the first two weeks of post‐natal growth in both years, the body mass and length of forearm of pups increased linearly at mean rates of 0.15 g.day−1 and 1.12 mm.day−1, respectively. Post‐natal growth rates for length of forearm and body mass were the same during the early linear phase of growth, but the intercept for body mass was less and growth trajectories were more variable in 1982. Length of forearm was the least variable and thus most reliable character for estimating age of P. subflavus pups during the first 14 days of post‐natal growth. When length of forearm was used in combination with mean changes in the length of the fourth metacarpal‐phalangeal epiphyseal gap, we derived reliable age‐estimation equations ranging from 1 to 45 days. Litter size averaged 1.96 and 1.93 at birth, but this was reduced to one by the time pups became volant. At birth, litter mass represented 44, and 54% of the post‐partum mass of females in 1981 and 1982, respectively. This maternal effort during pregnancy is among the highest reported for bats. At weaning, the body mass of pups approached 80% of adult post‐partum body mass, and the length of forearm exceeded 90% of adult female size. Our results suggest that size at birth and post‐natal growth are influenced by ambient and roost temperature, rainfall, and the quantity of insects available to pregnant and lactating females. Thus, energetic constraints on both mothers and pups can lead to inter‐year and inter‐individual differences in maternal effort and post‐natal growth of pups.

Variation in size at birth and post-natal growth in the insectivorous bat Pipistrellus subflavus (Chiroptera: Vespertilionidae)

Variation in size at birth and post-natal growth in the insectivorous bat Pipistrellus subflavus (Chiroptera: Vespertilionidae)

Day-roosting activity budgets of the eastern pipistrelle bat, Pipistrellus subflavus (Chiroptera: Vespertilionidae)

Daily and seasonal activity budgets of adult female eastern pipistrelle bats, Pipistrellus subflavus, were quantified at a maternity colony in eastern Massachusetts. Ambient and roost temperatures were recorded. Activities of roosting bats were monitored using an infrared-sensitive video camera. Scan sampling was used to analyze video records taken at weekly intervals from mid-May to late July 1989. Analysis of day-roosting indicates that adult females spend an average of 77% of their time at rest, 16% alert, 7% grooming, and &lt; 1% crawling. Bats were most active immediately following their morning return to the day-roost and just prior to their departure at dusk. Periodic bouts of activity throughout the day were usually associated with urination and (or) defecation, mother–pup interactions, and movements in response to changes in roost temperature. Females were significantly more active in mortise roosts than when roosting on the open ridgepole, probably because fluctuations in temperature in mortises were smaller. As the season progressed, the overall time that bats spent resting decreased from 86 to 70%, whereas time spent alert increased from 9 to 24%; weekly fluctuations in the incidence of grooming and crawling showed no consistent seasonal trends. Roost temperature, time of day, and date explained significant amounts of variation in both daily and seasonal activity budgets. Females rested significantly less and were more alert after young were born than before, although time spent grooming and crawling did not differ significantly between the pre- and post-partum periods. Our findings for P. subflavus generally corroborate activity budgets previously reported for the little brown bat (Myotis lucifugus).

Bats and Barometric Pressure: Conserving Limited Energy and Tracking Insects from the Roost

Studies were conducted to assess the response of a seasonal cave-dwelling bat and its insect prey to natural and experimental changes in barometric pressure. The Eastern Pipistrelle, Pipistrellus subflavus, tracks barometric pressure metabolically. Eastern Pipistrelles potentially use pressure as a cue for predicting the relative abundance of aerial insect prey outside the roost. Barometric pressure tracking affords these bats an opportunity to conserve limited energy and make appropriate foraging decisions. Barometric pressure tracking is viewed as an alternative evolutionary strategy to torpor and may be a widespread phenomenon among insect-feeding bats that roost deep within caves.

Observations on the pineal gland of the big brown bat, Eptesicus fucus: possible correlation of melanin intensification with constant darkness.

Our initial observation of the macroscopically pigmented pineal gland of the big brown bat, Eptesicus fuscus, led to this study. Information has been lacking on pigmentation in the pineal and its significance in mammals in general and bats in particular. This report begins to address this situation. Bats were examined both in the wild and after exposure to various experimental conditions. The pineals were examined macroscopically as well as with light and electron microscopy. The pigment was identified as melanin by its color, the ultrastructure of its granules, and their reaction with hydrogen peroxide. Gross observations showed the pineals to be variably pigmented, which were subjectively scored from unpigmented to heavily pigmented. Pineals from bats exposed to a continuous 24 h light regimen or those from a summer population contained very little, if any, externally visible melanin. Such pineals are considered unpigmented in this study. In contrast, pineals from 74% of 156 animals taken together, either subjected to constant darkness or hibernation (simulated or natural), exhibited very heavily pigmented pineals. The pigment in these cases even extended to the juxtapineal meningeal covering. The pineal was pigmented even in a newborn Eptesicus. The pineal pigmentation in the big brown bat appears to intensify with constant darkness and may vary seasonally. The observation of macroscopically pigmented pineals in some other bats (Myotis lucifugus, Pipistrellus subflavus, and Lasiurus borealis) suggests that this phenomenon may be of taxonomic value for the family Vespertilionidae (Order Chiroptera).

A Novel Hibernaculum and Noteworthy Records of the Indiana Bat and Eastern Pipistrelle (Chiroptera: Vespertilionidae)

A Novel Hibernaculum and Noteworthy Records of the Indiana Bat and Eastern Pipistrelle (Chiroptera: Vespertilionidae)

Synonymy of Longibucca eptesica with Longibucca lasiura (Nematoda: Rhabditoidea) and New Host and Geographic Records

The genus Longibucca Chitwood, 1933 (Nematoda: Rhabditoidea) is reviewed based on examination of museum and adult specimens collected from 4 species of bats (Myotis lucifugus, Myotis ciliolabrum, Eptesicus fuscus, and Lasionycteris noctivagans) in Alberta, Canada. Two species are considered valid, namely Longibucca vivipara Chitwood, 1933, and Longibucca lasiura McIntosh and Chitwood, 1934. Longibucca eptesica Elsea, 1953 is considered a synonym of L. lasiura. New hosts of Longibucca lasiura include Pipistrellus subflavus, Lasionycteris noctivagans, and Myotis ciliolabrum. New geographic ranges of Longibucca lasiura are Virginia, U.S.A., Canada, and western North America.