Louise C. Allen

Roosting ecology and variation in adaptive and innate immune system function in the Brazilian free-tailed bat (Tadarida brasiliensis)

Bats have recently been implicated as reservoirs of important emerging diseases. However, few studies have examined immune responses in bats, and even fewer have evaluated these responses in an ecological context. We examined aspects of both innate and adaptive immune response in adult female Brazilian free-tailed bats (Tadarida brasiliensis) at four maternity roosts (two natural caves and two human-made bridges) in south-central Texas. Immune measurements included in vitro bactericidal ability of whole blood and in vivo T cell mediated response to mitogenic challenge. Bactericidal activity in T. brasiliensis varied with roosting ecology, but appears to be sensitive to colony-level effects. Blood from females living at one cave had significantly lower bactericidal ability than blood from females at three other sites. T cell mediated response in this species was associated with variation in roost ecology, with females from two caves having greater responses than females from two bridges. T cell mediated response and bactericidal activity were negatively correlated with one another within individuals that were tested for both. Variation in immunological response of T. brasiliensis is important for understanding the influence of the environment on the frequency and distribution of immunologically competent individuals and for understanding disease-host dynamics in this and other colonial species.

Ecology of Rabies Virus Exposure in Colonies of Brazilian Free-Tailed Bats (Tadarida brasiliensis) at Natural and Man-Made Roosts in Texas

Previous studies have investigated rabies virus (RABV) epizootiology in Brazilian free-tailed bats (Tadarida brasiliensis) in natural cave roosts. However, little is known about geographic variation in RABV exposure, or if the use of man-made roosts by this species affects enzootic RABV infection dynamics within colonies. We sampled rabies viral neutralizing antibodies in bats at three bridge and three cave roosts at multiple time points during the reproductive season to investigate temporal and roost variation in RABV exposure. We report seropositive bats in all age and sex classes with minimal geographic variation in RABV seroprevalence among Brazilian free-tailed bat colonies in south-central Texas. While roost type was not a significant predictor of RABV seroprevalence, it was significantly associated with seasonal fluctuations, suggesting patterns of exposure that differ between roosts. Temporal patterns suggest increased RABV seroprevalence after parturition in cave colonies, potentially related to an influx of susceptible young, in contrast to more uniform seroprevalence in bridge colonies. This study highlights the importance of life history and roost ecology in understanding patterns of RABV seroprevalence in colonies of the Brazilian free-tailed bat.

Evening Emergence Behavior and Seasonal Dynamics in Large Colonies of Brazilian Free-Tailed Bats

Abstract Flexible behaviors permit gregarious animals to exploit spatially and temporally favorable conditions for reproduction. Evening emergences of Brazilian free-tailed bats (Tadarida brasiliensis) in south-central Texas were recorded to determine changes in colony dynamics and to evaluate hypotheses associated with predator avoidance and seasonal energy demands. In 2007, median parturition date was 18 June and lactation lasted about 54 days. Juveniles commenced flight after 41 days, then continued to suckle for 2 weeks before being weaned. Onset of evening emergence was correlated with sunset, beginning, on average, 11.8 min after sunset (95% confidence interval  =  7.1, 16.6), which is later than reported in previous studies. Pregnant females emerged later than their roost mates, consistent with a predator avoidance hypothesis. Lactating females emerged after sunset, but earlier than other bats, consistent with the hypothesis that this is a period of high energy demand. Juveniles emerged later than adult females while they continued to be suckled, but emerged earlier as they matured and were weaned, suggesting a trade-off between predator avoidance and energy demands. Our observations indicate that evening emergence behavior of T. brasiliensis varies with environmental cues but is mediated by the energetic demands of reproduction.

Variation in physiological stress between bridge- and cave-roosting Brazilian free-tailed bats.

Since the late 1980s, Brazilian free-tailed bats (Tadarida brasiliensis) have increasingly used bridges as roosts in the southern United States. We examined differences in blood cortisol levels, body condition, and parasite load, as measures of physiological stress in bats roosting in bridges and bats roosting in caves. We collected data during three periods, coinciding with female phases of reproduction. For all measures, bats were captured during the nightly emergence from the roost and immediately sampled. Cortisol levels were significantly higher during pregnancy and lactation and in individuals with lower body-condition scores (length of forearm to mass ratio) and significantly higher in bats roosting in caves than in those roosting in bridges. Thus, we concluded that individuals of this species that roost in bridges are not chronically stressed and seem to be unaffected by human activities present at bridges. This is a rare documented instance where a human-dominated environment does not appear to be adversely affecting the physiological health of a free-ranging animal.

New Advances in the Study of Group Behavior in Bats

The collective behavior of organisms results in spectacular displays that have inspired scientific inquiry for centuries. Recently, rich theoretical work has complemented traditional biological observation to offer fresh insights into the function and mechanisms of animal groups. Although these theoretical studies unquestionably have advanced our understanding of the dynamics of animal groups, further progress will depend on the ability to reconcile numerical methods with empirical data from realistic, field-based studies of existing, as well as new, animal models. Fortunately, the technical challenges associated with collecting such data from large, free-ranging groups are becoming less daunting as a new generation of field-portable technologies becomes increasingly available. By combining novel analytical approaches and better integration of different data modalities, it is now possible to produce stunningly informative representations of the behavior of animal groups. Although the group dynamics of bats are as intriguing and potentially informative as those of other animal groups, until now the difficulty of access has inhibited studying how bats structure and maintain their groups. Here we present some of the first data from large colonies of free-ranging bats. Our initial investigations offer vivid glimpses into the group dynamics of these mammals and underscore the value and importance of this focus for further experimental research in the field. Such studies could not only reveal more about functional complexity in nature and further inform our understanding of animal groups but suggest principles by which we organize and might even improve our own society.

Response to Vaccination with a Commercial Inactivated Rabies Vaccine in a Captive Colony of Brazilian Free-Tailed Bats (Tadarida brasiliensis)

Abstract A captive colony of Brazilian free-tailed bats (Tadarida brasiliensis) was vaccinated with a commercial monovalent inactivated rabies virus (RABV) vaccine (RABVAC 1). Baseline rabies virus neutralizing antibodies (VNA) and the response to vaccination were measured in 50 bats. Rabies VNA was detected in the plasma of 64% (27/42) of bats that had been vaccinated 1 yr prior, but only 19% (8/42) had levels considered adequate. Rabies VNA was detected in the plasma of 63% (5/8) of bats with no record of previous vaccination, suggesting natural RABV exposure before captivity. All bats demonstrated a VNA response by 10 days postvaccination, and baseline titer significantly predicted humoral response to vaccination. No adverse reactions to vaccination or clinical signs of RABV infection were observed in the bats during a 6-mo observation period. Annual vaccination may maintain immunity against RABV infection in captive colonies of bats.

Science in the Public Eye: Leveraging Partnerships—An Introduction

With stories of struggle and dramatic breakthroughs, science has incredible potential to interest the public. However, as the rhetoric of outrage surrounds controversies over science policy there is an urgent need for credible, trusted voices that frame science issues in a way that resonates with a diverse public. A network of informal educators, park rangers, museum docents and designers, and zoo and aquarium interpreters are prepared to do so during millions of visits a year; just where science stories are most meaningfully told-in the places where members of the public are open to learning. Scientific researchers can benefit from partnerships with these intermediaries who are accorded status for their trustworthiness and good will, who have expertise in translating the science using language, metaphors, encounters, and experiences that are appropriate for non-experts. In this volume, we describe and probe examples wherein scientists work productively with informal educators and designers, artists, staff of federal agencies, citizen scientists, and volunteers who bring science into the public eye.

Beyond the Brown Bag: Designing Effective Professional Development for Informal Educators

Most researchers are keenly interested in disseminating their work beyond traditional publication routes. With an eye to increasing broader impacts, scientists can benefit from partnerships with informal educators who interact daily with the public and see their role as translating science to increase the publics intellectual and emotional connections with the natural world. Typically, researchers give a one-time lunch hour talk, generally a modified version of a presentation aimed at scientific peers. Talks during which scientists show slides and interpreters mainly listen are a missed opportunity. They leave the scientist no wiser about the publics interests and the nagging questions interpreters have. Such talks leave the conscientious park educator with insufficient resources for overcoming challenges in interpreting the science for the public. The Interpreters and Scientists Working on Our Parks (iSWOOP) project proposes a model of professional development (PD) that involves a deliberate partnership where scientists and educators work together. During site-based PD sessions, they tease out the relevance to public audiences and begin to develop programs about the science. This article describes iSWOOPs approach to supporting productive collaborations that promote an understanding of scientific research to public audiences. Results from a pair of surveys indicate that both sides of this partnership benefit from extended contact and clear communication.

VIA - Visualizing Individual Actions to Develop a Sustainable Community Culture through Cycling

Improving the sustainability of our society requires significant change in our collective behavior. But today, individuals in our society have no regular way of seeing that collective behavior, or how their own behavior compares to it. We are creating a research network that will study how new technologies such as mobiles and visualization can encourage individuals to change their behavior to improve sustainability. In Winston-Salem NC, network members will use new technologies to engage the community about its use of transportation--especially biking--and study how that communication affects sustainability awareness and behavior.