The Effects of Microclimate Variations on the Behavior of a Maternity Colony of Eptesicus Fuscus, the Big Brown Bat PDF Download

Author: David Schwan
Publisher:
ISBN:
Category :
Languages : en
Pages : 40

View

Book Description

Author: Christopher Seth Richardson
Publisher:
ISBN:
Category :
Languages : en
Pages : 530

View

Book Description
Abstract: I examined regulatory nonshivering thermogenesis (NST), basal metabolic rate (BMR), and plasma levels of thyroid hormone (T3), leptin and cortisol in the big brown bat, Eptesicus fuscus, at seven maternity colonies in Massachusetts (MA) (northern population) and two maternity colonies in Alabama (AL)/Georgia (GA) (southern population) in 1997 and 1998 to test the hypothesis that these traits vary geographically. After accounting for effects of body mass and stage of pregnancy and within-population variation, I found that bats from the northern population did not differ significantly from those in the southern population for NST, BMR, T3, leptin and cortisol. For all traits, except for cortisol, the test for differences among all colonies from both populations was significant. For NST, colonies did not differ significantly within MA, whereas bats from the AL colony tended to have greater NST than all other colonies of bats examined. For BMR, colonies differed significantly within MA, whereas bats from the AL colony had significantly greater BMR than those from the GA colony. Moreover, the AL colony tended to have greater BMR than all other colonies of bats examined. For T3, leptin and cortisol, colonies did not differ significantly within MA, whereas bats from the AL colony had significantly greater T3, lower leptin and lower cortisol than those in the GA colony. Additionally, bats from the AL colony tended to have greater T3, lower leptin and lower cortisol than all other colonies. Thus, for NST, BMR, T3, leptin and cortisol, most or all of the variation among colonies cannot be explained by differences between populations (i.e., macro-geographic variation). Clearly, the absence of any predicted population differences along a clinal (adaptive) direction rules out evolutionary adaptations of bats to different thermal environments as the primary reason for differences among colonies for NST, BMR and their hormone correlates. However, the clear presence of among-colony, and within-population variation (i.e., micro-geographic) for these traits, suggests that environmental factors (acting recently) may play an important role in shaping the observed intra-specific variation in NST and BMR. Additionally, inter-individual variation and seasonal and sex differences were found for NST, BMR and the hormones.

Author: Kristin Jean Bondo
Publisher:
ISBN:
Category : Bats
Languages : en
Pages : 180

View

Book Description
Although microclimate inside the roost and amount of solar radiation received have been speculated to be factors driving roost switching behavior and roost tree selection by many species of forest-dwelling bats, precisely how or if solar radiation influences tree cavity temperature at the roost and landscape levels is unknown. I evaluated whether a maternity colony of Eptesicus fuscus in Cypress Hills, SK chose to roost in the warmest trees with the highest amounts of solar radiation. I measured solar radiation and temperature simultaneously at cavities in trembling aspen trees used by bats, as well as cavities available to bats but not used. To determine if tree cavity temperature could be predicted by its location on the landscape level, I compared temperatures inside tree cavities based on aspect values generated using GIS. Mean, maximum, minimum temperature and mean rate of change inside used and available roosts did not differ significantly. Total solar radiation and solar radiation reaching the cavity entrance did not differ significantly between used and available roosts. Roost cavities did not differ in mean temperature as a function of the aspect of the terrain. Ambient temperature was strongly correlated with roost temperature between 0700 and 1600 (R2 = 0.98, t = 19.0, p = 0.000). This supports the contention that roost tree temperature inside cavities varies little and is principally determined by ambient temperature. Bats did not select or switch roost trees based on differences in temperature, but most likely select roost trees with large cavity volumes that can hold many individuals, so they can socially thermoregulate, and most likely switch roosts to avoid build up of ectoparasites, guano, and/or to facilitate knowledge and information transfer among potential roost trees.

Author: Jackie Dawn Metheny
Publisher:
ISBN:
Category : Bats
Languages : en
Pages :

View

Book Description
"In Cypress Hills Interprovincial Park, Saskatchewan, Canada, tree-roosting big brown bats (Eptesicus fuscus) exhibit fission-fusion roosting behavior and are philopatric to one of three non-overlapping roosting areas. Bats switch roost trees and potentially roost-mates about every two days, and bats appear to have preferred roost-mates. To assess whether genetic relationships mediate fission-fusion behavior in tree-roosting bats, I combined genetic analyses (microsatellite loci and mitochondrial DNA) with behavioral studies. First, I determined whether female philopatry produced genetic subdivision among the roosting areas. Second, I examined roosting associations within one roosting area to determine whether roost-mate decisions were based on genetic relationships. I found that female-mediated gene flow was restricted between roosting areas while male-mediated gene flow was not. Roosting associations were not influenced by genetic relationships. Mating and dispersal behavior of E. fuscus generate group members that are generally not closely related, and bats do not preferentially roost with closely related or matrilineal females. Thus, kin selection is an unlikely explanation for preferred roost-mates, group stability, and cooperation in tree-roosting E. fuscus."--Abstract from author supplied metadata.

Author: Michael J. Lacki
Publisher: JHU Press
ISBN: 0801884993
Category : Nature
Languages : en
Pages : 350

View

Book Description
Although bats are often thought of as cave dwellers, many species depend on forests for all or part of the year. Of the 45 species of bats in North America, more than half depend on forests, using the bark of trees, tree cavities, or canopy foliage as roosting sites. Over the past two decades it has become increasingly clear that bat conservation and management are strongly linked to the health of forests within their range. Initially driven by concern for endangered species—the Indiana bat, for example—forest ecologists, timber managers, government agencies, and conservation organizations have been altering management plans and silvicultural practices to better accommodate bat species. Bats in Forests presents the work of a variety of experts who address many aspects of the ecology and conservation of bats. The chapter authors describe bat behavior, including the selection of roosts, foraging patterns, and seasonal migration as they relate to forests. They also discuss forest management and its influence on bat habitat. Both public lands and privately owned forests are considered, as well as techniques for monitoring bat populations and activity. The important role bats play in the ecology of forests—from control of insects to nutrient recycling—is revealed by a number of authors. Bat ecologists, bat conservationists, forest ecologists, and forest managers will find in this book an indispensable synthesis of the topics that concern them.

Author: James A. Howard
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description

Author: Michael Scott Kranbuhl
Publisher:
ISBN:
Category : Bats
Languages : en
Pages : 90

View

Book Description

Author: Christopher Drake Burnett
Publisher:
ISBN:
Category : Bats
Languages : en
Pages : 183

View

Book Description

Author: Gabrielle F. Diamond
Publisher:
ISBN:
Category : Bat-compatible mine gates
Languages : en
Pages : 122

View

Book Description
With the loss or modification of natural roosting habitat afforded by caves, abandoned mines have assumed increased importance as surrogate roosting sites for Townsend's big-eared bats (Corynorhinus townsendii) and other chiropteran species. However, increasing concerns for human safety have led to accelerated programs for mine closure. In efforts to protect roosting sites in mines showing significant bat activity, "bat compatible" gates are installed, thus allowing continued access to mine workings. Aside from ensuring public safety, these structures afford protection from disturbance to roosting bats. To date few posting-gating studies have been conducted to obtain information on the effects of these structures on bat behavior and roost suitability. I evaluated the effects of gating on bat flight patterns at maternity colonies in two previously gated (reference) and two ungated mines, the latter (treatment) being gated with roundbar Manganal steel gates in the second year of the study. I also monitored four gated and three treatment mines to determine the potential effects of reclamation on internal microclimate. Overall circling activity increased > 6-fold at the portals of treatment mines following gating. Indices of crowding and frequency of bat-gate collisions were significantly higher in previously gated and increased substantially in treatment mines following reclamation. Gates appeared especially hazardous to subadults during initial-volancy periods. Increased activity of bats and collisions with gates at mine portals may amplify vulnerability to potential predators. Changes in internal mine microclimates, specifically increased ranges between minima and maxima in temperature and vapor pressure deficits following reclamation varied among treatment mines as a function of the number of mine openings. Generally, gated mines with multiple openings experienced greater changes in these parameters than those with single openings. Additional studies of bat-compatible gates are needed to elucidate possible long-term effects of these structures on Townsend's big-eared bats.

Author: Molly C. Simonis
Publisher:
ISBN:
Category : Biology
Languages : en
Pages : 0

View

Book Description
Disturbances in environment can lead to a wide range of host physiological responses. These responses can either allow hosts to adjust to new conditions in their environment or can reduce their survival, and can subsequently cause host traits to shift. Small mammals are particularly vulnerable to stochastic disturbances, like a pathogen introduction, because of their high energy demands. Studies examining host responses to pathogens often focus on species highly susceptible to infection that typically have high mortality rates, leading to a gap in understanding the responses of less susceptible species. My dissertation evaluates the energy balance of Eptesicus fuscus (big brown bats), a species considered less susceptible to the introduced fungal pathogen Pseudogymnoascus destructans (Pd) which causes white-nose syndrome in North American hibernating bats. I quantified changes in body mass, energy expenditures and the abundance of E. fuscus over long-term Pd exposure time. Using 30 years of data for 24,129 individual E. fuscus captures across the eastern US, I found E. fuscus body mass decreased with increasing latitude once Pd was established on the landscape (5+ years). When measuring whole-animal energy expenditures of 19 E. fuscus in lab settings using open-flow respirometry, I found that E. fuscus with long-term exposure to Pd have increases or no change to torpid metabolic rates across a wide range of ambient temperatures. Finally, the overall abundance of E. fuscus increased with Pd exposure, and lactating and post-lactating bats increased abundance with increasing latitude in the eastern US. Taken together, these results suggest that E. fuscus may have a combination of pathogen and intraspecific competitive pressures impacting their populations, particularly in northern latitudes. This dissertation highlights how introduced pathogens can cause spatially variable responses in less susceptible hosts over time, and other ecological pressures may contribute to those responses. Future efforts for understanding the degree of persistence of less susceptible wildlife host populations are critical for predicting how and why their populations change following emerging infectious disease outbreaks and epidemics.