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

Abstract

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.

Assessing survival in a multi-population system: a case study on bat populations

“…Second, to investigate variation in survival on a fine scale, we estimated the survival probability of each colony separately and compared estimates between pairs of colonies. Differences in survival among colonies may be related to a variety of colony-specific factors, such as quality of foraging and roosting habitat, density-dependent processes, human disturbance, road kills (Russell et al 2009), age structure and senescence effects (Festa-Bianchet et al 2003) and immunological response to disease (Allen et al 2009). To estimate survival probabilities at each different habitat type or colony we treated temporal variation as a random effect e t following a normal distribution with mean 0 and variance r 2 .…”

Inflammatory challenge increases measures of oxidative stress in a free-ranging, long-lived mammal

“…Although it is crucial to understand how the immune system of bats works and how they defend themselves against these pathogens, surprisingly little is known about bat immunity and the factors influencing it (Dobson, 2005). Recent studies have shown a correlation between immune parameters and ecological factors such as dietary niche and roost use in bats (Allen et al, 2009;Schneeberger et al, 2013). Also, experiments on Mexican free-tailed bats (Tadarida brasiliensis) demonstrated that they can mount a considerable cellular immune response after injection of mitogens such as phytohaemagglutinin (Allen et al, 2009).…”

“…Recent studies have shown a correlation between immune parameters and ecological factors such as dietary niche and roost use in bats (Allen et al, 2009;Schneeberger et al, 2013). Also, experiments on Mexican free-tailed bats (Tadarida brasiliensis) demonstrated that they can mount a considerable cellular immune response after injection of mitogens such as phytohaemagglutinin (Allen et al, 2009). As in most other animals, variations in immune responses can be linked to disease susceptibility, such as the white-nose syndrome in temperate-zone bats that eradicated millions of bats in North America during the last decade (Lorch et al, 2011;Moore, 2011).…”

Innate Immunity in Free-Ranging African Buffalo (Syncerus caffer): Associations with Parasite Infection and White Blood Cell Counts

“…Empirical studies in ecoimmunology have focused largely on birds (e.g., see AlonsoAlvarez and Tella 2001;Grasman 2002;Friedl and Edler 2005;Lee et al 2008;Wilcoxen et al 2010) and invertebrates (e.g., Moret and Schmid-Hempel 2001;Moret and Siva-Jothy 2003;Cremer and Sixt 2009), extending strong foundations in lifehistory theory in these taxa. Transferring these approaches to free-living mammal species has only recently begun (see, e.g., Allen et al 2009;Ezenwa et al 2011b;Graham et al 2011;Jackson et al 2011).…”