The Relationships between Behavioural Categories and Social Influences in the Gregarious Big Brown Bat (Eptesicus fuscus)

Abstract

Behavioural plasticity is a critical component of natural selection leading to evolution. However, a surge of studies in the last two decades has discovered a distinct limit to behavioural plasticity, commonly referred to as behaviour types and behavioural syndromes. We set out to understand the relationships across behavioural categories in wild‐caught adult, female big brown bats and how they compare between social and solitary behaviours. Using bats sampled from four different maternity colonies, we ran a series of behavioural assays to create a behavioural profile for each individual. The behavioural profile encompassed exploratory, learning, competitive and aggressive categories. We found that Big brown bats exhibit a mean profile relatively unique to other well‐documented species, where aggression was linked to increased competitive ability but not to boldness. Our results indicate that the solitary and socially directed behaviours of individuals are not necessarily related and that behaviours pertaining to social interactions are linked most closely to learning abilities. Furthermore, we found evidence that poor body condition may be a predictor of increased social interactions and that behaviours exhibited in the presence of conspecifics are unrelated to those exhibited in solitude. These findings indicate importance of social affiliations on individual behaviours in this species and their uniqueness relative to other well‐studied taxa.

Morphological Correlates of Personality in Female Asian Particolored Bats (Vespertilio sinensis)

“…The Spix's disc-winged bat (Thyroptera tricolor) within social groups exhibits consistent individual differences in vocal behavior [38,39]. The isolated behaviors of big brown bats (Eptesicus fuscus) are not necessarily correlated with socially oriented behaviors [40][41][42]. These previous studies confirmed that bats have distinct personality traits, but the relationships between personality and body size remain unclear.…”

“…It is common to measure aggression in terms of frequency or proportion. For example, in studies of big brown bats (E. fuscus), the frequency of biting was used as a measure of aggression [40]. The aggressiveness of Wildtype Groningen rats (Rattus norvegicus) was measured by the proportion of the time spent on aggression to the total experimental time [30].…”

“…The intensity of behavioral relevance and the frequency of occurrence of different behavioral types, however, may vary between populations [89,90] and among social contexts [26,[91][92][93]. For example, the solitary and socially directed behaviors of individual big brown bats (E. fuscus) are not necessarily relevant [40]. In this study, we tested aggression when Asian particolored bats competed with conspecifics for roosting space, but we measured activity and exploration in isolated bats.…”

Host behaviour, age and sex correlate with ectoparasite prevalence and intensity in a colonial mammal, the little brown bat

“…Parasite risk is thought to be a major cost of social behaviour (Alexander, 1974;Altizer et al, 2003) and sociability is a trait with potentially important implications for parasite transmission. Despite the relatively solitary nature of adult male bats, they are still more gregarious than many other mammalian species (Thomas et al, 1979) and we recommend that future studies quantify individual differences in sociability among demographics and individual bats to assess its importance for transmission (e.g., Kilgour & Brigham, 2013).…”

Evidence of social preferences in big brown bats (Eptesicus fuscus)

“…Our knowledge of fission-fusion in bat societies suggests that preferential relationships are complex and may be explained by motivations other than simple kinship (Gillam et al 2011;Metheny et al 2008;Patriquin et al 2010;Kilgour and Brigham 2013). For example, females big brown bats are highly philopatric and live in colonies with overlapping matrilines (Vonhof et al 2008).…”