Diurnal behavior and activity budget of the golden-crowned flying fox (<i>Acerodon jubatus</i>) in the Subic bay forest reserve area, the Philippines

Abstract

Acerodon jubatus (the Golden-Crowned flying fox) is an endemic species in the Philippines, which was suspected to be a host of the Reston strain of the Ebola virus. As nocturnal animals, the flying foxes spend daytime at the roosting site, which they use for self-maintenance and reproduction. To understand the variation in diurnal behavior and time allocation for various activities in the Golden-Crowned flying fox, we investigated their daytime behavior and activity budget using instantaneous scan sampling and all occurrence focal sampling. Data collection was performed from 07:00 to 18:00 hr during January 8–17, 2017. The most frequent activity was sleeping (76.3%). The remaining activities were wing flapping (5.0%), self-grooming (4.2%), hanging relaxation (3.4%), wing spread (2.9%), movement (2.4%), mating/courtship (2.4%), aggression (1.9%), hanging alert (1.2%), excretion (0.1%) and scent marks (0.05%). The frequency of sleeping, wing flapping, self-grooming, hanging relaxation, aggression, mating/courtship and movement behaviors changed with the time of the day. Females allocated more time for resting than males, while males spent more time on the activities that helped enhance their mating opportunities, for example, movement, sexual activity and territorial behavior.

The behavioural costs of overcrowding for gregarious cave‐dwelling bats

“…Aggregated colonies exhibit a significantly higher incidence of wing‐flapping behaviour, which is also used to assert dominance within a group and may be more prevalent in densely populated aggregations with limited space (Beauchamp, 2007; Kerth, 2008). Furthermore, aggregated groups exhibited a higher frequency of individual movement than their non‐aggregated counterparts, possibly because they disturb each other and become hotter and therefore uncomfortable (Hengjan et al., 2017; Ramanantsalama et al., 2019).…”

“…Furthermore, the positive correlation between relaxation and thermoregulation behaviour indicates that bats in aggregated colonies may alternate between cooling down and resting (Becker et al., 2012; Komar et al., 2022). Additionally, the positive correlation between relaxation behaviour and self‐maintenance, as well as positive social behaviour, implies that bats in non‐aggregated colonies might use relaxation to recharge and engage in social interactions during their active hours, which could enhance their overall fitness and well‐being (Hengjan et al., 2017).…”

“…The behaviours recorded included sexual activity, self‐maintenance, thermoregulation, positive social behaviour, negative social behaviour, territorial behaviour and non‐categorised behaviour following Friard and Gamba (2016) and Hengjan et al. (2017) (Table 1). The two openings of the cave are vertical, and bats roosting in these areas are prone to predation, with some colonies moving in the inner part during heavy rains.…”

“…We exported and cleaned the data from BORIS and quantified the frequency (count) of incidents in each behavioural unit and category by tallying the number of times a specific behaviour occurred within the designated time frame of observation. Similarly, we determined the duration of each behavioural category and unit by calculating the ratio of the observed time ( t , s ) for each behavioural unit to the total observation period ( T , s ; Connell et al., 2006; Hengjan et al., 2017). In our final analysis, we only analysed the frequency of incidents because we found a strong correlation between the frequency and duration of behaviour.…”

“…Understanding how bats react to suboptimal conditions presents a major ecological challenge. Most investigations have centred on non‐cave bat species in their natural roosts or enclosures (García‐Rawlins et al., 2020; Hengjan et al., 2017; Thomson et al., 1998). Thus, little work has been done to explore these phenomena in cave bats, likely due to the difficulty and expense of studying bats in the wild (Reeder et al., 2004; Revilla‐Martín et al., 2021).…”