Extrinsic and intrinsic factors influencing the emergence and return of the Asian particolored batVespertilio sinensisto the summer roost

Abstract

Circadian rhythms play a crucial role in the health and survival of organisms. However, little is known concerning how intrinsic and extrinsic factors affect animal daily rhythms in the field, especially in nocturnal animals. Here, we investigated the first emergence, mid‐emergence, and return times of Vespertilio sinensis , and also integrated environmental conditions (temperature, humidity, and light intensity) and biotic factors (reproductive status and predation risk) to determine causes of variation in the activity rhythms of the bats. We found that variation in the first emergence time, the mid‐emergence time, and the final return time were distinct. The results demonstrated that the emergence and return times of bats were affected by light intensity, reproductive status, and predation risk in a relatively complex pattern. Light intensity had the greatest contribution to activity rhythms. Moreover, we first investigated the effects of actual predators on the activity rhythms of bats; the results showed that the mid‐emergence time of bats was earlier as predators were hunting, but the final return time was later when predators were present. Finally, our results also highlighted the importance of higher energy demands during the lactation in bats to variation in activity rhythms. These results improve our understanding of the patterns and causes of variation in activity rhythms in bats and other nocturnal animals.

Wildlife Use of Anthropogenic Structures: A Comprehensive Review of Bridge Use by Bats

“…One primary structural characteristic all bridge designs share is the availability of suitable spaces for bats to take shelter. As mentioned previously, roost selection is often driven by the availability of structural characteristics such as cracks, crevices, and gaps, which can be found in expansion joints, alcoves, abutments, and between girders (Davis and Cockrum, 1963; Hirshfeld et al ., 1977; Pierson et al ., 1996; Keeley and Tuttle, 1999; Feldhamer et al ., 2003; Keeley and Keeley, 2004; Ceľuch and Ševčík, 2008; Geluso and Mink, 2009; Allen et al ., 2011; Cervone and Yeager, 2016; Bachen and McEwan, 2019; Etchison and Weber, 2020; Feng et al ., 2022). These suitable spaces tend to be crevices that span parallel and perpendicular to a bridge deck and are often just wide enough for bats to fit inside.…”

“…1A and 1C). Various studies in the eastern and south-eastern regions of North America (Trousdale and Beckett, 2004; Ferrara and Leberg, 2005; Bennett et al ., 2008; Borges-Jesús et al ., 2021), Europe (England, France, Bulgaria, Portugal, Slovakia, Spain, Scotland, and Ireland — Speakman et al ., 1991; Jones et al ., 1996; McGuire, 1998; Flavin et al ., 2001; Keeley, 2007; Tilova et al ., 2008; Mendes et al ., 2011; Papadatou et al ., 2011; Amorim et al ., 2013; Kaňuch et al ., 2016; Barré et al ., 2021), Asia (Takumi et al ., 2007; Chung et al ., 2009; Feng et al ., 2022), South America (Díaz and Linares García, 2012; Benvindo-Souza et al ., 2021), Africa (Ahmim, 2017; Czenze et al ., 2022), and Pacific Islands (Dwyer, 1960; Daniel and Williams, 1984) have documented bridge use, with more than half of North American bat species and 68% of European species documented roosting in bridges (Amorim et al ., 2013; Sparks et al ., 2019; Fig. 1B and 1C).…”

Feeding behavior innovation increases foraging efficiency in the Amur falcon but may be a threat to Asian particolored bats

“…Our previous study found that more than 65% of the first emergence events of V . sinensis occurred before sunset during lactation, whereas only about 7% of the first emergence events occurred before sunset during post‐lactation (Feng et al, 2022 ). The energetic cost of an adult female bat is increased considerably, peaking during lactation (Kunz, 1987 ).…”

“…Here, V. sinensis often emerged from the roost before sunset during the lactation period (in July), which was earlier than during the post-lactation period (after July). Our previous study found that more than 65% of the first emergence events of V. sinensis occurred before sunset during lactation, whereas only about 7% of the first emergence events occurred before sunset during post-lactation (Feng et al, 2022). The energetic cost of an adult female bat is increased considerably, peaking during lactation (Kunz, 1987).…”

Artificial light affects foraging behavior of a synanthropic bat

“…Adult females form maternal colonies between May and August comprising several tens to thousands of members (Fukui & Agetsuma 2010;Luo et al 2017). Most V. sinensis emerge to forage within 30 min of sunset according to the ambient illumination level, reproductive status, and level of predation risk (Feng et al 2022). To achieve our goal, we monitored foraging behavior, freezing time, and echolocation vocalizations of female V. sinensis under six controlled lighting conditions in the laboratory, including dark control (DC), white light (WL), blue light (BL), green light (GL), yellow light (YL), and red light (RL).…”