Bail Nicola J, Lumsden Lindy F, Reardon Terry, van Harten Emmi, Clissold Paul, Prowse Thomas A A
School of Biological Sciences The University of Adelaide Adelaide South Australia Australia.
Department of Energy, Environment and Climate Action Arthur Rylah Institute for Environmental Research Heidelberg Victoria Australia.
Ecol Evol. 2025 May 4;15(5):e71281. doi: 10.1002/ece3.71281. eCollection 2025 May.
The time that bats emerge and subsequently return from a colonial roost determines their maximum foraging period and influences their exposure to mortality risks. The order in which different age and sex cohorts emerge and return reflects variation in these cohorts' resource requirements. The critically endangered Southern Bent-wing Bat () is an Australian insectivorous cave-roosting colonial bat. Resource limitation is hypothesised to have contributed to its decline but may not affect all cohorts equally. We tagged and monitored 3462 wild Southern Bent-wing Bats over 7 years with Passive Integrated Transponder technology. To infer resource requirements of different cohorts over the reproductive cycle, we estimated cohort-specific peak emergence and return times and the frequency of nocturnal returns to the roost. The emergence and return behaviour varied with age, sex, and throughout the annual reproductive cycle. Although adult females and males behaved similarly during the non-breeding period (winter), females emerged significantly (12-21 min) earlier and returned (27-62 min) later than males during pregnancy, lactation and weaning. Adult females were less likely than males to be detected overnight in the maternity roost while dependent young were present, suggesting that females prioritised maximising foraging over nocturnal nursing. When juveniles commenced flying, they delayed emergence until several hours after sunset (well after adults had departed the roost). During the 40-day weaning period, they progressively emerged earlier, such that by the end of this period they emerged with the adults, then subsequently foraged for longer than adults over winter. Passive monitoring of emergence and return behaviour in colonial bats can provide valuable data to infer cohort-specific resource requirements. Regular monitoring of a population's emergence and return times potentially allows for the early detection of changes in a resource requirements, and the use of PIT technology allows for the most vulnerable cohort(s) to be identified.
蝙蝠从聚居栖息地出现并随后返回的时间决定了它们的最大觅食期，并影响它们面临死亡风险的程度。不同年龄和性别的群体出现和返回的顺序反映了这些群体在资源需求上的差异。极度濒危的南弯翅蝠（）是一种澳大利亚食虫的洞穴栖息群居蝙蝠。据推测，资源限制是其数量下降的原因之一，但可能并非对所有群体都产生同等影响。我们在7年时间里使用被动集成应答器技术对3462只野生南弯翅蝠进行了标记和监测。为了推断不同群体在繁殖周期中的资源需求，我们估计了特定群体的高峰出现和返回时间以及夜间返回栖息地的频率。出现和返回行为随年龄、性别以及全年繁殖周期而变化。虽然成年雌性和雄性在非繁殖期（冬季）行为相似，但在怀孕、哺乳和断奶期间，雌性出现的时间明显更早（提前12 - 21分钟），返回的时间更晚（晚27 - 62分钟）。在育幼栖息地有依赖的幼崽时，成年雌性在夜间被检测到的可能性低于雄性，这表明雌性优先考虑最大化觅食而非夜间哺乳。当幼崽开始飞行时，它们会推迟出现，直到日落后数小时（远远晚于成年蝙蝠离开栖息地）。在40天的断奶期内，它们出现的时间逐渐提前，到这个时期结束时，它们与成年蝙蝠同时出现，然后在冬季觅食的时间比成年蝙蝠更长。对群居蝙蝠的出现和返回行为进行被动监测可以提供有价值的数据，以推断特定群体的资源需求。定期监测种群的出现和返回时间有可能早期发现资源需求的变化，而使用被动集成应答器技术可以识别出最脆弱的群体。
