Calling louder and longer: how bats use biosonar under severe acoustic interference from other bats

Active-sensing systems such as echolocation provide animals with distinct advantages in dark environments. For social animals, however, like many bat species, active sensing can present problems as well: when many individuals emit bio-sonar calls simultaneously, detecting and recognizing the faint echoes generated by one's own calls amid the general cacophony of the group becomes challenging. This problem is often termed ‘jamming’ and bats have been hypothesized to solve it by shifting the spectral content of their calls to decrease the overlap with the jamming signals. We tested bats’ response in situations of extreme interference, mimicking a high density of bats. We played-back bat echolocation calls from multiple speakers, to jam flying Pipistrellus kuhlii bats, simulating a naturally occurring situation of many bats flying in proximity. We examined behavioural and echolocation parameters during search phase and target approach. Under severe interference, bats emitted calls of highe...诸如回声定位（echolocation）这类主动感知系统，可帮助动物在黑暗环境中获得显著优势。然而对于多数蝙蝠物种这类社会性动物而言，主动感知同样会引发难题：当大量个体同时发射生物声纳呼叫时，在群体的嘈杂声响中，检测并识别自身呼叫产生的微弱回声将极具挑战。这类问题通常被称为“干扰（jamming）”，已有假说提出，蝙蝠可通过调整自身呼叫的频谱成分，降低与干扰信号的重叠度来解决该问题。我们在模拟高密度蝙蝠群体的极端干扰场景下，测试了蝙蝠的应对反应。我们通过多台扬声器播放蝙蝠回声定位呼叫，对飞行中的库氏伏翼（Pipistrellus kuhlii）进行干扰，模拟了多只蝙蝠近距离飞行的自然场景。我们分析了蝙蝠在搜索阶段与目标趋近阶段的行为及回声定位参数。在严重干扰条件下，蝙蝠发出的呼叫的[原文此处截断为“highe...”]