Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA
Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD 21218, USA.
J Exp Biol. 2018 Aug 13;221(Pt 15):jeb176511. doi: 10.1242/jeb.176511.
Echolocating bats often forage in the presence of both conspecific and heterospecific individuals, which have the potential to produce acoustic interference. Recent studies have shown that at least one bat species, the Brazilian free-tailed bat (), produces specialized social signals that disrupt the sonar of conspecific competitors. We herein discuss the differences between passive and active jamming signals and test whether heterospecific jamming occurs in species overlapping spatiotemporally, as well as whether such interference elicits a jamming avoidance response. We compare the capture rates of tethered moths and the echolocation parameters of big brown bats () challenged with the playback of the jamming signal normally produced by Brazilian free-tailed bats and playback of deconstructed versions of this signal. There were no differences in the capture rates of targets with and without the jamming signal, although significant changes in both spectral and temporal features of the bats' echolocation were observed. These changes are consistent with improvements of the signal-to-noise ratio in the presence of acoustic interference. Accordingly, we propose to expand the traditional definition of the jamming avoidance response, stating that echolocation changes in response to interference should decrease similarity between the two signals, to include any change that increases the ability to separate returning echoes from active jamming stimuli originating from conspecific and heterospecific organisms. Flexibility in echolocation is an important characteristic for overcoming various forms of acoustic interference and may serve a purpose in interspecific interactions as well as intraspecific ones.
回声定位蝙蝠通常在同种和异种个体同时存在的情况下觅食，这些个体有可能产生声学干扰。最近的研究表明，至少有一种蝙蝠物种，即巴西无尾蝙蝠（），会产生专门的社交信号，扰乱同种竞争者的声纳。我们在此讨论被动和主动干扰信号之间的差异，并测试同种重叠时空的物种是否会发生异源干扰，以及这种干扰是否会引发干扰回避反应。我们比较了被拴住的飞蛾的捕获率和大褐蝙蝠的回声定位参数，这些蝙蝠受到巴西无尾蝙蝠正常产生的干扰信号的回放和这种信号的分解版本的回放的挑战。有和没有干扰信号的目标的捕获率没有差异，尽管蝙蝠回声定位的光谱和时间特征都发生了显著变化。这些变化与在存在声干扰时信号噪声比的提高一致。因此，我们建议扩展干扰回避反应的传统定义，指出为了应对干扰而改变的回声定位应该降低两个信号之间的相似性，包括任何能够提高从同种和异种生物发出的主动干扰刺激中分离回波的能力的变化。回声定位的灵活性是克服各种形式的声学干扰的重要特征，它可能在种间和种内相互作用中都有作用。
