Auditory-guided behaviour at two extremes of sensory processing

• Applicant: Dr. Holger R. Goerlitz
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: from 2013 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 241711556

Predator-prey interactions are key to the survival of most animals: predators need to eat, while prey need to survive. This reciprocal dynamic lead to the diffuse co-evolution of various adaptations for optimized attack and escape. Besides structural, morphological and anatomical adaptations, like armour or muscle mass, sensorial and behavioural strategies are a key component for both predators and prey. Both need to detect and localise each other to elicit behavioural responses, and both employ sensory strategies to prevent detection, such as camouflage. While visual sensory strategies that mediate the coexistence of predators and prey are well studied, this is not the case for sensory strategies in the auditory domain, which I will investigate here.Predators, like any animal, constantly experience an overload of environmental information, of which only a small part is behaviourally relevant and which needs to be filtered and selected by appropriate sensori-cognitive processes. In the predator subproject, I will investigate the prey detection and selection strategies of the barbastelle bat. Based on my previous observations, I hypothesize that this specialized hunter exploits multiple sensory cues to detect fluttering insects, including prey-generated sounds and time-variant echo-patterns generated by the prey’s wingbeat. I will characterize those sensory cues and will test their perception as a novel sensory strategy of a bat that emits calls with short duration. Integrating multiple sensory cues would make prey information perceptually more salient and better detectable within the overload of environmental information.Prey species that communicate with highly conspicuous song seem to be maladapted to the predation threat by eavesdropping predators. The prey subproject will extend my model systems to include the singing bushcricket Ruspolia nitidula, which emits a highly conspicuous and continuous song, is not chemically defended and does not stop singing in response to simulated bat calls, and yet is not consumed by bats. I thus propose that continuously singing species rely on other defence strategies to prevent predation. I will test the hypothesis that singing continuously in groups offers protection from predation because the mammalian auditory system cannot localize individual sound sources in this situation. Secondly, I will test the hypothesis that the song interferes (“jams”) with bat echolocation, in this way even protecting other insects close-by flying from bat predation via short-term acoustic commensalism.

• DFG Programme: Independent Junior Research Groups