Auditory interactions in the night sky

  • Datum: 26.02.2015
  • Uhrzeit: 13:00 - 14:00
  • Vortragende(r): Dr. Holger Goerlitz, Research Group Leader "Acoustic and Functional Ecology"
  • Raum: Seewiesen, Seminar Room House 4, Videoconf. to Radolfzell, Tea & Coffee 12:30
The aim of this talk is to introduce the work of the Acoustic and Functional Ecology Group, where we investigate sensory and behavioural strategies of interacting predators and prey, and to present some of the past work conducted by the Sensory Ecology Group on species interactions. Auditory information is the main sensory modality of echolocating bats, making them an ideal model system to investigate the sensory mechanisms and evolutionary adaptations of auditory processing. Due to their high intensity, bat echolocation calls are susceptible to eavesdropping by other animals, such as their prey or con- and heterospecific bats. We investigated the interspecific interactions of bats in a combined lab- and field-experiment, particularly testing if bats listen to the echolocation calls of other bats and make use of this information for their own decision making. Listening out for bat calls is even more relevant for prey insects. The strong predator-mediated selection pressure lead to the independent evolution of ears in many insect taxa. To escape from bats, eared moths possess simple ears, consisting of only 1-4 neurons, and a two-staged evasive flight response. Despite this simplicity, we showed that these ears are adapted to the species-specific predation pressure posed by their sympatric bat community and that they enable just-in-time evasive flight across multiple bat species that differ in the amount of predation threat. In contrast, predators generally experience a lower selection pressure to counter prey defences. Thus, evidence for a coevolved bat counterstrategy to moth hearing had been ambiguous. The barbastelle bat, however, is able to prey almost exclusively on eared moths by emitting low-amplitude calls, which are inaudible to moths, costly for the bat, and are derived from a high-intensity ancestral state, suggesting they are an adaptation to moth hearing. Our current work uses eared moths and echolocating bats as model system to study auditory guided flight at two extremes of sensory processing, focusing on dynamic biosonar emission and perception, and on behavioural variability as anti-predator adaptation.
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