Visual landmark orientation by flying bats at a large-scale touch and walk screen for bats, birds and rodents.

Orientation depends on multi-modal information about the locally perceptible environment (local view) in many situations. We developed a behavioural paradigm for investigating visual orientation of flying bats based on a large-scale touch screen (1.2 m x 1.

Male recognition mechanism for female responses implies a dilemma for their localisation in a phaneropterine bushcricket.

The phonotactic behaviour of the duetting bushcricket Poecilimon ornatus was investigated on a walking compensator when two females responded to the male's call. Whenever two female clicks from different directions were presented within the time window, males tracked an intermediate course even when the two clicks were separated by up to 60 ms and differed widely in intensity. Thus, any signal arriving within that interval contributes to the localization of the female response.

AUDITORY THRESHOLD CHANGE IN SINGING CICADAS.

The hearing sensitivity in singing cicadas is reduced during sound production by a folding of the tympanal membranes. Using electrophysiological recording and nerve stimulation techniques, we have shown an effect of the folded tympanum on the auditory threshold of two species of cicadas, Tibicen linnei and Okanagana rimosa. Auditory thresholds of both species increased by about 20 dB when the tympana folded during singing.

FUNCTION OF THE TENSOR MUSCLE IN THE CICADA TIBICEN LINNEI.

The calling song and the disturbance squawk of the cicada Tibicen linnei (Insecta: Homoptera) are described in terms of their physical parameters. The calling song is composed of quiet parts, which are very similar to the disturbance squawk, and loud parts, which are amplitude- and rate-modulated. The role of the tensor muscle acting on the tymbal frame in modulating the sound pulse amplitude was investigated.