SUBSTRATE VIBRATION SENSITIVITY OF THE LEG SCOLOPIDIAL ORGANS IN THE GREEN-LACEWING, CHRYSOPERLA-CARNEA

The threshold sensitivity of the leg-vibration receptors of the green lacewing, Chrysoperla carnea, was investigated electro-physiologically . The legs were stimulated by sinusoidal vibrations. Summed responses from the leg nerve fibres of different legs do not differ much, In eac h leg there are two scolopidial organs which respond to vibration. The most sensitive-the subgenual organ-shows maximum sensitivity in the f requency range 1.5-2 kHz and a displacement threshold near 0.2 nm, cor responding to an acceleration of about 0.03 ms(-2), The other is the f emoral chordotonal organ with maximum sensitivity at about 1 kHz and t he threshold between 0.1 and 1 ms(-2). After ablation of both scolopid ial organs, only responses of non-scolopidial organs persist, very pro bably campaniform sensilla. (C) 1997 Elsevier Science Ltd.