D.N.LAPSHIN, D.D. VORONTSOV
ACTIVATION OF ECHOLOCATION SIGNAL EMISSION BY NOCTUID MOTHS (NOCTUIDAE, LEPIDOPTERA) IN RESPONSE TO RETRANSLATION OF ECHO-LIKE STIMULI
Among invertebrates, only noctuid moths (Noctuidae, Lepidoptera) are known
to possess capability for echolocation. Their signals represent short
ultrasonic clicks which are generated during flight. Maximal distance
of echo detection is (by different estimations) from 10 to 30 cm
(Lapshin et al.,1993, Zool.jurn.; Lapshin, 1995, Sensorn.Syst.,Rus.).
The frequency of sound emission significantly affects the efficacy
of echolocation at small distances. The aim of this work was to investigate
changes in the emission rate after the detection of echo signals.
The moth in tethered flight were stimulated by echo-like signals in 0.5 ms after the emission of their own click. This delay corresponds to the distance of 8 cm from some "virtual obstacle".
Such stimulation evoked increase of emission frequency immediately after the first echolocational contact which lasted during a few seconds from the detection of echo signals.
It was generally beleived that the hearing system of noctuid moths and related families had evolved for bat detection. The usage of hearing system by moth not only for their own echolocation but also for bat detection is quite possible since they use nearly the same frequency range (30-100 kHz).
In conclusion, stimulation of noctuid moths with stim-uli simulating the echo of their own clicks caused an increase in the average frequency of echolocation sig-nal emission. The use of this increase as a criterion of the insect's response to echo allowed us for the first time to demonstrate the capability for echolocation in moths Crino satura Schiff.
Original russian text published in Doklady Akademii Nauk, 1998. V.362, N 4. P.567-569.