HEARING IN INSECTS.

Daily Telegraph (Napier), Issue 3506, 2 October 1882, Page 4

HEARING IN INSECTS.

The sense of hearing in insects has been recently studied by Herr Gruber. Of airinsects he found the cockroach (Blalia Germanica) very sensitive. On sounding a violin-note, when a cockroach was running across the floor, the creature always suddenly stopped. Again, a number of these cockroaches were enclosed in a glass vessel, and on making a strong sound, there was evident agitation and excitement; some would fall down from the glass, as if paralysed. A cockroach was hung by a thread from its hind l?g ; when it was quiet, a bow was drawn sharply over the violin strings afc the distance of aboufc 4 feefc, whereupon the insect; was greatly excited, and struggled round, getting its head uppermost. Beetles also were readily affected by sounds ; bufc grubs and ants gave no certain indications. Of aquatic insects, various kinds of Corixa ■were tried. These would often remain quite quiet for several minutes, bufc on tapping the glass with a glass tube, they rushed about in much agitation. A disc at the end of a long md, drawn to and fro in the water near a quiet Corixa produced no effect; bufc on conducting the sound of a struck bell into the liquid by the rod, there was lively reaction; similarly, when a glass bell, stroked with a bow, was brought to touch the water. 1 hese creatures were also sensitive to high violin notes in air, to the sound of a metal plate struck with a hammer, &c. Still more sensitive to sound were various aquatic beetles (Laccophilus, Laccobius,Nepa cinerea, ko.) On the other hand, various larva?, especially of ephernerides, were unaffected ; but these were sensitive to mechanical agitation of the water. Herr Gruber .onsiders the response the insects made to sound an indication of true hearing, and not mere reflex action.