SIGNALLING AMONGST INSECTS.

Mt Benger Mail, 11 March 1914, Page 3

SIGNALLING AMONGST INSECTS.

Proie&sor J. Arthur Thomson discusses, in 'Knowledge,' Professor Buguion's' interesting observations in signalling among whke ants. He found that the noise is produced by the oldiers, who knock on dry leaves or the like, with their mandibles. A cobra,ike hissing, as is seemed at first, was traced to a colony which had formed itt i?a.leries on the big fallen leaves of the uread tree. Prom a colony in Bugniou's office desk answers used to he got to outside baps. In another experiment, a piece oi termitary was placed on a big ; ,ate and covered with stiff paper; tlw soldiers collected on the under surface of the paper, and answered back to every vioration. Hie noise differs in

different species, '.-ub is always due to oiinute blows on a resonating surface. ' I lie result niay bo a rustling, or a rattling, or a cracking) or otherwise. In an Indian species the noise made by the iarge and aggressive workers wnen they are disturbed is like the crackling oi withered leaves trodden underfoot. I'lieiv is evidence that the noise or the associated vibrations serve to wain the workers or to reassure and encourage them. There seems little doubt but that they are of the nature of .- .. lis. Thar .sounds or vibrations are really perceived is made clear by what was seen in. 'he field, by ti o responses given by the tenants of Bugnion's desk to taps from without, and by thediscoverj of an important sensory organ, which is probably particularly sensitive to the vibrations of a material like the framework of a leaf or branch, the wooden partitions of the termitary, the dj;. walls of the fungus growing labyrinths. and so on. It. is too soon to ask how much is auditory and how much fineh tactile. The audible signalling is to be distinguished from another kind of signalling- a soundless signalling —which seems to bo common among termites. If is curiously lika anil unlike military saluting; for it seems that the soldreis salute the workers. So far as we kno v both soldiers and workers are sexually immature individuals of both sexes, lli.t this requires looking into. In the soundless signalling the insect staads firmly on its legs, with the head raised and the body slightly oblique, and -hakes itself for an instant with a convulsive shiver- This seems to mean something to the parsing worker. We oannot get physchologically near enough ' to say more.