Worms, Rats And Mice Have Warning Systems

Press, Volume CVIII, Issue 31764, 22 August 1968, Page 20

Worms, Rats And Mice Have Warning Systems

(By WALTER SULLIVAN) Rats, mice and worms appear to communicate with one another in ways unsuspected heretofore. This is indicated by three independent reports in the current issue of the journal “Science.” One report, by four researchers from the department of psychology at the University of Wisconsin, tells how earthworms subjected to stress by pinching, handling or electric shock exude a mucus that, when dried,

serves as a stay-away warning to other worms. It is just as effective three months later as a few hours after ut retion.

They point out that worms habitually secrete the mucus from all segments of their bodies, possibly as a lubricant and also to cement soil particles along the walls of their burrows. When alarmed the worms seem to include a “message chemical” in this mucus—what' biologists call a pheronone. The experimenters also subjected worms to electric shock. They found that other worms fled areas where the worms under shock had been. No such panic was observed

in worms in areas where unshocked worms had passed. It is suspected that the “alarm chemical” shown by these tests may have influenced earlier experiments. Worms that seemed to be learning their way through a maze may actually have “learned” where not to go from other worms.

Tests reported by two scientists from Rockhurst College in Kansas City suggest that rats may also exude an alarm chemical. Hitherto no such substance has been identified in mammals. The scientists found that hungry rats, trained to press a bar to obtain food, did so assiduously until they smelled rats that were under stress. No such interruption of feeding occurred if the smell was from rats not under stress. In the case of mice it appears that males produce an odour that stimulates females to undergo the hormonal changes that prepare them for sexual intercourse, producing the condition known as estrus.

This is reported by a team of three at the Jackson Laboratory in Bar Harbour, Maine. It had been suspected that the urine of male mice had such an effect, but it was not known that the stimulant was volatile, acting through the nose of the female. A recent article in the British journal “Nature” notes that those researchers who wish to reduce the odour in their mouse quarters should clean them rarely. The strongest - smelling mouse cages, it said, are those cleaned daily.