Social facilitation affecting tolerance to poisoning in termites (Insecta,Isoptera)

Previous works have shown that social interactions may enhance termite abil ity to overcome physiological stresses such as starvation and disease. We e valuated the effects of group size on termite tolerance to poisoning, by su bmitting groups of Cornitermes cumulans workers to an organophosphorus inse cticide (chlorpyrifos). Survival of both, poisoned and non-poisoned termite s, depended on the number of individuals in the group, presenting a peak at an density around 8 individuals/test tube. Survival of poisoned termites, however, showed a peak much lower than that of non-poisoned termites. We co nclude, therefore, that socially induced ability to overcome physiological stresses in termites may be expressed even under "non-natural" stresses, su ch as poisoning by insecticides. The mechanisms leading to such a result re main to be investigated. It seems, however, that social facilitation may en hance (or trigger) biochemical and/or neurophysiological mechanisms that co llaterally may help in the detoxification of insecticides in termites. In a ddition, we warn that laboratory experiments with termites/insecticide may be severely affected by the group size being tested.