FACTORS ELICITING STRIDULATION BY THE PONERINE ANT STREBLOGNATHUS-AETHIOPICUS SMITH (HYMENOPTERA, FORMICIDAE)

Workers of Streblognathus aethiopicus Smith stridulated when grasped o r when either mammalian breath or carbon dioxide was directed onto the m. The ants did not react when subjected to air or nitrogen treatments and only occasionally responded to a stridulating nestmate. The sound produced by individual stridulating ants was analysed using a sonagra m, while ablation experiments suggested that carbon dioxide receptors were positioned on the antennae. Scanning electron micrographs were us ed to examine the stridulatory apparatus and the putative carbon dioxi de receptors on the antenna. Stridulation was usually associated with increased ant activity which included the aggressive opening of the ma ndibles, waving of the antennae and the positioning of the abdomen und er the body when ready to sting. Streblognathus aethiopicus appeared t o use stridulation to warn potential predators of their presence befor e they have to protect themselves by means of their powerful mandibles and potent sting. It is proposed that the purpose of sound production by S. aethiopicus is primarily defensive.