FEEDING IS NOT NECESSARY FOR TRIGGERING PLASTICIZATION OF THE ABDOMINAL CUTICLE IN HEMATOPHAGOUS BUGS

A simple device was used to quantify changes in the mechanical propert ies of the cuticle of Rhodnius prolixus and Triatoma infestans that ta ke place when these insects feed, i.e., plasticization. Different stim uli were presented for 1 min to test for their ability to trigger plas ticization. These were: a blood meal, a Ringer solution meal, contact with a warm surface and thermal stimulation without such contact. Our results supplant any previous hypotheses that have supposed that the p resence of food in the alimentary tract is necessary to evoke plastici zation. We find that mere contact of the proboscis with a warm surface (without any food intake) is sufficient to trigger plasticization ind istinguishable from that produced by a blood meal. Thermal stimulation alone, i.e., without physical contact, was not effective. (C) 1998 El sevier Science Ltd. All rights reserved.