CHANGES IN MALE TRIATOMA-INFESTANS REPRODUCTIVE EFFICIENCY CAUSED BY A SUBOPTIMAL TEMPERATURE

In Triatoma infestans, reproductive capacity seems to be one of the pr ocesses most sensitive to low temperatures. Because suboptimal tempera tures are very frequent in endemic areas for Chagas' disease, the aim of this work was to determine the effect of suboptimal temperature on reproductive efficiency of male T. infestans, its possible correlation with blood consumption, and the reversibility of these changes. The e xperiments were carried out on fifth-instar nymphs and adults exposed to a temperature of 12-degrees-C for 10 days. In order to evaluate the reversibility of the changes the insects were then exposed to 28-degr ees-C after experiencing the cold period. In nymphs, gametic cell prol iferation decreased under low temperature and spermatid production was inhibited. These effects were reversed at optimal temperature. In adu lts, a decrease in male accessory gland secretion was induced under lo w temperatures and this was directly related to blood consumption redu ction. In spite of the recovery of mating behaviour, the accessory gla nds continued to produce inadequate quantities of secretion. Consequen tly, small spermatophores were produced and a diminution in fertility was observed.