The survival of Triatoma infestans and of somatic cells from this species i
s affected by heat shock. In this study, we examined the cell death respons
es of male germ line cells from 5th instar nymphs 7 and 30 days after heat
shock exposure (40 degrees C, 1 h). The preparations were stained by the Fe
ulgen reaction and the TUNEL immunocytochemical assay. Apoptosis was elicit
ed by heat shock, with positive TUNEL responses in spermatogonial chromatin
and chromosomes, spermatids and sperm cells. Spermatogonia were most affec
ted seven days after the shack whereas some spermatids and sperm cells exhi
bited DNA fragmentation only thirty days after heat shack. The rate of cell
death varied among the cells. In some cases, cellular differentiation was
unaffected by heat shock, with DNA fragmentation occurring towards the end
of spermatogenesis.