Constant temperatures between 32–35°C or higher and fluctuating temperatures with a mean of 32°C or higher generally resulted in reproductive failure of pink bollworms,Pectinophora gossypiella(Saunders), if the exposure occurred in the larval and pupal, pupal, or adult stages. This failure usually occurred because the male exposed to high temperature did not mate and/or effectively transfer sperm to the spermatheca of the female. Short exposures to high temperature in the late larval-early pupal stage caused mortality but had little effect on reproduction. Sperm was often found in the transferred spermatophores, an indication that death of the sperm, reduced sperm motility, or some other mechanism prevented movement of sperm to the spermatheca. Both eupyrene and apyrene sperm were affected. Females exposed to these temperatures had reduced egg laying and egg viability.