Diapause induction in Trichogramma telengai: the dynamics of maternal thermosensitivity

Abstract

AbstractTransferring Trichogramma telengai Sorokina (Hymenoptera: Trichogrammatidae) from 17 to 30 °C or vice versa at different stages of pre‐imaginal development shows that the pupa (particularly late pupa) is a sensitive stage of the maternal thermal response. During this period, even a relatively short period (1–2 days) of cold or heat exposure results, correspondingly, in a marked increase or decrease in the percentage of diapausing progeny. Thus, the maternal thermal response has the same features of sensitivity as those of the previously investigated maternal photoperiodic response, suggesting that photoperiodic and thermal responses share the same mechanism. For the practice of rearing and storage Trichogramma as a biocontrol agent, it is important to note that even relatively short‐term environmental heating (i.e. for one to several days) immediately before adult emergence can drastically decrease the percentage of diapausing progeny.