Factors Affecting Thanatosis in the Braconid Parasitoid Wasp Heterospilus prosopidis

SIMPLE SUMMARY: Thanatosis is an antipredator behavior widely recognized in insects, but our knowledge of this behavior in Hymenoptera is insufficient. We examined the effects of sex, age, temperature, and background color on thanatosis in the parasitoid wasp Heterospilus prosopidis under laboratory conditions, and found that some of these factors have significant effects on thanatosis of this species. ABSTRACT: Thanatosis, also called death feigning, is often an antipredator behavior. In insects, it has been reported from species of various orders, but knowledge of this behavior in Hymenoptera is insufficient. This study examined the effects of sex, age (0 or 2 days old), temperature (18 or 25 °C), and background color (white, green, or brown) on thanatosis in the braconid parasitoid wasp Heterospilus prosopidis. Thanatosis was more frequent in 0-d-old individuals and in females at 18 °C. The duration of thanatosis was longer in females, but this effect of sex was weaker at 18 °C and in 0-d-old individuals. The background color affected neither the frequency nor duration. These results were compared with reports for other insects and predictions based on the life history of this species, and are discussed from an ecological perspective.