Semiochemical Release and Ontogenetic Changes in a Primary Scent Gland of Podisus maculiventris

The spined shoulder bug, Podisus maculiventris, is a generalist predator studied for its biocontrol potential. Despite our growing understanding of gland development, the conditions that elicit releases are largely unknown. To determine if male age or gland development affects the chemical composition and release behavior, we dissected adult male bugs and profiled the chemical composition of the male DAG 1, 7, and 14 d post-eclosion. To determine if gland development is related to sexual maturity, we counted the number of sperm present in the seminal vesicles at the same time points. Finally, we measured the diurnal release patterns of different aged males and in various male-female combinations. We observed that newly eclosed adults have under-developed glands and male seminal vesicles contained few sperm. One week post-eclosion the DAG contained previously reported semiochemical compounds and males contained many sperm. Mirroring the trend in reproductive maturation and gland development, the number of semiochemical releases increased with age and the majority of releases followed a scotophase pattern unaffected by sexual composition. These findings link male age to 1) dorsal abdominal gland development 2) release behavior and 3) sexual maturity, which will help our understanding of when these olfactory cues are present for other organisms, like prey, to perceive. Given the results, releasing adults that are at least 1 week post eclosion will maximize the non-consumptive effects of this biocontrol agent.

Automated summary

Through dissecting adult male bugs and analyzing the chemical composition, it was found that the release behavior of the spined shoulder bug is related to male age, gland development, and sexual maturity. The developmental trend of reproductive glands and the number of semiochemical releases increased with age, while the sexual composition did not affect the release behavior. These findings have important implications for understanding the timing of olfactory cues perception in other organisms, such as prey.