Effect of Exogenous Juvenile Hormone III and Precocene II on Agonistic Behavior and the Corpora Allata in Vitro Activity in the Male Lobster Cockroach Nauphoeta cinerea (Dictyoptera: Blaberidae, Oxyhaloinae)

In this study, the pharmacological effects of exogenous juvenile hormone III (JH III) and precocene II on agonistic behavior and corpora allata (CA) in vitro activity in the male lobster cockroach Nauphoeta cinerea were investigated. The probability of any control adult male adopting a dominant or subordinate status was 50:50, and the average onset of agonistic behavior occurred on the 9th day post emergence. Topical application of exogenous JH III, at a dose of 200 or 300 μg/male, did not affect the determination of social status. The proportions of dominants resulting from JH treatment and the acetone-control were 42%~47% and 53%~58%, respectively. Compared with the control insects, the onset of agonistic behavior was significantly delayed for 3 d in the JH-treated dominants and for 1 d in the acetone-treated dominants. Contrary to the results of JH treatment, a propensity for inhibition of a dominant status was induced by precocene II treatment. The proportion of dominants resulting from precocene II treatment was about 38% of that at a dose of 100 or 200 μg/male. Precocene II treatment also showed an acceleration effect on the onset of agonistic behavior, which was about 1 d earlier in the 200 μg precocene-treated dominants than in the control group. The corpora allata from dominants exhibited a significantly higher JH in vitro release rate than those of subordinates, regardless of whether they were JH-treated, precocene-treated, or non-treated controls.