Meeting Abstract
Scale insects are important plant pests with a peculiar post-embryonic development leading to an extreme sexual dimorphism. The wingless juvenile-like adult females result from traditional hemimetabolous development, whereas males develop through neometaboly, a type of metamorphosis including quiescent non-feeding stages where wings and other adult features develop. The latter is reminiscent to complete metamorphosis and its understanding would provide insights into the evolution of holometaboly . Our study aimed at examining the potential role of the juvenile hormone (JH) in this sexual dimorphism and wing development in males. We assessed the expression profiles of genes involved in JH signaling pathway during male and female development of the Japanese mealybug, Planococcus kraunhiae (Kuwana) (Pseudococcidae). Quantitative RT-PCR of JH receptor and partner Methoprene-tolerant and Taiman, as well as early response genes Krüppel-homolog1 and Broad showed notable differences, especially during the embryonic stage and from the middle of the second-instar nymph, when males and females start to differentiate. JH analogue treatment on male quiescent stages allowed to identify the Broad copy and isoform involved in JH signaling. Our results suggest that JH may play a role in the sexual differentiation in mealybug post-embryonic development.
