Sex-specific expression profiles of ecdysteroid biosynthesis and ecdysone response genes in extreme sexual dimorphism of the mealybug Planococcus kraunhiae (Kuwana).

Insect molting hormone (ecdysteroids) and juvenile hormone regulate molting and metamorphic events in a variety of insect species. Mealybugs undergo sexually dimorphic metamorphosis: males develop into winged adults through non-feeding, pupa-like stages called prepupa and pupa, while females emerge as neotenic wingless adults. We previously demonstrated, in the Japanese mealybug Planococcus kraunhiae (Kuwana), that the juvenile hormone titer is higher in males than in females at the end of the juvenile stage, which suggests that juvenile hormone may regulate male-specific adult morphogenesis.

E93 expression and links to the juvenile hormone in hemipteran mealybugs with insights on female neoteny.

Insect metamorphosis produces reproductive adults and is commonly accompanied with the direct or indirect development of wings. In some winged insects, the imago is altered by life history changes. For instance, in scale insects and mealybugs, reproductive females retain juvenile features and are wingless.

Differential Juvenile Hormone Variations in Scale Insect Extreme Sexual Dimorphism.

Scale insects have evolved extreme sexual dimorphism, as demonstrated by sedentary juvenile-like females and ephemeral winged males. This dimorphism is established during the post-embryonic development; however, the underlying regulatory mechanisms have not yet been examined. We herein assessed the role of juvenile hormone (JH) on the diverging developmental pathways occurring in the male and female Japanese mealybug Planococcus kraunhiae (Kuwana).