Examining the genetic basis for a phenotypic change in the red shouldered soapberry bug, Jadera haematoloma

The red shouldered soapberry bug Jadera haematoloma (Heteroptera:Rhopalidae) has provided an unique opportunity to study the genetic basis for phenotypic differences between populations. Among J. haematoloma in Southern Florida, individuals are found feeding and reproducing on the native balloon vine (Cardiospermum sp.). Recently derived (~60 years) populations also feed on goldenrain tree (Koelreuteria sp.). As a result of this host shift, rostrum length in derived J. haematoloma has declined from almost 70% of body length to roughly 50%. This study looks into the development of the mouthparts, focusing on three genes- Distal-less, dachshund, and homothorax known to play a role in the mouthpart development in another heteropteran, Oncopeltus fasciatus. RNA interference was used to characterize the roles of these genes in J. haematoloma mouthpart development. Treatment groups for all the genes resulted in phenotypic differences from the control group. Maternal RNAi for Dll resulted in hatchlings without proper appendage development. Juvenile RNAi showed that Dll significantly reduced labrum length and dac showed a significant reduction in labium segment 3 and 4. It has been concluded that Distal-less, dachshund, and homothorax play a developmental role in J. haematoloma mouthparts and that the genes have a conserved function between species.