Differential gene expression in Red Imported Fire Ant (Solenopsis invicta) (Hymenoptera: Formicidae) larval and pupal stages

Authors: Allen, Margaret - Meg; Rhoades, Joshua; Sparks, Michael; Grodowitz, Michael

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/29/2018
Publication Date: 12/5/2018
Publication URL: https://handle.nal.usda.gov/10113/6471027
Citation: Allen, M.L., Rhoades, J.H., Sparks, M., Grodowitz, M.J. 2018. Differential gene expression in Red Imported Fire Ant (Solenopsis invicta) (Hymenoptera: Formicidae) larval and pupal stages. Insects. 9(4):185.

Interpretive Summary: Red imported fire ants are invasive biting and stinging pests, and are very difficult to control. A novel pest control method involving the interruption of gene activity could help subdue this pest. To assist in choosing vital candidate genes for interruption, a comparison of genes active during critical insect development stages—specifically, the larval and pupal stadia—was performed. The larva serve a vital role in the colony by performing the majority of digestion of complex foods, and this stadium constitutes the insect’s most active life stage. The pupa stage immediately follows the larva, and because this stadium is critical to development but does not feed, it was used for comparison. Modern sequencing technology was used to identify genes and compare the two stages. From the thousands of sequenced genes investigated, various gene interruption targets were identified for disrupting vital life processes.

Technical Abstract: Solenopsis invicta is an invasive species that has been introduced to multiple continents. One such area, the southern United States, has a tragic history of multiple unsuccessful control projects using powerful pesticides over vast ranges, resulting in substantial non-target effects across trophic levels. With the advent of next generation sequencing and RNAi technology, new control methods are available. A robust genome-guided transcriptome assembly was used to investigate gene expression differences between S. invicta larvae and pupae. These life stages differ in many physiological processes; of special importance is the vital role of S. invicta larvae as the colonies’ “communal gut.” Differentially expressed transcripts were identified related to many important physiological processes, including digestion, development, cell regulation and hormone signaling. This dataset provides essential developmental knowledge that reveals the dramatic changes in gene expression associated with social insect life stage roles, and can be leveraged using RNAi to develop effective control methods.