The regulation of vitellogenin transcripts in the worker caste of the red imported fire ant (Solenopsis invicta)

After its introduction to the USA in 1930 the red imported fire ant has become an increasingly significant medical, agricultural and economical pest, and there is an urgent need to find novel pest control strategies. Vitellogenesis is a key process in the reproduction of insects, and functional characterization of its building blocks could thus be great targets for insect control. Insect vitellogenins (Vg) are large glycoproteins involved in vitellogenesis. Juvenile hormone (JH) and/or ecdysone are the main inducers of vitellogenin (Vg) synthesis from the fat body and Vg uptake into the developing oocyte. In bees, Vg titer has been associated with task allocation in workers. Interestingly, four Vg genes (Vg1, Vg2, Vg3 and Vg4) have been identified in the fire ant genome, with Vg1 and Vg4 primarily expressed in the workers while Vg2 and Vg3 are expressed in the queen. The sterile worker castes are responsible for sustaining the entire colony through collecting food sources for queen and larvae, protecting the nest and caring for brood. Since they do not possess ovaries, functional characterization of Vg function in workers could be crucial for pest control as it may disrupt their task allocation. In this study we evaluated the expression of all Vg transcripts in workers, queens and males. Using RT-qPCR we identified differential expression of Vg transcripts and we assessed the role JH plays in Vg expression using the JH analogue, hydroprene.