The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), is an invasive pest affecting urban and rural communities, agricultural production and wildlife. Its complex biology and genetics is reflected in the existence of two different colony forms: monogyne and polygyne. We focus our studies on the polygyne form more abundant in Texas, characterized by the presence of multiple queens that co-operate for colony success. Our conceptual framework resides in the hypothesis that understanding gene networks linking nutrition and reproduction may reveal critical signaling pathways that could be disrupted to manage fire ants. In the pre-omics era we began by systematically cloning and characterizing the expression of genes and proteins important for reproduction and signaling and that we believe participate in the fire ant ‘genetic tool kit’. Our earlier studies focused on the vitellogenin receptor (VgR) and in the application of RNAi to reduce VgR gene expression as proof of principle that gene silencing in queens could lead to impaired egg production. Signaling systems related to reproduction and nutrition were also studied, such as the insulin receptors and the sNPF receptor, a G protein-coupled receptor. We have immunolocalized the sNPF receptor in the brain of queens and workers and found correlations in its neuronal gene expression in both castes with respect to the presence or absence of brood in the colony. We have generated and compared transcriptomes of mated and virgin queen brains and ovaries and identified a few differentially expressed genes. Most recently, with the release of the new fire ant genome in the Fall of 2018, we mined the genome to compile and curate the annotation of G protein-coupled receptors. The lecture will summarize key aspects of the biology of fire ants and morphological and functional differences among colony members. Experimental approaches utilized to begin to understand regulation of colony growth at the molecular level will be presented. It is our goal to unravel the endocrinological control of the fire ant colony with the hope of identifying novel targets to impair queen maturation, ovarian development, colony nutrition and brood production.

Reproduction is essential for the survival of a species and is under the close coordination of the central nerve system (CNS). In Drosophila melanogaster, juvenile hormones (JHs) from the corpora allatum(CA) are essential for egg-production because they promote vitellogenesis and enhance ecdysteroid biosynthesis. JH biosynthesis is under the control of neuropeptides, such as Drosophila insulin-like peptide (dilp) and allatostatin C (AstC). However, how these neuropeptide pathways coordinate JH production remain elusive. Here, we report a small number of neurons in the brain and ventral nerve cord (VNC) neurons that produce a neuropeptide AstC regulate egg-production negatively. The brain neurons seem to act indirectly by inhibiting secretion of dilp that up-regulates JH production, whereas the VNC neurons seem to release AstC into the hemolymph to suppress the CA activity directly. On the CA, the AstC actions appear mediated by two G-protein coupled receptors, AstC-R1 and AstC-R2. We will discuss our recent efforts to identify agonists for either receptor, which will be potential leads for insect reproduction regulators.