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Aug 2016: Started as a Ph.D. student in the Ross lab at the University of Georgia-Athens.
Project (1): Investigate key components in the polygyne queen of Solenopsis invicta (red imported fire ant) that mediate worker supergene discrimination
Publication: Zeng, H., Millar, J. G., Chen, L., Keller, L., & Ross, K. G. (2021). Characterization of Queen Supergene Pheromone in the Red Imported Fire Ant Using Worker Discrimination Assays. Journal of Chemical Ecology, 1-12. https://link.springer.com/article/10.1007/s10886-021-01336-0
Abstract: Social organization in the red imported fire ant, Solenopsis invicta, is determined by the Sb supergene, with colonies of the monogyne (single-queen) form lacking the element and colonies of the polygyne (multiple-queen) form possessing it. Polygyne workers accept new reproductive queens in their nest, but only those carrying Sb; young winged queens lacking this genetic element are executed as they mature sexually in their natal nest or as they attempt to enter a foreign nest to initiate reproduction after mating and shedding their wings. It has been suggested that queen supergene genotype status is signaled to workers by unsaturated cuticular hydrocarbons, while queen reproductive status is signaled by piperidines (venom alkaloids). We used high-throughput behavioral assays to study worker acceptance of paper dummies dosed with fractions of extracts of polygyne queens, or blends of synthetic counterparts of queen cuticular compounds. We show that the queen supergene pheromone comprises a blend of monoene and diene unsaturated hydrocarbons. Our assays also reveal that unsaturated hydrocarbons elicit discrimination by polygyne workers only when associated with additional compounds that signal queen fertility. This synergistic effect was obtained with a polar fraction of queen extracts, but not by the piperidine alkaloids, suggesting that the chemical(s) indicating queen reproductive status are compounds more polar than cuticular hydrocarbons but are not the piperidine alkaloids. Our results advance understanding of the role of chemical signaling that is central to the regulation of social organization in an important invasive pest and model ant species.
Project (2): Investigate how Sb workers influence the collective queen preference of the whole colony
@ ILLINOIS (undergraduate)
Sep 2015 – April 2016 WithMatias Fernandez, Dr. Katy Heath, University of Illinois, individual project IB490, Searching for selection for higher wind dispersal ability in western redcedar in the Pacific Northwest. (Poster)
Sep 2014 – Jan 2015 With Dr. Chris Dietrich and Dr. David Zaya, University of Illinois, individual project IB390, The relationships between Auchenorrhyncha insect diversity and vegetation community composition in Illinois
Summer research 2014: with Dr. Brenda Molano-Flores & Dr. David Zaya, National Great Rivers Research and Education Center, The relationship between reproduction, photosynthetic traits, and genome size for a rare Illinois plant species along the Mississippi River” (Poster)