Chemical Characterization of Red Imported Fire Ants with Colony Development

Authors: Chen, Jian

Submitted to: Journal of Infectious Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2024
Publication Date: 7/5/2024
Citation: Chen, J. 2024. Chemical Characterization of Red Imported Fire Ants with Colony Development. Journal of Infectious Diseases. 2024;5(1):35-43.

Interpretive Summary: Fire ants are well known for their venomous and painful stings, which can pose a threat to public health. Scientists have been studying the venom chemistry to understand how it affects people and how to treat fire ant stings effectively. However, most studies have focused on ants from mature colonies, neglecting the dynamics of chemical compositions with the colony development. In this study, researchers looked at how the chemicals in fire ant venom change as a colony of ants grows. They found that the venom produced by ants in incipient colonies is simpler compared to that of ants in older colonies. As the colony matures, the venom becomes more complex, containing different types of chemicals. Overall, this study gives us important insights into the chemicals that make up fire ant venom and how they change over time. Understanding these changes could lead to better treatments for fire ant stings in the future.

Technical Abstract: The red imported fire ant, Solenopsis invicta Buren, poses a significant threat to public health due to its venomous stings. While the chemistry of the fire ants has been well investigated, most studies have focused on ants from mature colonies, overlooking the dynamic changes in chemical compositions during colony development. In this study, we established S. invicta colonies using newly collected queens from the field and then tracked the chemistry of workers as the colonies developed. Our findings reveal that the chemical profile of worker ants in incipient colonies (the minor workers) is much simpler compared to workers in mature colonies, which are dominated by trans-2-methyl-6-tridecenylpiperdine (trans-C13:1-piperidine). Initially, trans-C13:1-piperidine could account for up to 98% of all detected alkaloids; however, its percentage gradually decreased with colony development due to the increase of other alkaloids. During days 50 to 100, production peaks in trans- and cis-2-methyl-6-undecylpiperidines (trans- and cis-C11-piperidine) were consistently observed. Piperidene and pyridine alkaloids were also detected within two months of colony age; however, piperidine alkaloids were always the first to appear, followed by piperidene and pyridine alkaloids. In addition to Z,E-a-farnesene, Z,E-a-homofarnesene, Z,Z-a-homofarnesene, heptadecane, and nanodecane, five geranyl esters of fatty acids were identified. As expected, the origin of these compounds was Dufours’ gland. Although these compounds were consistently detected in sting extractions, they seldom appeared in milked venom (2 of 30 cases). These compounds may be unique to fire ants in the early stages of colony development.