AUTHOR=Shi Qun-Hui , Hu Lin , Wang Wen-Kai , Vander Meer Robert K., Porter Sanford D., Chen Li 

TITLE=Workers and alate queens of Solenopsis geminata share qualitatively similar but quantitatively different venom alkaloid chemistry

JOURNAL=Frontiers in Ecology and Evolution

VOLUME=3

YEAR=2015

URL=https://www.frontiersin.org/journals/ecology-and-evolution/articles/10.3389/fevo.2015.00076

DOI=10.3389/fevo.2015.00076

ISSN=2296-701X

ABSTRACT=<p><italic>Solenopsis geminata</italic> group (Hymenoptera: Formicidae) encompasses ant species commonly called fire ants because of their painful sting. The many physiological effects of the venom are caused by 2-methyl-6-alkyl and/or alkenylpiperidine alkaloids. The variation in piperidine alkaloid structures has useful taxonomic characters. The most well studied <italic>Solenopsis</italic> species is <italic>Solenopsis invicta</italic>, which was accidentally imported into the USA in the 1930s from South America. It quickly spread throughout the southern USA and is now a major invasive pest ant in the USA and in other parts of the world. Interestingly, the invasive <italic>S. invicta</italic> has largely displaced a native USA fire ant, <italic>S. geminata</italic>, from the southern USA. We explore the possibility that differences in venom chemistry could be correlated with this displacement. The <italic>cis</italic> and <italic>trans</italic> alkaloids from body extracts of workers and alate queens of <italic>S. geminata</italic> were separated by silica gel chromatography, identified, and quantitated by GC-MS analysis. Both workers and alate queens produce primarily <italic>cis</italic>- and <italic>trans</italic>-2-methyl-6-<italic>n</italic>-undecylpiperidines, as well as other minor alkaloid components. Imported fire ant, <italic>S. invicta</italic>, alate queens produce the same alkaloids as <italic>S. geminata</italic> alate queens, but in contrast <italic>S. invicta</italic> workers produce piperidine alkaloids with longer side chains, which are purported to be physiologically more effective. These results are discussed in relation to the evolutionary progression of fire ant venom alkaloids and displacement of <italic>S. geminata</italic> by <italic>S. invicta</italic> in the USA.</p>