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

Author
item SHI, QUN-HUI - Yangtze University
item HU, LIN - Yangtze University
item WANG, WEN-KAI - Yangtze University
item Porter, Sanford
item Vander Meer, Robert - Bob
item CHEN, LI - Chinese Academy Of Sciences

Submitted to: Frontiers in Ecology and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2015
Publication Date: 7/22/2015
Citation: Shi, Q., Hu, L., Wang, W., Porter, S.D., Vander Meer, R.K., Chen, L. 2015. Workers and alate queens of Solenopsis geminata share qualitatively similar but quantitatively different venom alkaloid chemistry. Frontiers in Ecology and Evolution. 3:76.

Interpretive Summary: Imported fire ants infest more than 320 million acres in 13 southern tier states and Puerto Rico and are spreading northward. This invasive ant is estimated to be responsible for almost $7 billion annually in damage repair, medical care, and control costs. The affected economic sectors are broad ranging and include households, electric service and communications, agriculture (crops and livestock), schools and recreation areas. Interestingly, ants comprise 5% of the world’s 100 worst invasive alien species, and of the 17 land invertebrates listed, 28% are ants, including fire ants! In the last decade S. invicta has changed from an invasive pest ant in the United States to a global problem, with infestations occurring in Australia Taiwan, mainland China, Mexico, and many Caribbean Island countries. A native fire ant, S. geminata, is less aggressive and its sting is less painful, but it has been largely displaced by S. invicta. Scientists at the Center for Medical, Agricultural and Veterinary Entomology, USDA, ARS, Gainesville, Florida USA, Institute of Zoology, the Chinese Academy of Sciences, Beijing, China, and the School of Agriculture, Yangtze University, Jingzhouthe, China investigated the venom composition of S. geminata to better understand the population dynamics of this native species and the imported S. invicta. It was concluded from venom profiles that S. geminata is a less evolved Solenopsis species, since worker and female sexual venom alkaloids are similar, whereas in S. invicta worker alkaloid composition evolved to a more complicated and more effective venom alkaloid composition then that of female sexuals. This is one factor that likely contributes to the displacement of S. geminata by S. invicta.

Technical Abstract: The cis and trans alkaloids from body extracts of workers and alate queens of the tropical fire ant, Solenopsis geminata (Hymenoptera: Formicidae), were successfully separated by silica gel chromatography, identified, and quantitated by GC-MS analysis. Both workers and alate queens produce primarily (2R,6S)-2-methyl-6-n-undecyl-piperidine (cis-C11) and (2R,6R)-2-methyl-6-n-undecyl-piperidine (trans-C11). In addition, three pairs of cis and trans isomer homologues, 11:1, C13:1, C13, and two piperideines, 2-methyl-6-n-undecyl-'1,6-piperideine and 2-methyl-6-n-undecyl-'1,2-piperideine, were identified as minor components. The ratios of cis-C11 to trans-C11 ranged from 0.36 to 0.67 in workers. However, alate queens produce significantly more cis-C11 and less trans-C11 than workers, resulting in significantly higher ratio of cis-C11 to trans-C11 in alate queens than in workers. The results obtained from both workers and alate queens were discussed in relation to the evolutionary progression of fire ant venom alkaloids.