Submitted to: Toxicon
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/9/2010
Publication Date: 3/12/2010
Publication URL: http://hdl.handle.net/10113/44908
Citation: Chen, J., Shang, H., Jin, X. 2010. Interspecific Variation of delta-1,6-piperideines in Imported Fire Ants. Toxicon. 55(2010)1181-1187. Interpretive Summary: Imported fire ants, including the red imported fire ant, Solenopsis invicta Buren, the black imported fire ants, S. richteri Forel, and the hybrid, S. invicta × S. richteri, are significant pest ants in the United States. They are a significant threat to public health due to the workers’ venomous stings. The reaction of human beings to the venom can sometimes be life threatening. Knowledge on the venom chemistry is critical in understanding the venom toxicology. DELTA-1,6-piperideines are newly identified alkaloids in fire ant venom. We have looked into the difference in the content of DELTA-1,6-piperideines among two species of imported fire ants and their hybrid. Hybrid workers contained significantly more DELTA-1,6-piperideines than their parent species. This research finding is important not only for understanding the mechanism of human reactions to fire ant stings and developing medical treatments for fire ant stings, but also for predicting the consequence of the hybridization in imported fire ants.
Technical Abstract: DELTA-1,6-piperideines have been recently reported in the venom of the red imported fire ants, Solenopsis invicta Buren and the black imported fire ants, S. richteri Forel. However, they have never been quantified in either species. Furthermore, there is no information available about those piperideines in the hybrid imported fire ants (S. invicta × S. richteri). The abundance of six DELTA-1,6-piperideines was investigated in both species and their hybrid using gas chromatography - mass spectrometer (GC-MS). They include 2-methyl-6-tridecenyl-6-piperideine, 2-methyl-6-pentadecenyl-6-piperideine, 2-methyl-6-heptadecenyl-6-piperideine, 2-methyl-6-tridecyl-6-piperideine, 2-methyl-6-pentadecyl-6-piperideine, and 2-methyl-6-heptadecyl-6-piperideine. S. invicta produced all six DELTA-1,6-piperideines, whereas, S. richteri did not produce 2-methyl-6-heptadecenyl-6-piperideine and 2-methyl-6-heptadecyl-6-piperideine. The DELTA-1,6-piperdiene profiles of the hybrid was similar to that of S. richteri, except trace amount of 2-methyl-6-heptadecenyl-6-piperideine and 2-methyl-6-heptadecyl-6-piperideine was found in some of the samples. The ratio of 2-methyl-6-pentadecenyl-6-piperideine to 2-methyl-6-pentadecenyl-6-piperideine (C15:1/C15:0) was significantly different among two species and their hybrid. In addition to DELTA-1,6-piperdienes, hybrid workers also contained significantly more piperidines than their parent species. This is the first evidence of heterosis of imported fire ants in venom production.