Semiochemicals Released by Electrically Stimulated Red Imported Fire Ants, Solenopsis invicta
The red imported fire ant Solenopsis invicta Buren, has evolved sophisticated chemical communication systems that regulate the activities of the colony. Among these are recruitment pheromones that effectively attract and stimulate workers to follow a trail to food or alternative nesting sites. Alarm pheromones alert, activate, and attract workers to intruders or other disturbances. The attraction and accumulation of fire ant workers in electrical equipment may be explained by their release of pheromones that draw additional worker ants into the electrical contacts. We used chemical analysis and behavioral bioassays to investigate if semiochemicals were released by electrically shocked fire ants. Workers were subjected to a 120 V, alternating-current power source. In all cases, electrically stimulated workers released venom alkaloids as revealed by gas chromatography. We also demonstrated the release of alarm pheromones and recruitment pheromones that elicited attraction and orientation. Arrestant behavior was observed with the workers not electrically stimulated but near those that were, indicating release of unkown behavior-modifying substances from the electrically stimulated ants. It appears that fire ants respond to electrical stimulus by generally releasing exocrine gland products. The behaviors associated with these products support the hypothesis that the accumulation of fire ants in electrical equipment is the result of a foraging worker finding and closing electrical contacts, then releasing exocrine gland products that attract other workers to the site, who in turn are electrically stimulated.
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- Banks, W. A., Lofgren, C. S., Jouvenaz, D. P., Stringer, C. E., Bishop, P. M., Williams, D. F., Wojcik, D. P., and Glancey, B. M. 1981. Techniques for Collecting, Rearing, and Handling Imported Fire Ants. US. Dept. Agric., Sci. Ed. Admin. AAT-S-21:1–9.Google Scholar
- Greenberg, L., Fletcher, D. J. C., and Vinson, S. B. 1985. Differences in worker size and mound distribution in monogynous and polygynous colonies of the fire ant Solenopsis invicta Buren. J. Kans. Entomol. Soc. 58:9–18.Google Scholar
- Lofgren, C. S. 1986. The economic importance and control of imported fire ants in the United States, pp. 227–256, in S. B. Vinson (ed.). Economic Impact and Control of Social Insects. Praeger, New York.Google Scholar
- MacKay, W. P., Majdi, S. O., Vinson, S. B., Messer, C. J., and Irving, J. P. 1989. Prevention of fire ant damage to signal control. Research Report 1135–2F. Texas Transportation Institute, Texas A and M University, College Station, Texas.Google Scholar
- MacKay, W. P., Vinson, S. B., Irving, J., Majdi, S., and Messer, C. 1992a. Effect of electrical fields on the behavior of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). Environ. Entomol. 21:866–870.Google Scholar
- MacKay, W. P., Majdi, S., Irving, J., Vinson, S. B., and Messer, C. 1992b. Attraction of ants (Hymenoptera, Formicidae) to electric fields. J. Kans. Entomol. Soc. 65:39–43.Google Scholar
- Sokal, R. R. and Rohlf, F. J. 1981. Biometry, 2nd ed. W. H. Freeman, New York, 859 pp.Google Scholar
- Soroker, V., Vienne, C., Hefetz, A., and Nowbahari, E. 1994. The postpharyngeal gland as a “Gestalt” organ for nestmate recognition in the ant Cataglyphis niger. Naturwissenschaften 81:510–513.Google Scholar
- Tschinkel, W. R. 1987. The fire ant, Solenopsis invicta, as a successful “weed, ” pp. 585–588, in J. Eder and H. Rembold (eds.). Chemistry and Biology of Social Insects, Verlag J. Peperny, Munich, 757 pp.Google Scholar
- Vander Meer, R. K. 1986. The trail pheromone complex of Solenopsis invicta and Solenopsis richteri, pp. 201–210, in C. S. Lofgren and R. K. Vander Meer (eds.). Fire Ants and Leaf-Cutting Ants: Biology and Management, Westview Press, Boulder, Colorado, 435 pp.Google Scholar
- Vander Meer, R. K. and Alonso, L. E. 1998. Pheromone directed behavior in ants, pp. 159–192, in R. K. Vander Meer, M. Breed, M. Winston, and K. E. Espelie (eds.). Pheromone Communication in Social Insects. Westview Press, Boulder, Colorado, 368 pp.Google Scholar
- Vander Meer, R. K. and Morel, L. 1988. Brood pheromones in ants, pp. 491–513, in J. C. Trager (ed.). Advances in Myrmecology. E. J. Brill, New York, 551 pp.Google Scholar
- Vinson, S. B. and Mac Kay, W. P. 1990. Effects of the fire ant, Solenopsis invicta, on electrical circuits and equipment, pp. 496–503, in R. K. Vander Meer, K. Jaffe, and A. Cedeno (eds.). Applied Myrmecology: A World Perspective. Westview Press, Boulder, Colorado, 741 pp.Google Scholar