|Anderson, James - USDA, ARS, CMAVE|
|Vander Meer, Robert|
Submitted to: Imported Fire Ants Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 25, 2001
Publication Date: March 5, 2001
Citation: Anderson, J.B., Vander Meer, R.K. 2001. Experimental Evidence Against Cuticular Hydrocarbons as Nestmate Recognition Cues in the Fire Ant Solenopsis invicta. 2001 Imported Fire Ants Conference Proceedings. p. 69-70. San Antonio, Texas. February 28-March 2, 2001. Technical Abstract: In the present study we designed experiments (1) to confirm the finding that ants circulate and blend together their collective cuticular hydrocarbon mixture and (2) to test the hypothesis that cuticular hydrocarbons function as nestmate recognition cues in the Red Imported Fire Ant, Solenopsis invicta. We applied pure synthesized hydrocarbon to the body surface of a large worker fire ant, and then isolated this 'painted ant' with smaller workers from the same mother colony. We predicted that the ants of each isolated group would spread the hydrocarbon treatment around over time to each other by trophallaxis, grooming and physical contact, producing a range of deviations from the normal colony composition of hydrocarbons. At intervals during the course of the experiments, ants were removed, 'tested' back in their mother colony to see if they were recognized as 'alien', and subsequently assayed for hydrocarbon profile. Logically, if the cuticular hydrocarbon composition functions as a nestmat recognition cue, ants with a composition which deviated from the norm should elicit an aggressive response when tested back in the mother colony (recognition as alien by former nestmates). A variation in hydrocarbon composition was successfully produced in the experimentally treated groups. However, we found no significant correlation of aggression scores with deviation from the mean hydrocarbon composition of individual ants. These results do not support the hypothesis that cuticular hydrocarbons function as nestmate recognition cues in S. invicta. Other lipid compounds in the mixture, from both genetic sources (pheromones, exocrine gland secretions) and environmental influences (food type, soil chemistry, local ecology) are implicated as the salient recognition discriminators for this species.