Wednesday, December 12, 2007
D0492

Comparative electroantennogram response of two phorid fly species to different species of imported fire ant

Li Chen, lichen_1973@yahoo.com, Auburn University, Department of Entomology and Plant Pathology, 301 Funchess Hall, Auburn University, Auburn, AL, Samuel Ochieng, sochieng@blomand.net, Tennessee State University, Institute of Agricultural and Environmental Research, Otis L. Floyd Nursery Research Center, 472 Cadillac Lane, McMinnville, TN, and Henry Y. Fadamiro, FADAMHY@auburn.edu, Auburn University, Department of Entomology & Plant Pathology, 346 Funchess Hall, Auburn, AL.

Parasitoids of ants may utilize pheromonal signals used in intraspecific communication among ant individuals as kairomones for host location. To better understand the host preference of phorid fly to the imported fire ants, we compared the electroantennogram (EAG) responses of both sexes of the two released phorid species to varying doses of three different imported fire ants: red, black and hybrid imported fire ants, S. invicta, S. richteri, and S. invicta * S. richteri, respectively. The data showed a significant effect of sex on EAG responses of both parasitoids. Females of both species generally showed significantly greater EAG response than conspecific males to the three fire ant extracts, suggesting that female parasitoids are more responsive than conspecific males to all three fire ant species. In general, P. tricuspis females and males showed greater EAG response than counterpart P. curvatus to all three fire ant extracts, possibly suggesting that P. tricuspis is more responsive than P. curvatus to fire ant odorant volatiles. When comparing the EAG responses to three fire ant extracts, both sexes of P. tricuspis and P. curvatus females responded similarly to black and hybrid fire ants, significantly stronger than to red fire ant. This trend may explain why P. curvatus prefers black and hybrid fire ants over red fire ant. Further study may be needed to determine whether P. tricuspis prefers, in the same way as P. curvatus, black and hybrid over red, or vice versa.


Species 1: Diptera Phoridae Pseudacteon tricuspis (phorid fly)
Species 2: Hymenoptera Formicidae Solenopsis invicta (red imported fire ant, fire ant)
Species 3: Hymenoptera Formicidae Solenopsis richteri (black imported fire ant)