|RASHID, TAHIR - Alcorn State University|
|GUOLEI, FENG - Alcorn State University|
|LIMING, ZHAO - Animal And Plant Health Inspection Service (APHIS)|
|DREES, BASTIAAN - Texas A&M University|
Submitted to: Toxicon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/19/2013
Publication Date: 9/27/2013
Citation: Chen, J., Rashid, T., Guolei, F., Liming, Z., Oi, D.H., Bastiaan Drees 2013. Defensive chemicals of tawny crazy ants, Nylanderia fulva and their toxicity to red imported fire ants (Hymenoptera: Formicidae). Toxicon. 76:160-166.
Interpretive Summary: The red imported fire ant is a well-known pest ant species with significant ecological and economic impact. Nylanderia fulva is the only ant species that has been reported as being able to displace the red imported fire ants in the field. Defensive secretion often plays an important role in determining the outcome of competition among ants. Study on the chemistry of defensive secretion in N. fulva may help us identify new fire ant toxins which are potentially useful in managing fire ants. In this study, we found formic acid, 2-tridecanone and undecane are major defensive chemicals in Nylanderia fulva. Both 2-tridecanone and formic acid have significant toxicity against the red imported fire ants.
Technical Abstract: Nylanderia fulva (Mayr) has been reported as being able to displace Solenopsis invicta Buren, one of the most aggressive invasive ants in the world. Like S. invicta, N. fulva use chemical secretions in their defense/offense, which may contribute to their observed superior competition ability. In this study, the defensive chemicals of N. fulva workers and their toxicity against S. invicta workers were investigated. Like other formicine ants, N. fulva workers produce formic acid in their poison glands and 2-ketones and alkanes in Dufour glands. Of these, undecane and 2-tridecanone are two principal compounds in the Dufour gland. Topical LD50 values of 2-tridecanone and undecane against S. invicta workers ranged from 18.51 to 24.67 µg/ant and 40.39 to 84.82 µg/ant, respectively. Undecane and 2-tridecanone had significantly higher contact toxicity than formic acid, whereas formic acid had significantly higher fumigation toxicity than undecane and 2-tridecanone. The combination of 2-tridecanone as a contact toxin and formic acid as a fumigant significantly decreased KT50 values when compared to those of individual compounds. Nylanderia fulva does not seem unique in terms of the chemistry of its defensive secretion as compared to other formicine ants. However, this ant contained more than two orders of magnitude of formic acid (wt/wt) than other formicine ants and one order of magnitude of 2-tridecanone than the common crazy ant, Paratrechina longicornis (Latreille). The quantity, rather than quality, of the chemical secretion may contribute to the superior competition ability of N. fulva.