Location: Biological Control of Pests ResearchTitle: Antimicrobial properties of nest volatiles in red imported fire ants, Solenopsis invicta (Hymenoptera: Formicidae) Author
Submitted to: Naturwissenschaften
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2015
Publication Date: 12/1/2015
Publication URL: http://handle.nal.usda.gov/10113/61869
Citation: Wang, L., Elliott, R.B., Jin, X., Zeng, L., Chen, J. 2015. Antimicrobial properties of nest volatiles in red imported fire ants, Solenopsis invicta (Hymenoptera: Formicidae). Naturwissenschaften. 102:66. Interpretive Summary: Due to its threat to public health, agriculture, and wildlife, red imported fire ant is a global significant pest. Tremendous effort has been made in developing sustainable fire ant control strategies, including biological control using pathogenic microorganisms. Ants have developed multiple layers of defense against their natural enemies. It is crucial to understand their defense mechanisms before we can successfully implement any biological control practices. In this study, we found the antimicrobial property of nest volatiles produced by red imported fire ants. The spore germination rate of Beauveria bassiana, a common entomopathogenic fungus, was significantly inhibited after they were exposed to nest volatiles of red imported fire ants, indicating that nest fumigation may be an important component of the social immune system in fire ants. How to overcome such unique chemical defense may be a key to the success of any fire ant biological control using pathogenic microorganisms. This study may have significant impact in the research of pest insect biological control, particularly nest building pest social insects.
Technical Abstract: In social insects, antimicrobial secretions are often used collectively for the benefit of the whole colony, which is an important component in social immunity. Many ant species build nests in which air circulation can be controlled. Volatile antimicrobial agents would be ideal in implementing social immunity for insects with a relatively closed nest system, because volatiles can readily reach pathogens in a nest even before pathogens contact their host. Vapor phase antimicrobial property of several compounds in termite gland secretions have been demonstrated individually, but at rather arbitrary concentrations. Antimicrobial properties of nest volatiles have never been demonstrated for any ant species. Here we report antimicrobial property of nest volatiles produced by red imported fire ants, Solenopsis invicta Buren, against Beauveria bassiana, a common entomopathogenic fungus. The germination rate of B. bassiana spores were significantly reduced after they were exposed to nest volatiles within an artificial ant nest. Since the air that contained the same level of O2 and CO2 as that in artificial fire ant nests did not suppress the germination rate of B. bassiana, the observed reduction of germination rate under fire ant nest volatiles was not due to the change of O2 and CO2 concentrations in the nest caused by ant's respiration, but the toxicity of nest volatiles. Nest fumigation may be an important component of the social immune system in S. invicta.