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Title: Effects of an Insect Growth Regulating Bait on the Tawny Crazy Ant, Nylanderia fulva

Author
item Oi, David

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 7/7/2014
Publication Date: 10/13/2014
Citation: Oi, D.H. 2014. Effects of an Insect Growth Regulating Bait on the Tawny Crazy Ant, Nylanderia fulva. Meeting Abstract. pp. 11-12.

Interpretive Summary: The tawny crazy ant, Nylanderia fulva, which previously has been called the Caribbean crazy ant and the Rasberry [sic] crazy ant, is an invasive ant that continues to spread in the southern U.S. Scientists at Center for Medical Agricultural and Veterinary Entomology in Gainesville, Florida have been tracking its distribution and developing control strategies for this burgeoning pest. Over the past year (March 2013-April 2014), new infestations have been reported from 8 new counties or parishes in Texas, Louisiana, and Florida, plus Georgia reported its first infestation. There are now a total of 63 counties or parishes with reports of tawny crazy ant infestations in the U.S. Potential strategies to control this invasive ant include the use of insect growth regulating (IGR) baits. IGR baits would be ideal for controlling tawny crazy ants that nest in inaccessible habitats but can forage on baits applied to managed landscapes or around buildings. Commercially available IGR ant baits (typically fire ant baits) are not foraged upon by tawny crazy ants, thus a food lure accepted by this species was formulated in the laboratory with either of two IGRs, (S)-methoprene or pyriproxyfen. In laboratory tests with tawny crazy ant colonies that each contained 40 queens, thousands of adult worker ants, and immature ants, there was a significant reduction in immature ants (62-92% for methoprene and 89-95% for pyriproxyfen). Production of immature ants is critical for the survival of ant colonies, and it is the stage affected by IGRs. In addition, queens from IGR treated colonies had less eggs in their ovaries. However, repellency was observed with the IGR baits, where both IGR baits were consumed less than bait without IGRs. Nevertheless, IGR baits do cause substantial declines in the production of immature tawny crazy ants and warrants further IGR bait development.

Technical Abstract: The tawny crazy ant, Nylanderia fulva, which previously has been called the Caribbean crazy ant and the Rasberry [sic] crazy ant, is an invasive ant that continues to spread in the southern U.S. Over the past year (March 2013-April 2014), new infestations have been reported from 3 counties in Texas, 4 parishes in Louisiana, 1 county in Florida, and the first report of an infestation in Georgia. There are now a total of 63 counties or parishes with reports of tawny crazy ant infestations in the U.S. Potential strategies to control this invasive ant include the use of insect growth regulating (IGR) baits. IGR baits would be ideal for controlling tawny crazy ants that nest in inaccessible habitats but can forage on baits applied to managed landscapes or around structures. Commercially available IGR ant baits (typically fire ant baits) are not foraged upon by tawny crazy ants, thus a food lure accepted by this species was formulated in the laboratory with either of two IGRs, (S)-methoprene or pyriproxyfen. In laboratory tests with whole colonies that each contained 40 queens and 2000-4500 worker ants, and 2-6 ml of brood, there was a significant reduction in brood (62-92% for methoprene and 89-95% for pyriproxyfen), which is the stage affected by IGRs. In addition, queens from IGR treated colonies had less eggs in their ovaries. However, repellency was observed with the IGR baits, where both IGR baits were consumed less than the blank food lure. Nevertheless, IGR baits cause substantial declines in brood production in tawny crazy ants and further IGR bait development is warranted.