Author
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Wojcik, Daniel |
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Brenner, Richard |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 4/6/1998 Publication Date: N/A Citation: N/A Interpretive Summary: Fire ants occur in 11 southern states, and cause hundreds of millions of dollars of damage to domestic animals, wildlife, and the infrastructure (roads, electrical systems, equipment, etc), in addition to their impact on humans health each year. Researchers at the ARS Center for Medical, Agricultural and Veterinary Entomology in Gainesville, FL assessed impact of the foraging behavior of imported fire ants on endangered cave invertebrates, using cave crickets and fish-bait crickets as surrogates for the endangered species. Comparison of the foraging patterns of fire ants and cave crickets using attractant food baits and monitoring over a one hour period after dark, in combination with spatial statistical analysis, demonstrated that fire ants and cave crickets foraged intensively in and around the caves in Texas. Cave crickets and fish-bait crickets were used as surrogates, to assess susceptibility of endangered cave species to impact by fire ant management practices and chemicals. First, crickets were fed on specific numbers of bait granules to determine the risk Amdro bait poses to the crickets. Amdro granules were toxic to cave crickets and fish-bait crickets feeding on bait granules. Second, crickets were fed on Amdro poisoned fire ant cadavers, to determine if the movement of toxicants via scavengers into the cave systems was possible. Amdro poisoned fire ant cadavers did not pose a threat to the cave crickets. The ants could easily be controlled without affecting the cave crickets by restricting fire ant treatments to morning hours, thus allowing sufficient time for the fire ants to forage and retrieve all of the bait particles before the cave crickets emerge from the caves during the night. Technical Abstract: Field studies using attractant non-toxic baits demonstrated that fire ants foraged intensively in and around the caves in Texas. These studies also demonstrated that cave crickets foraged widely around the caves after dark. The objectives were to assess susceptibility of endangered cave species to impact by fire ant and fire ant management practices and chemicals. As it was not feasible or legal to test endangered cave species, cave crickets, scavenger species important in the cave food chain were used as a surrogate. The cave crickets live and reproduce in the caves and forage for food outside of the caves. Cave crickets were tested in two ways. Cave crickets were fed on specific numbers of bait granules to determine the risk Amdro bait poses to the crickets. Cave crickets were fed on Amdro poisoned fire ant cadavers, to determine if the movement of toxicants via scavengers into the cave systems was possible. Additional tests were conducted using fish-bait crickets as surrogates for cave crickets. Amdro granules were toxic to cave crickets and fish-bait crickets feeding on bait granules. Amdro poisoned fire ant cadavers did not pose a threat to the cave crickets. The ants could easily be controlled without affecting the cave crickets by restricting fire ant treatments to morning hours, thus allowing sufficient time for the fire ants to forage for and retrieve all of the bait particles before the cave crickets emerge from the caves during the night. |
