PARENT SESSION
Oral Session #86: Invasive species: Ants and other invertebrates.
Presiding: J. Morrison
Thursday, August 8. 1:00 PM to 3:45 PM. Greenlee Meeting Room, TCC.
Red imported fire ant impacts on Northern Bobwhites.
Myers, P. Evans*,1, Allen, Craig1, Horton, P. Mac2, 1 South Carolina Cooperative Research Unit, Clemson University, Clemson, SC2 Clemson Agriculture and Natural Resources Extension, Clemson University, Clemson, SC
ABSTRACT- Range-wide population declines in the northern bobwhite (Colinus virginianus) have been well documented. However, identifying the causes for this decline remains elusive. The decline is attributed primarily to changing land uses, but this cannot explain the decline on areas specifically managed for bobwhites. Earlier studies suggest that red imported fire ants (Solenopsis invicta) may be another factor in the decline of the bobwhite. Therefore, we instituted a large-scale manipulative field study to investigate fire ant impacts on bobwhite and their insect food resources. We reduced fire ant populations on six 100-ha sites in South Carolina with aerial applications of Amdro. We estimated bobwhite densities using line transects, and fire ant and insect abundance with baits and pitfalls. Data was collected prior to and after treatments, and six additional sites served as controls. Because fire ants displace the native ants that serve as an important component of bobwhite chick diets, a laboratory experiment tested if fire ants served as a replacement food in bobwhite diets. Thirty chicks were maintained and fed commercial feed, while 30 more constituted a treatment group and were also provided with the opportunity to feed upon fire ants. Treatments significantly reduced fire ant abundance (P <0.05). Bobwhite densities did not differ post-treatment. However, small insects, an important protein source for bobwhite chicks and reproducing hens, were more abundant on treated sites following treatments (P <0.10). In the laboratory, bobwhite chicks fed minimally on fire ants, but those chicks had reduced survival (P <0.05) and weight gain (P <0.05). We conclude that fire ants represent a threat to bobwhites and other native species that include insects as an important component of their diet, and that fire ants don't replace the enormous loss of native ants and other small insects that follows fire ant invasion.
KEY WORDS: Invasive Species Impacts, Red Imported Fire Ant, Northern Bobwhite, Insect Abundance