Black carpenter ants in the Ozark Mountains of Arkansas: Relationships with prescribed fire, site and stand variables, and red oak borer

Black carpenter ants, Camponotus pennsylvanicus DeGeer, are nearly ubiquitous in eastern North American forests. These ants are documented as predators of red oak borer, Enaphalodes rufulus Haldeman, a native longhorn beetle that underwent an unprecedented population increase and decline in the oak hickory forests of the Ozark Mountains of Arkansas from the late 1990's to 2005.;My objective was to examine red oak borer emergence holes and site aspects and correlate these forest and tree attributes with presence or absence of black carpenter ants. Historic red oak borer population data, tree REP class and site aspects for 13 separate plots were used. At each site, all red oaks >10 cm DBH were baited for black carpenters ants using a mixture of tuna in oil and honey. Black carpenter ants are more likely to be found on trees with low levels of previous red oak borer infestation versus those trees with previously high levels of infestation. These results may suggest black carpenter ants play a role in controlling red oak borer populations. Distribution of black carpenter ants in red oaks prior to and during the outbreak is unknown. Future investigations should be directed at efforts to understand whether black carpenter ants simply prefer different apparently healthy trees or if, via predation, these ants are acting as agents of red oak borer control.;I also examined how tree species and size, site and stand variables, and management practices influence black carpenter ant abundance. Fire treatment, tree species, and tree size were described for 18 plots. All trees were baited as described above, and black carpenter ant presence/absence was recorded for each tree. Black carpenter ants were more commonly present on oaks than on hickories and appear to prefer large trees over small trees. Time elapsed since a prescribed burn appears to be important in determining black carpenter ant presence, potentially via fire-induced habitat modifications, although further investigation is necessary to either confirm or refute this hypothesis.