Invasive ant species have general diet and nest requirements, which facilitate their establishment in novel habitats and their dominance over many native ants. The Asian needle ant, Pachycondyla chinensis, native throughout Australasia was introduced to the southeastern US where it has become established in woodland habitats, nests in close proximity to and consumes subterranean termites (Rhinotermitidae). P. chinensis do not occur in habitats lacking Rhinotermitidae. We suggest that subterranean termites are critical for P. chinensis success in new habitats. We demonstrate that P. chinensis is a general termite feeder, retrieving Reticulitermes virginicus five times more often than other potential prey near P. chinensis colonies. Odors produced by R. virginicus workers, as well as other potential prey, attract P. chinensis. Furthermore, P. chinensis occupy R. virginicus nests in the lab and field and display behaviors that facilitate capture of R. virginicus workers and soldiers. Termites are an abundant, high quality, renewable food supply, in many ways similar to the hemipteran honeydew exploited by most other invasive ant species. We conclude that the behavior of P. chinensis in the presence of termites increases their competitive abilities in natural areas where they have been introduced.

Studies of species coexistence in ant communities often suggest that competitive interactions are mediated by behavioral trade-offs between resource discovery and dominance. However, these studies have always measured foraging at artificial, static baits that omit traits of living prey items and potential coevolutionary predator-prey relationships. In a series of lab experiments, we compare the ability of ants to harvest live termites (Reticulitermes virginicus) in nests varying in defensive ability. Moreover, we compare foraging performance of 2 co-occurring ant species-the North American native Aphaenogaster rudis and the invasive Pachycondyla chinensis-differing in their evolutionary experience hunting R. virginicus. Our results show how the invasive P. chinensis may displace the native keystone A. rudis by directly killing A. rudis workers and reducing termite prey available for A. rudis. Specifically, P. chinensis is more sensitive to novel termite prey than the native A. rudis and then destroys termite colonies-even if they are highly defended by soldiers or nest architecture. Our results further show how whole colony behavioral dominance by P. chinensis is mediated by behavioral interactions among individual workers. More generally, our experimental approach using live prey to study interspecific competition can integrate evolutionary dynamics into studies of proximate behavioral factors governing species coexistence.

Groundwater dye tracing has proven to be an effective tool for aquifer characterization, protection, and to provide remediation strategies in karst areas. Tracing groundwater flow routes with fluorescent dyes is highly successful because they are water soluble and inexpensive. Fluorescent dyes are usually the best tracers to use in karst because they are easily detected in concentrations that are one to three orders of magnitude less than those at which nonfluorescent dyes can be measured spectrometrically. Additionally, they are safe to use, work effectively in different hydrogeologic settings, and can be used effectively to trace water from subsurface to surface water bodies. Dye tracing in karst has been used successfully to (1) delineate spring recharge areas and subsurface basins, (2) determine site‐specific hydrology, (3) estimate groundwater flow velocities, (4) trace groundwater flow from areas of recharge to discharge, (5) delineate wellhead protection areas, (6) map and characterize conduit flow routes, (7) detect leakage from residential sewage disposal systems, (8) identify sources of potential pollution from hazardous waste sites, (9) detect leakage from dam sites, and (10) characterize groundwater flow routes to important springs and cave streams along highway corridors.

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The most interesting aspect of a karst landscape is its unique hydrologic system. Karst landscapes are primarily underlain by carbonate, primarily limestone and dolomite, where surface water and groundwater are interconnected to form one functional unit. The end result of this hydrologically integrated flow system is the karst spring. Springs provide substantial quantities of water for human consumption and commercial enterprises. Because karst aquifers provide effective natural cleansing, it is imperative to understand the dynamic flow systems within these aquifers to protect these vulnerable water supplies from contamination.