The role of anthropogenic disturbance and invasion of yellow crazy ant in a recent decline of land crab population

Anthropogenic Influence on the Distribution of the Longlegged Ant (Hymenoptera: Formicidae)

The longlegged ant Anoplolepis gracilipes (Smith) is a highly invasive tramp ant species known for its deleterious effects on native ecosystems. While tramp ants are associated with human activity, information on how different intensities of human activity affect their distribution is limited. This study investigated how anthropogenic activities affected the distribution of A. gracilipes in Penang, a tropical island in northern peninsular Malaysia. Three study sites (Youth Park, Sungai Ara, and Bukit Jambul/Relau) were selected, containing four sub-locations corresponding to different levels of human activity (low, moderate, high, and very high), determined by the average number of passersby observed over 30 min. Baited index cards were placed at each sub-location to evaluate ant abundance and distribution. The results demonstrated that A. gracilipes worker abundance was highest in areas of moderate human activity, as opposed to areas with low and higher human activity. The low abundance of A. gracilipes in comparatively undisturbed localities may be attributed to unsuitable microclimate, lack of propagule pressure, and diminished honeydew availability. In contrast, its exclusion from more urbanized localities could be explained by high interspecific competition with other tramp species and the absence of preferred nesting sites.

Biology, Ecology, and Management of the Invasive Longlegged Ant, Anoplolepis gracilipes

The longlegged ant (Anoplolepis gracilipes) is one of the most damaging invasive tramp ants globally. It is generally found between latitudes 27°N and 27°S in Asia, although it has been introduced to other continents. Its native range remains debatable, but it is believed to be in Southeast Asia. Anoplolepis gracilipes invasion has many serious ecological consequences, especially for native invertebrate, vertebrate, and plant communities, altering ecosystem dynamics and functions. We examine and synthesize the literature about this species' origin and distribution, impacts on biodiversity and ecosystems, biology and ecology, chemical control, and potential biocontrol agents. We highlight emerging research needs on the origin and invasion history of this species, its reproductive mode, its relationship with myrmecophiles, and its host-microbial interactions, and we discuss future research directions.