Date of Award

12-2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Forestry and Environmental Conservation

Committee Member

Dr. Patricia Zungoli, Committee Chair

Committee Member

Dr. Peter Adler

Committee Member

Dr. Eric P. Benson

Committee Member

Dr. Patrick Gerard

Abstract

Ants are among the most successful invasive organisms in the world. To curb the spread of invasive ants in non-native environments, their ecological, biological, and behavioral characteristics must be identified. The Asian needle ant, Brachyponera (= Pachycondyla ) chinensis (Emery) is an emerging invasive pest in urban areas and forests in the southeastern United States. However, general basic biological information on B. chinensis and subsequent management options are deficient. This work contributes to the standing biological information on B. chinensis by examining the seasonal life cycle, social nesting habits, and transport behaviors of B. chinensis colonies. To determine the seasonal life cycle of Asian needle ants, nests were collected monthly for ten months from infested locations in South Carolina. During the study 40 nests were collected and the number of workers, queens, male/female alates, eggs, larvae, and pupae was determined. The ants follow a seasonal cycle of production. Worker ant numbers are highest in May, August, and October while the majority of male and female reproductives are produced in July and August. Colonies also produce more males than reproductive females during the year. The number of workers and male ants found in a nest is positively correlated with the number of queens. To determine if Asian needle ants are polydomous, I investigated the spatial organization and aggression between B. chinensis nests. Spatial distribution of nests was determined in four B. chinensis infested locations. Monte Carlo tests for compete spatial randomness revealed that three nests followed a pattern of uniform distribution suggesting that the ants are not polydomous. However, nests in one of the plots did follow a clumped distribution. Furthermore, workers originating from the same experimental plot and separate locations did not display aggression in 3 x 3 nestmate recognition assays, suggesting that B. chinensis are a polydomous ant species In a laboratory study, the recruitment behaviors of B. chinensis ants during nest emigration were determined. Before recruitment to the new nest location began, B. chinensisants organized into three distinctive groups: queen-tending, brood-tending, and scouting. Once the new nest site was identified, scout ants began physically transporting nestmates into the new harborage via tandem carrying or adult transport. Transport rates increased in the first 30 minutes and did not change during the 30-55-minute time interval when brood was transported. However, the adult transport rate increased again after brood transport was completed and decreased after 90 minutes. Results presented in the current study contribute to the growing body of biological knowledge on invasive B. chinensis populations in the U.S. The information presented here are the first to address the colony attributes of this species. I identified adult transport as a recruiting method during emigration. Further the information presented here, highlight the life cycle and polydomous nature of B. chinensis and support the development of a seasonally based and area-wide management strategies for this nuisance ant species.

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