Date of Graduation

12-2014

Document Type

Thesis

Degree Name

Master of Science in Entomology (MS)

Degree Level

Graduate

Department

Entomology

Advisor/Mentor

Loftin, Kelly M.

Committee Member

Stephen, Frederick M.

Second Committee Member

Porter, Sanford D.

Keywords

Biological Control

Abstract

Red imported fire ants are major pests in the southeastern United States. As a part of an integrated pest management strategy, a biological control program has been implemented which includes Pseudacteon decapitating flies. These flies are parasitoids of fire ant workers and two species of Pseudacteon are established in Arkansas: Pseudacteon tricuspis and Pseudacteon curvatus. Pseudacteon cultellatus and P. obtusus were released in the spring and fall of 2013. Despite sampling throughout 2014, establishment cannot be confirmed. Two phorid fly sampling methods, hand aspirating and sticky traps, were studied. A vacuum aspirator was compared with two sticky trap configurations. Sticky traps used one of three bait types: live fire ants, dead fire ants, and foraging fire ants. Both P. curvatus and P. tricuspis were captured, but many more P. curvatus were caught than P. tricuspis. Foraging fire ant-baited traps caught relatively few flies. In contrast, live ant and dead ant-baited traps captured many flies, with dead ant-baited traps performing better overall. A lab study was performed to investigate possible competition among flies that were released in Arkansas because P. curvatus has been reported to competitively displace P. tricuspis in other states. Pseudacteon curvatus was paired with P. obtusus and P. cultellatus in parasitization trials. Host size, sex ratios, species ratios, and development times were recorded to evaluate possible competitive interactions between species. Due to a shortage of P. cultellatus at the Florida Department of Agriculture rearing lab, this species was not analyzed. Pseudacteon curvatus host sizes did not vary by sex but P. obtusus hosts were smaller for males than for P. obtusus females. Sex ratios varied between species, but competition treatments did not influence sex ratios or rates of parasitism.

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