The short-term effects of two chaining treatments on populations of Tabanus abactor Philip (Diptera: Tabanidae)

Abstract

The effect of chaining of rangeland on populations of Tabanus abactor Philip was evaluated on two ranches in the Texas Rolling Plains. Two chaining treatments were applied to the study area: standard surface level chaining, and roller-ball chaining with an elevated striking height of 0.6 m. Larvae were sampled by digging and searching uniform areas of soil t the base of redberry juniper trees, where the larvae are found. Soil was also sampled for moisture content in May 1998. Brown boards on the ground and white buckets in the air, both coated with Tanglefoot@ stickun-4 were used to capture adult flies and monitor their activity. Brown boards capture mostly male flies, and white buckets capture female flies almost exclusively. Chaining did not significantly affect populations of larvae within one season, or have an effect on soil moisture. In plats receiving the standard chaining treatment, 65% less flies were captured on bucket traps than in the controls. Roller-ball chaining did not significantly reduce the number of flies captured on bucket traps. Neither treatment reduced the number of flies captured on board traps. Seasonal patterns of fly activity, and fly activity in relation to rainfall were recorded and are presented. Fly activity was also evaluated against tree density. The numbers of flies present in the study plots did not change as canopy cover increased from 20% to 55%.