Behavior and activity patterns of the black scavenger fly, Sepsis punctum (Diptera: Sepsidae), near a permanent dung source

Abstract

The behavior of the black scavenger fly Sepsis punctum (L.) (Diptera: Sepsidae) was studied on satellite resource (dung) patches established near a pig pen. Flies were most numerous on the patches when ambient temperature and light conditions were high. Females were commonly found on the patches and males occupied boards surrounding the patches where they displayed vigorously to other males and females. Approximately four times as many females as males occurred on the patches. Females were larger than males, and paired males were larger than unpaired males. Males did not exhibit precopulatory guarding as reported in Sepsis cynipsea (L.) and European populations of S. punctum, and copulatory encounters appeared to be brief. The permanency of pig dung utilized by this population of S. punctum compared to the transience of cow pats utilized by S. cynipsea may influence differences in sex ratios, precopulatory guarding, copulation duration, and male aggressive behavior in the two species.