Effects of ivermectin residues in sheep dung on the development and survival of the Musca vetustissima Walker and a scarabaeine dung beetle, Euoniticellus fulvus Goeze

• Published in: Veterinary Parasitology. 1993
• Main Authors: Wardhaugh, K G, Mahon, R J, Axelsen, A, Rowland, M W, Wanjura, W, Herd, R, Wardhaugh, K
• Format: Conference Proceeding
• Language: English
• Published: 01.01.1993
• Subjects: Coleoptera; Diptera; Muscidae; Scarabaeidae
• ISSN: 0304-4017

Dung produced by sheep for up to 1 week post-treatment (drenching) with ivermectin caused significant mortality to newly emerged larvae of the bushfly Musca vetustissima. Dung from sheep drenched with a mixture of levamisole and oxfendazole also resulted in larval mortality, but here the effect was limited to the first 48 h after treatment. Flies reared through to the adult stage on dung collected up to 32 days post-drenching were tested for evidence of fluctuating asymmetry, which is an indicator of developmental stress. None was found for either drench treatment, although there was evidence that ivermectin residues directly affected wing size. The introduced dung beetle, Euoniticellus fulvus was also found to be sensitive to ivermectin residues in sheep dung. Dung produced during the first day after drenching caused mortality among newly emerged beetles and delayed the reproductive development of survivors. The findings indicate that insects feeding on the dung of ivermectin-treated sheep display adverse effects similar in range to those reported for cattle dung. However, their duration is much more transient, owing probably to differences in drug formulation and route of administration.