Do cattle wormers have a long-term impact on non-target insect fauna?
Olwen Williams Open University Abstract In the course of a part-time PhD, I have attempted to investigate in the field the effects of three different approaches to cattle worming, comparing a spring bolus of Oxfendazole and a spring pour-on dose of Ivermectin with an organic ‘no treatment’ regime. Besides doing field counts of Scatophaga stercoraria (yellow dung flies), I have measured the hatching yield of Diptera, using emergence trapping, and the extracted yield of both Diptera and Coleoptera from dung pats. Preliminary results indicate that both treatment regimes have adverse effects on dung-dependent insect fauna, though the timing of this varies. However, even at times when the dung is inhospitable for development, the number of adult S. stercoraria present in the field does not vary with the treatment regime. This suggests that some dung-dependent insects may be sufficiently mobile to colonise fresh dung several kilometres away and raises the question whether treated dung may be
