Effects of moxidectin on coprophagous insects in cattle dung pats in Japan

Abstract

Effects of the antiparasitic drug moxidectin were studied in laboratory and field experiments in Hokkaido, Japan by pour-on administrations (500 mg/kg) on a target pest Haematobia irritans Linnaeus, nontarget coprophagous flies represented by Neomyia cornicina (Fabricius), and the dung beetle Caccobius jessoensis Harold. The concentration of moxidectin excreted into cattle dung was maximum at 3 days post-treatment both in the first and second trials, and then it diminished. No moxidectin was detected on or after day 21 post-treatment in the first trial, and on or after day 28 post-treatment in the second trial. Larval development of H. irritans was hampered from 1 to 7 days post-treatment. No N. cornicina pupated in dung at days 1 and 3 post-treatment, and pupation and emergence rates were reduced in the dung until 7 days post-treatment. There were no significant differences in numbers and weight of brood balls constructed by Caccobius jessoensis in dung from treated and control cattle. Adult emergence rates of C. jessoensis on days 1, 3, 7, 14 post-treatments were not significantly different between control and treated groups, and more than 90% of adult emergence rates were demonstrated in both groups. In the field study using emergence traps, 3,433 (18 families) flies emerged from dung from untreated control cattle and 1,667 (16 families) flies emerged from dung from treated cattle. Notably, the number of Sciaridae spp. (first Experiment) and Sepsis latiforceps Duda and Sphaeroceridae spp. (second Experiment) significantly decreased in dung pats of treated cattle. From 48 dung pats in the field experiments, total dry weight of major coprophagous flies that emerged was 1,741.8 mg in dung from control cattle and 1,170.0 mg in dung from treated cattle, showing 32.8% reduction in treated dung. Emergence rates of C. jessoensis from brood balls recovered from soil beneath dung pats in the field experiments were not significantly different between dung from control and treated cattle on each sampling day (1, 7, 14, and 21 days) post-treatment.

Effects of the veterinary antiparasitic drug eprinomectin on dung beetles (Coleoptera: Scarabaeidae), the non-pest fly Neomyia cornicina and pest fly Haematobia irritans (Diptera: Muscidae) in Japan

“…Cattle were mainly fed with grass hay, grass and dent corn silages, and commercial concentrates in experiment 1, while cattle were mainly fed with green pasture grass in experiment 2. Iwasa et al (2008) showed that the maximum fecal residual level of moxidectin in dung from cattle mainly fed with green pasture grass was lower than that from cattle mainly fed with grass hay, suggesting that the fecal residual level of drug could also be associated with a difference in fecal moisture contents. It is suggested that the low level of maximum residues of eprinomectin in dung in experiment 2 are also due to the green-grass diet, so residue levels are related to moisture contents of dung depending on animal diets.…”

“…The present results are similar, but there was a considerable difference in concentrations at 2 and 3 days post-treatment in the present two experiments. It is known that concentrations of residual ivermectin and moxidectin in the dung of cattle can be affected by their diet (Cook et al 1996;Iwasa et al 2008). The marked difference observed in maximum fecal residual levels of eprinomectin at 3 days post-treatment in experiments 1 and 2 could be attributable to the difference in diets even in our study.…”

“…Collections of eggs and rearings of larvae were performed by following the method of Iwasa et al (2008). Rearing experiments were replicated five times for each dung collection date from control and treated cattle in experiment 2.…”

“…This species is also sensitive to antiparaticicides, and collecting eggs and rearing larvae are very easy. Collections of eggs and rearings of larvae also followed the method of Iwasa et al (2008). Rearing experiments were replicated five times for each collection date after treatment in experiment 2.…”

How to test nontarget effects of veterinary pharmaceutical residues in livestock dung in the field

“…Numerous studies have assessed the effects of VMPs on dung organisms, both in the laboratory and in the field, using different methods (reviews by Floate et al 2005;Lumaret and Errouissi 2002;Wardhaugh 2005;also Floate 2007;Floate et al 2008;Hempel et al 2006;Iwasa et al 2007Iwasa et al , 2008Kryger et al 2005Kryger et al , 2007Lumaret et al 2007;Rö mbke et al 2007Rö mbke et al , 2009Suárez et al 2009;Webb et al 2007Webb et al , 2010. Collectively, these studies support the following conclusions: 1) there has been a strong bias for research on endectocides, primarily ivermectin but also doramectin, eprinomectin, and moxidectin; 2) most of the research studies have been performed in Europe, Canada, and Australia, and to a lesser extent in Japan, South Africa, South America, and the United States; 3) the lethal effects of residues on species of dungbreeding flies and beetles in cattle dung are most often measured; 4) because insect activity can accelerate dung pat degradation, the effect of residues on the rate of dung decomposition also is often measured in field-based studies; 5) the lack of standard test methods and reporting protocols largely prevents direct comparisons among studies; and 6) the interpretation of results is generally hampered and easily confounded by a lack of knowledge about the local biological aspects of the study system, i.e., the dung pat and its associated organisms, which may vary considerably among geographic regions.…”