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

Abstract

Effects of the antiparasitic drug eprinomectin were studied in the laboratory and field experiments in Hokkaido, Japan, by pour-on administrations (500 lg/kg) on the pest fly Haematobia irritans (Linnaeus), nontarget coprophagous fly Neomyia cornicina (Fabricius), and the dung beetles Caccobius jessoensis Harold and Liatongus minutus (Motschulsky). Eprinomectin excreted into cattle dung was highest at 3 days post-treatment in both experiments, then it declined rapidly at 7 days and was not detected on or after day 14 post-treatment. In laboratory experiments, pupation and emergence rates of H. irritans and N. cornicina were hampered from 1 to 14 days posttreatment. There were no significant differences in the numbers of brood balls constructed by C. jessoensis in dung from treated and control cattle. Adult emergence rates of C. jessoensis were significantly reduced on days 1 and 3 post-treatment in dung from treated cattle. There were no significant differences in the numbers of brood balls constructed by L. minutus in dung from treated and control cattle, but survival rates of larvae were significantly reduced on days 1 and 3 post-treatment. In field experiments, the numbers of brood balls by L. minutus recovered from beneath dung pats were significantly larger in number in dung from treated cattle, suggesting that adult beetles are attracted to dung pats from treated cattle. Survival rates of larvae in these brood balls of L. minutus were significantly reduced 1 day post-treatment in dung pats from treated cattle, and equivalent levels to the control were restored 7 days post-treatment. The results are discussed in relation to the effects of endectocides on nontarget insects in grazing pastures.

Effects of eprinomectin on the survival, reproduction and feeding activity of the dung beetles,Onthophagus lenziiHarold, and rare species,Copris ochusMotschulsky (Coleoptera: Scarabaeidae)

“…In previously published studies eprinomectin pour-on formulation was found to cause dung contamination for 1-29 days post-treatment with a peak at 2 or 3 days post-treatment (Lumaret et al, 2005;Iwasa & Sugitani, 2014). Present results which showed a peak at 1 day post-treatment are different from those of above literatures.…”

“…Moreover, there were no brood balls and/or oviposition of C. acutidens and C. ochus in dung from ivermectin-treated cattle at 1 day after treatment (Iwasa et al, 2007). In dung from eprinomectintreated cattle, there was no effect on the number of brood balls of C. jessoensis and L. minutus (Iwasa & Sugitani, 2014).…”

Eprinomectin from a sustained release formulation adversely affected dung breeding insects

“…Reduced survival has been reported for Onthophagus taurus (Schreber) developing in dung of cattle treated up to 14 d previously with a topical application of eprinomectin [ 29 ]. Adult emergence of Caccobius jessoenisis (Harold) was suppressed in dung of cattle injected with a recommended dose of eprinomectin up to 3 d previously, but not 7 d previously, by which time eprinomectin concentrations declined to approximately 50 ng g -1 wet weight [ 7 ].…”

“…In laboratory studies, survival of Neomyia cornicina (Fabricius) and H . irritans was reduced in dung from cattle treated 12 and 14 d previously with a topical application of eprinomectin [ 7 , 29 , 90]. Reduced survival of N .…”

“…The insecticidal activity of fecal residues can have both beneficial and adverse effects on pasture ecology. Residues can reduce populations of pestiferous flies that breed in dung; i.e., Haematobia irritans (Linnaeus) [ 6 – 7 ] and Musca autumnalis De Geer [ 8 ]. Conversely, residues may reduce populations of benign or beneficial species [ 3 , 6 , 9 ] including predaceous and parasitoid species that feed on eggs and larvae of pest species [ 10 – 12 ] and dung beetles (Hydrophilidae, Ptiliidae, Scarabaeidae) that disrupt the pat creating a less suitable breeding site for pest fly species and freeing the pasture surface for the growth of new vegetation [ 13 ].…”