We investigated the effects of the antiparasitic drug ivermectin on the dung beetles Copris acutidens Motschulsky, Onthophagus bivertex Heyden, O. lenzii Harold and Phelotrupes auratus auratus Motschulsky in Japan. Ivermectin was detected in cattle dung from 1 to 3 or 7 days post-treatment, with a peak at 3 days post-treatment in two pour-on administrations (500 µg kg−1). In C. acutidens, adult survivals and numbers of brood balls were significantly reduced in dung collected at 3 and 7 days post-treatment, and adult emergence rates were significantly decreased in dung collected at 7 and 14 days post-treatment. Feeding activity of C. acutidens was inhibited in dung collected at 3 days post-treatment, but was not significantly different from that seen in control dung at 7 and 14 days post-treatment. In O. bivertex and O. lenzii, there were no effects of ivermectin on adult survival or feeding activities, but the numbers of brood balls of O. bivertex constructed in dung collected at 3 and 7 days post-treatment were significantly lower than observed with control dung. The adult emergence rates of O. bivertex and O. lenzii were significantly reduced in dung collected at 1 to 3 and 1 to 7 days post-treatment, respectively. In P. auratus, there were no effects of ivermectin on adult survival, oviposition, feeding activity, or larval survival (until the third instar) in dung at 3 days post-treatment. The environmental risks affecting the populations of dung beetles in Japan are discussed.
Effects of the antiparasitic drug eprinomectin were studied on the dung beetles, Onthophagus lenzii Harold and the rare species, Copris ochus Motschulsky by pour-on administrations (500 µg kg-1) in Japan. Eprinomectin was detected in cattle dung from 1 to 7 or 14 days after treatment, with a peak at 1 day after treatment in two experiments. In O. lenzii, adult survivals and numbers of brood balls constructed were significantly reduced in dung from eprinomectin-treated cattle at 1 and 3 days post-treatment in experiment 1, and adult emergence rates were extremely reduced in dung at 1, 3, and 7 days post-treatment. In C. ochus, adult survivals were significantly reduced in dung at 3 days post-treatment (experiment 1), and equivalent levels to the control were restored in dung at 7 and 14 days post-treatment (experiment 2). Numbers of brood balls of C. ochus were nil in dung at 3 days (experiment 1), and significantly reduced in dung at 7 days (experiment 2) post-treatment compared with control. Adult emergence rates of C. ochus were 100 and 71.6% in dung from control cattle in experiments 1 and 2, respectively. However, no oviposition was observed in dung at 3 days post-treatment, and all offspring died at egg or the first instar larval stage in dung from 7 and 14 days post-treatment. Feeding activities of O. lenzii and C. ochus were significantly inhibited in dung from treated cattle at 1-3 days and 3 days post-treatment, respectively, returning to levels of the control at 7 days post-treatment.
An entomophthoraceous fungus, Neozygites sp. attacked the Kanzawa spider mite, Tetranychus kanzawai (Kishida) in a tea field, Hidaka, Saitama Prefecture, Japan. The fungal infections with Neozygites sp. in a population of T. kanzawai occurred in May, June, September and October but did not occur in July and August. The percentage parasitism of spider mites by Neozygites sp. for larvae, nymphs and adults were 0%, 5.5% and 29.6%, respectively in September. Resting spores were azygospores and were found in cadavers of T. kanzawai collected from September to November. Resting spores on the tea leaves germinated from early to late May in a tea field. Resting spores germinated with short germ tube to form a spherical primary germ conidium remaining on germ tube and forming a capilliconidium.
An epizootic of entomophthoraceous fungus, Zoophthora radicans in a population of Empoasca onukii in a tea field,Iruma, Japan, are described. The occurrence of the epizootic was monitored 1 or 2 times in a month, from September to October in 1980 and from April to November in 1981,under insecticide control. No fungicides were applied.The cadavers of adults and nymphs of E.onukii by the fungus were observed on the abaxial surface of tea leaves.Infections of the fungus caused up to 40.7% nymphs mortality in late September, 1980 and 36.2% adults and nymphs mortality in late October, 1981.The cadavers developing resting spores were observed with the cadavers developing conidia in late September, 1980 and in late October,1981.This is the first report of Z.radicans infecting E.onukii in Japan.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.