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Correspondence: Noboru Kudo

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Noboru Kudo
Takshi Oyamada
Masami Okutsu
Masatake Kinoshita
Department of Veterinary Parasitology, School of veterinary Medicine and animal Sciences, Kitasato University, Towada, Aomori 034, Japan.

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Abstract
Between July 1987 and august 1988, a total of 16,422 dung beetles belonging to 13 species of 5 genera were collected from pastures in Rokkasho and Towada, Aomori Prefecture, Japan and examined for 3rd-stage larvae of Gongylonema pulchrum. G. pulchrum larvae were found in 11 species of the beetles: Aphodius rectus, A. sordidus, A. elegans, A. harodianus, A. urostigma, A. sublimbatus, Liatogus phanaeoides, Caccobius jessoensis, Onthophagus bivertex minokuchianus, Copris ochus, and C. acutidens. Larvae were not recovered from A. pusillus or O. lenzii. The highest density of larvae (highest mean number of larvae recovered per individual in the various species) was 3.788 in C. ochus, and followed by 0.523 in A. rectus, 0.223 in A. sordidus, 0.003 in A. jessoensis. The prevalence of infection was the highest in C. sordidus, 0.167 in A. haroldianus, and 0.130 in A. elegans. The lowest density was 0.003 in C. jessoensis. The prevalence of infection was the highest in C. ochus (48.3 % infected) and A. rectus is most likely to be eaten by the definitive hosts (cattle), so this beetle was the most important intermediate host in the study area. The infection rate, as estimate by repeated examination of groups of 10 individuals of A. rectus, increased in autumn and was close to the high level reached in the following spring. According, most of the larvae in the hibernating beetles seemed to have survived. When live infected A. rectus were put into water left there live larvae were found in the water between day 4 and 34. Definitive hosts ,may be infected by drinking water contaminated with G. pulchrum larvae. This report is the first in our knowledge on intermediate of G. pulchrum.

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Key words: dung beetles; Gongylonema pulchrum; intermediate host; survey; Japan.

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