Regular distribution of larvae and resource monopolization in the seed beetle Bruchidius dorsalis infesting seeds of the Japanese honey locust Gleditsia japonica

摘要: Larvae of the wild multivoltine bruchid seed beetle Bruchidius dorsalis infest dry mature seeds Japanese honey locust Gleditsia japonica. The frequency distribution B. larvae per was examined in laboratory. First, preliminary observation showed that first-instar larva crawled from an eggshell and traveled excess 25 cm before boring into a seed. prefer noninfested rather than infested (indicated by previous emergence hole). When occasionally bored previously seed, it could emerge as adult spite decreased body weight. Second, we conducted experiment 1 to investigate distributions number holes seed; results significantly regular (a smaller variance Poisson) which most had been one larva. Third, performed 2 examine relationship between initial emerged adults their weight given increased ratio egg density abundance experimental manipulation, multiple (up ten) bore However, only each about 85% with borings. emerged, constant, independent Two large difference sizes. Even this case, larger heavy single emergence, although other (about 60%) normal size. These show severe contest-type competition among within winner often monopolizes almost all resources even though part resource still remains.