Mating, oviposition, and prey use by larvae of Hypsopygia postflava (Lepidoptera: Pyralidae), a moth parasitic on nests of the paper wasp, Polistes jokahamae.

室内実験によって, セグロアシナガバチ Polistes jokahamae の巣に寄生するウスムラサキシマメイガ Hypsopygia postflava の交尾習性と産卵特性, 幼虫の寄主利用の行動を明らかにした. 成虫はおもに23:00〜6:00の間に交尾を開始し, 平均交尾継続時間は80.4分であった. 交尾後のメス成虫は, ハチ成虫を除去した巣ではおもにハチの繭上にまたは数卵ずつ産卵した. しかし, ハチ成虫が在巣する場合は, ハチの攻撃を受け, ほとんどの個体が巣内へ侵入することができず, 巣柄近辺に1個ずつあるいは数十卵からなる卵塊を産卵した. メス成虫の寿命は平均10.7 日で, その間に平均133.9卵を産んだ. また, メイガの1齢幼虫をハチ成虫がいる巣の巣柄から10cmの距離に数詞したところ, 55%の個体が巣内へ到達した. 巣内へ侵入した1齢幼虫は, ハチの蛹の捕食を開始した. 蛹を食べて発育した後ハチの幼虫を捕食した.We investigated the mating, oviposition, and prey use by larvae of Hypsopygia postflava, a moth that is parasitic on nests of the paper wasp, Polistes jokahamae, in the laboratory under natural temperature, humidity, and day-length conditions, and in field cages. Mating occurred mainly from 2300 to 0600 hours, and copulation lasted a mean of 80.4min. When adult wasps were absent from the nest, female adults of the moth laid eggs singly or in clumps of a few eggs, mainly on the walls of cells containing cocoons with live pupae or pupal exuviae. When adult wasps were present on the nest, wasp attacks prevented female moths from approaching the nest, and so they laid eggs singly or in clumps of several tens around the base of the nest pedicel. Female moths laid a mean of 133.9 eggs during their mean lifetime of 10.7 days. When first-instar larvae were released 10 cm from the base of the nest pedicel, 55% of them arrived in the nest with adult wasps. Moth larvae fed on wasp pupae first, and then on wasp larvae