Minoru Baba

Oviposition habits of a univoltine blackfly, Prosimulium kiotoense (Diptera: Simuliidae), in Kyushu, Japan

Abstract. Oviposition habits of a univoltine mammalophilic blackfly, Prosimulium kiotoense Shiraki, were investigated at a stream in Kyushu Island, Japan. The flies oviposited on bryophyte mosses growing on river bank rock surfaces. The eggs were laid singly, but large irregular egg masses were often formed because many females oviposited within the same small areas. Wet sites with dense bryophyte cover at heights between 0 and 15 cm above water level were selected for oviposition. Oviposition activity was observed in the latter half of April. P. kiotoense females came to the site to lay eggs after 11.00 hours in the morning, when air temperature rose to about 15oC. Peak ovipositional activity occurred between 12.00 and 14.00 hours.