THE OVIPOSITION PROCESS IN 2 DIRECT BREEDING GENERATIONS IN A WATER STRIDER, AQUARIUS-PALUDUM (FABRICUS)

In the first generation (nymphal stage, about 20-degrees-C on average in Kochi) of a water strider, Aquarius paludum (Fabricius), the preoviposition period was longer than in the second generation (> 27-degrees-C) in both macropterous and brachypterous forms under natural conditions. The adults of both wing-forms showed lower fecundity in the early reproductive period than in the late one in the first generation. The oviposition process in the second generation, however, was the opposite of the first generation. Half of the females in the second generation entered diapause after the reproductive period. A high temperature of 28 +/- 2-degrees-C in the nymphal stage induced a shorter preoviposition period and higher fecundity than a low temperature of 20 +/- 2-degrees-C in both wing-forms. A stepwise reduction in photophase (14.5-12-10 h) in the early adult stage caused lower fecundity than a reduction of 14.5-10 h.