Abstract
Five life tables for eggs to adults of the bean miner, Ophiomyia phaseoli, were constructed based on an examination of young kidney bean seedlings sampled from the field at 2-4 day intervals during July-August in 1979 and '81, December-March in 1979-'80 and 1980-'81, and April-May in 1980. About 500 kidney bean seedlings were planted in the field at the beginning of each survey season and the plant growth was checked at 2 developing leaf stages by hand-picking the ensuing leaves so as to reduce variation in the amount and period of eggs deposited among the plants. At each sampling, 20 seedlings were taken at random from the seedlings showing signs of egg deposition or larval inhabitation. The differences in the initial number (1x) of eggs were not great among four of the five life tables, e.g. 265-432 eggs per 20 plants, except the one experiment where only 91 eggs were laid per 20 plants. However, the total survival rate from eggs to adults was apparently seasonally dependent since it was much higher in summer (14-20 %) than in winter (3-6 %) or in spring (8 %). The causes of such seasonal dependence in the total survival rate seems related to the pupation site probably located at the lower part of the plant stem or beneath the soil in summer in contrast to the pupation site frequently seen at the upper part of plant stem in winter. Such a seasonal change in pupation site would affect the action of pupal parasites (Pteromalids) and cause more or less the escape of the fly population in summer.
