抄録
Larvae of the onion fly, Hylemya antiqua were reated under several combination of temperatures (10-22°C) and photoperiods (16L-8D and 12L-12D) to determine the effect of these factors on the larval development and diapause induction. Photoperiod little affected the developmental zero temperature for larva development (4.3°C under 16L-8D, and 4.6°C under 12L-12D), whereas the total effective temperature necessary for such development was a little greater in the short day (257 day-degrees under 16L-8D, and 278 day-degrees under 12L-12D). When pupae obtained from different conditions were kept at 25°C, 16L-8D, most flies emerged 9-18 days after pupation, but some were observed to emerge 40-60 days after pupation. This latter was particularly common in cultures at the lower temperatures and short photoperiod. We regarded the individuals emerging within 20 days after pupation as "non-diapausing" and the rest as "diapausing". The temperature inducing diapause in 50% of individuals was found to be significantly affected by photoperiod : 14.0°C under 16L-8D, and 18.5°C under 12L-12D.
