Photoperiodic Control of Development in the Ant-Lion Hagenomyia micans (Neuroptera: Myrmeleontidae)
Furunishi, Sakuji; Masaki, Sinzo
The life cycle of the semivoltine species Hagenomyia micans Mc Lachlan 1875 was found to be mainly controlled by photoperiodic responses in the young and old larval stages. Larvae collected at various instars in IV-X matured within a narrow seasonal gate in the following summer under the naturally changing daylengths at 24°C. The L1 before hibernation moulted in a shorter time in long days than in short days at 21°C. A similar response occurred in timing the second ecdysis only when the food supply was poor. The L1 and L2 collected in spring and summer after hibernation, respectively, attained the L3 (last larval instar) without delay even in short days. However, the L3 permanently persisted as larvae in any stationary photoperiod. When they were exposed to longer photoperiods, only those which had experienced photoperiods shorter than 14 h pupated. It seems that the long-day type response is responsible for the first hibernation at the younger stage, and the short-day/long-day type response for the second hibernation at the last larval stage.