The Induction of Emergence in the Leaf-Cutter Bee Megachile rotundata, an Important Pollinator of Alfalfa1

Abstract

Laboratory tests on the time-temperature relationships for the development of diapausing prepupae of the leafcutter bee Megachile rotundata (F.), showed the favorable range to extend from 19° to approximately 38°C. Below 19° development does not occur and above 38° mortality is complete. Peak temperature for development was 32°. Development is temperature-dependent and the position of the cell in the series has no effect on the maturation rate. Alternating temperatures caused a consistent delay in the onset of emergence, as well as in the time of peak emergence, even though the lower of the temperatures was within the favorable range. Recommendations are made for commercial management of overwintering prepupae.