Transcriptional regulation of temperature stress response during development in the alfalfa leafcutting bee, Megachile rotundata

Insects can be significantly affected by temperature induced stress. While evidence of the physiological consequences of temperature stress is growing, very little is known about how insects respond at the genetic level to these stressors. The alfalfa leafcutting bee, Megachile rotundata, an emerging alternative pollinator, with its well-defined management protocols and molecular resources, presents a potent model for the study of temperature stress in insects. Standard rearing procedures involve M. rotunda being maintained at 6°C as prepupae and then brought up to 29°C for pupation and adult emergence. Because of M. rotudata’s role as a pollinator, those who manage them attempt to synchronize their emergence with flower bloom. If, because of unfavorable conditions, the peak flower bloom is delayed, the bees are placed into a low-temperature Static Temperature Regime (STR), known as interrupted development. This STR treatment results in increased mortality and flight defects in M. rotundata. However, when stored in a Fluctuating Temperature Regime (FTR), with daily pulses of 20°C, survival increases and developmental abnormalities are reduced.  In this experiment, the expression of candidate transcripts, identified in a previous RNA-seq experiment, were assessed throughout the duration of the seven-day treatment, and compared between STR and FTR treatments using qPCR. We hypothesize that periodic increase in temperature during FTR may act to promote proper neurological development in M. rotundata.