D3408: Not a degree day model: predicting how incubation temperature changes affect alfalfa leafcutting bee emergence

The alfalfa leafcutting bee, Megachile rotundata, is a solitary bee that is intensely managed for pollination services. One consistent problem that managers must deal with is synchronizing bee emergence with crop bloom, which is exacerbated by the fact that a one month incubation is required before emergence begins. Although cold storage can be employed to delay emergence, this has been shown to increase mortality and give rise to sublethal effects that diminish pollination efficiency. Here we propose a simple model that managers can use to determine emergence time at temperatures above this insect’s developmental threshold. This would allow for the use of these less injurious temperatures while still being confident in predicting dates of emergence.