Megachile rotundata is an agriculturally important pollinator of alfalfa and is not doing well in the U.S due to a 50% return rate (Pitts-Singer and Bosch, 2011). Nesting boxes can reach temperatures between 35˚C-48˚C (see Chapter 2). These temperatures can cause damage to multiple stages of development, including death (Barthel et al. 2002, Rossie et al. 2010). To date, it is unclear how cavity temperature varies across the box. Traditionally, nesting cavity temperatures have been monitored using 1-3 temperature probes to measure thousands of cavities (CaraDonna et al. 2018). These methods do not account for the accuracy of the temperature probe to depict temperatures several cm away from the probe. To asses this variation I have designed a 3D printed nesting box that holds one temperature probe for every four cavities. I found that cavity temperature impacts nesting preference, and survival, of the alfalfa leafcutting bee.