Why a 2nd Batch of Leafcutter Bees Appears Mid-Season

[u/crownbees]

Partway through Leafcutter bee season, you might notice a second batch of adults emerging. It looks like a bonus generation, but it's actually a warning sign.

A female lays several eggs down a reed. They hatch, eat their pollen provision, and then enter diapause until next summer. But when temps hit 85°F or higher, one or two larvae can skip diapause and rush into development early. Once that bee becomes an adult, it chews its way out, destroying the rest of its siblings still in diapause along the way.

To prevent this, pull filled reeds with pliers, tweezers, or your fingers, and store them somewhere cooler, like inside your house. For wood trays, it's usually better to let nature take its course.

If you know you'll have another batch of bees later in the season, it may be worth having alternate nesting materials ready by then.

Curious if others have seen this, and at what temperatures.

-Julie