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Extension > Yard and Garden News > Ignore Andrenid Bees

Wednesday, April 29, 2015

Ignore Andrenid Bees


Jeffrey Hahn, Extension Entomologist

Andrenid bees are a type of native ground-nesting bee that is first seen during early spring. Residents are discovering them now in their gardens and lawns.  Some people have been concerned that these insects may be ground dwelling yellowjackets (wasps) but the overwintering queens are only just starting to build new nests and people would not be seeing any activity from their nests this early.

Andrenid bees like to nest in sunny, dry areas of gardens
and yards. Photo: Jeff Hahn, UMExtension
Unlike honey bees and bumble bees which are social insects, andrenid bees are solitary so there is only one bee in a nest. But they are gregarious which means that there are many nests in a small area. They prefer to construct their nests in loose soils, like sandy or sandy loam soils. It is common to find andrenid bee nests on dry sunny slopes or small hills. The nests are somewhat mounded up and can resemble ant nests.

Andrenid bees are important pollinators. Tolerate them
whenever possible. Photo: Jeff Hahn, UMExtension
An andrenid bee is about ½ inch long with a black abdomen (sometime it has bands of hair giving it a striped appearance) and has whitish or yellowish hairs on its thorax (the segment behind the head). They are very gentle, docile insects and are extremely unlikely to sting even when there is activity around their nests. Since they are the only bee in their nest, they do not defend it like social bees and wasps would; they need to avoid being injured or killed so they can maintain their nests and care for their young.

These native bees are very important pollinators and should be tolerated. They are active for several weeks, and then complete their life cycle. They are gone on their own by May so they are only present during spring.

1 comment:

  1. We have a huge population of andrenid's by our front door. We plan to do construction in this area soon. Do their nests need to be relocated or will they move on their own after the life cycle? How do we prevent their return?

    ReplyDelete

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