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Species guide - species detail

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Melittobia sp. (Tiny parasitic wasps)



Melittobia wasps are small parasitic wasps in the family Eulophidae. Melittobia are the most common parasites in Bee Atlas blocks. We did not identify Melittobia to species.


To the naked eye, Melittobia appear to be small dark specks, approximately 1.0-1.5 mm long. Females are fully winged, but males have reduced wings and eyes, and cannot fly. Unlike other nest parasites that lay their eggs in the host nest while it is built, Melittobia can chew through cell walls and lay eggs on the host prepupae any time after the nest has been constructed. They are not host-specific and parasitize many different bee and wasp species.

Nest Structure

In Bee Atlas blocks, Melittobia parasitized a wide range of bees and wasps, including Osmia and Megachile species, eumenid wasp species, and sphecid wasp species. However, most nests that were parasitized by Melittobia did not produce any host offspring. When parasitized Megachile nests were opened at the end of the rearing season, we often found perfect-looking nests with bee cocoons filled with frass and no recognizable bee parts. Closer inspection found tiny holes in the leaf lining where the Melittobia had chewed through the nest walls.

Hole Sizes

Melittobia emerged from many hole sizes due to the variety of their host species. Each Melittobia "specimen" includes many individuals that emerged as a group from a nest (see pictures).


No information at this time.

Activity Period

No information at this time.


Matthews, Robert W., González, Jorge M., Matthews, Janice R., & Deyrup, Leif D. (2009). Biology of the Parasitoid Melittobia (Hymenoptera: Eulophidae) *. Annual Review of Entomology, 54(1), 251-266. Thank you to John Luhmen for help identifying parasitic wasps

Minnesota Record Map

These data are from the Minnesota Bee Atlas project.

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