Gasteruption assectator

Taxonomy
Gasteruption assectator is a parasitic wasp species in the genus Gasteruption in the Gasteruptiidae family. 

Description
Gasteruption assectator are long and very slender with small specimens reaching around 13mm and larger specimens as big as 19mm. One of the unique characteristics of G. assectator is their long abdomen that is narrow at the base and widens to a broad end with a visible ovipositor. The abdomen is inserted high above the base of the hind legs. The end of the second and third segments of the gaster are reddish-brown, although the placement and number of markings can be somewhat variable. The front and middle legs are black at the base and lighten out to a brown or creamy color at the tips.

Nest Structure
Gasteruption assectator does not build its own nests, rather, it parasitizes the established nests of Hymenoptera species. Gasteruption assectator are considered to be generalists that parasitize a number of different species. In particular, G. assectator are known to parasitize the nests of Hylaeus bees. G. assectator lay their eggs next to Hylaeus eggs. The G. assectator eggs hatch first and the larvae consume the bee eggs they are laid next to. In MN Bee Atlas blocks, Gasteruption assectator parasitized Hylaeus verticalis nests.

Hole Sizes
In Bee Atlas blocks, Gasteruption assectator emerged from nests in upper column 3 tunnels (1/8 in), corresponding to the tunnel size used by their host, Hylaeus verticalis.

Voltinism
This species appears to be bivoltine in Minnesota but has been observed to be multivoltine in other locations.

Activity
Gasteruption assectator are active in Minnesota from mid-May through September.

References

Minnesota Seasons. Wild carrot wasp (Gasteruption assectator). [Online]. Available: http://www.minnesotaseasons.com/Insects/wild_carrot_wasp.html

Parslow, B. A., Schwarz, M. P., Stevens, M. I. 2020. Review of the biology and host associations of the wasp genus Gasteruption (Evanioidea: Gasteruptiidae). Zoological Journal of the Linnean Society 189(4): 1105-1122.