A new solitary grass carrying wasp to look out for in your nest boxes?

Isodontia mexicana, is a species of grass-carrying wasps, found in the United States. Notton states that c. 1940 it was accidentally imported into Hawaii, then c. 1960 southern France and now has spread into the Netherlands, Belgium and N. France. They use pre existing holes as nests sites, similar to many solitary wasps and bees here in the UK. They make their nests using fresh cut grass blades, which shortly dry out and turn brown. The grass is used to partition the individual brood cells, then provision them with prey items for their larvae.

Grass carrying wasp, Isodontia mexicana, now in the UK

They use grasshopper or bush cricket nymphs as prey items for their larvae. They will paralyse the nymphs and then their larvae eat them alive!

Grass carrying wasps hunt grasshopper and bush cricket nymphs for their young to feed upon

Isodontia mexicana according to BWARS was first discovered in SE London in 2016 and in 2017, David Notton, Natural History Museum produced a paper about it.

With thanks to Diego Garcia for film materials in Switzerland using a Nurturing Nature Observation Nest Box

Thanks to Simon Sexton for suggesting it was likely this wasp.

It would make a nice addition for me to film myself if it ever spreads north!

NB. These prey items are bush cricket nymphs, not grasshopper nymphs. Thanks to D Notton for correction.

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