Species Account for Nysson dimidiatus

Essex Red Data List comment
cleptoparasite on Gorytes tumidus

Species text
Nysson dimidiatus has records from scattered localities throughout England and Wales as far north as Northumberland but it is a very local species with about 25 known post-1970 sites. Both N. dimidiatus and its host are likely to have declined during this century, in response to the loss and deterioration of sandy habitats such as heathland, and from coastal development. This species and its main host favour warm sunny areas, especially south-facing slopes in sheltered spots, where the host excavates its nests in bare and sparsely vegetated ground. It is a cleptoparasite of the local sphecid wasp Harpactus (Gorytes) tumidus, with which it is usually taken and closely resembles. Scrub invasion and the loss of bare sand has resulted from changes in land use and the decline in rabbit populations following the introduction of myxomatosis. At some sites, horse riding and motorcycle activity could jeopardise the future of the species, though at others some disturbance will probably be beneficial in promoting the presence of bare and sparsely vegetated ground. References

Habitats

Recorded management for locations with Nysson dimidiatus

Recorded substrate and hydrology for locations with Nysson dimidiatus

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