Nysson interruptus (Fabricius,1798)

Synonyms

Ceropales spinosus Fabricius, 1804; Nysson panzeri Lepeletier, 1845; Nysson shukardi Wesmael, 1852

Description and notes

The rarest of our four Nysson species, with British populations seemingly using a different host to those in Fennoscandia. It is similarly threatened in Germany.

Distribution

Confined to southern England (Cornwall, Devon, North Somerset, Dorset, Hampshire, Isle of Wight, Sussex, Surrey, Essex, Middlesex, Berkshire and Oxfordshire) and the Channel Islands. Abroad, recorded from most European countries and Asia Minor (Lomholdt, 1975-76).

Status (in Britain only)

Listed as Vulnerable (RDB2) by Falk (1991) and Rare (RDB3) in Shirt (1987); the former status reflecting the obvious decline with few modern records. Post-1970 information is restricted to sites in Sussex, the Isle of Wight and the Channel Islands (Guernsey and Sark). A reappraisal of its status may be necessary.

Habitat

Presumed to resemble that of its host, with soft rock cliffs, coastal landslips and heaths featuring strongly in British data. The host is particularly reliant on vertical earth banks or sparsely vegetated slopes for nesting. On the Isle of Wight, G R Else (pers. comm.) found the adults mainly flying around bramble bushes (but not visiting the flowers).

Flight period

Late May to early August.

Flowers visited

Various umbellifers and bramble (Rubus); also scabious (Knautia and Succisa) in Fennoscandia, and yarrow (Achillea millefolium) and stonecrop (Sedum sp.) in France (Bitsch et al, 1997).

Parasites

No information available.

Parasitic biology

Nysson interruptus is clearly the special cleptoparasite of Argogorytes fargei, with much data to support this including an observation of the Nysson entering an A. fargei nest in Devon (Perkins, 1923). In Fennoscandia, Lomholdt cites Gorytes quadrifasciatus and the non-British G. quinquecinctus as hosts with no mention of A. fargei.

Author of profile

S J Falk.

Year profile last updated

Proofed: March 2012