Davey, P., 2009: A rare species in Britain confined to the Breck district and along the Thames estuary, the larva feeding on the seeds of charlock (Sinapis arvensis) and white mustard (Sinapis alba) in the Breck, and the seeds of perennial wall-rocket (Diplotaxis tenuifolia), along the Thames estuary. In Dorset, the moth has been recorded in all but one of the past seventeen years, but there are no records prior to 1987. With the exception of singletons from Puddletown and Gaunts Common, all examples have been from the coastal fringe, and most have coincided with immigration events. The status of the moth is therefore a regular but infrequent immigrant.
The national norm is a single-brood in June and July, but the Dorset records suggest two broods, the first in June, and a much larger second brood between early-August and mid-September. This bivoltine pattern is more a reflection of the cycle abroad rather than that experienced in the UK. Both charlock and white mustard ‘arable weeds’, have declined considerably in response to the widespread use of herbicides, and consequently there appears to be little scope for this species to gain a permanent foothold in the county. |