Davey, P., 2009: One of the most abundant moth species in Britain (the adult female is capable of producing up to two thousand eggs), the larva feeding nocturnally on various herbaceous plants and grasses. In Dorset, the moth is ubiquitous and common to abundant, especially in open areas. Occasionally huge aggregations of the moth occur, and light traps at such times become inundated often at the expense of the more interesting species. The following light trap records are of single night catches in excess of eight hundred moths. All are on or very close to the coast and most coincided with notable immigrations from abroad, where it is a known migrant: West Bexington, 1000 on 16 July 1996, 870 on 27 July 2001 (R Eden), St Albans Head, 1500 on 7 August 1992 (P Davey), Arne Wood, 1150 on 14 July 1978 (B Pickess), Durlston, 2000 on 29 July 1992, 1000 on 2 September 1998 (P Davey), 5000 on 26 June 2003 (P Davey, S Nash), 1240 on 7 August 2003 (J McGill), Highcliffe, 3000 on 13 July 1982 (E Wild).

Although the adult is stated to fly between late June and early September, the flight period stretches from late-May to mid-November in Dorset, a period of nearly six months. Male adults are said to live for up to three months, whereas females live up to four months. It is likely that the moth aestivates during the summer as it does abroad, and this behaviour may explain the dip in numbers between late July and the early September, see phenology chart. The following individuals were recorded at light traps on very early dates and with airflows from southern Europe on each occasion, these are likely to have been primary immigrants: West Bexington, on 25 April 1996, 30 March 2003 (R Eden), Motcombe, 3 May 2006 (P Butter), Wool, on 2 May 2003 (D Cooper), Gaunts Common, two on 29 April 1994 (P Davey), Durlston, 1 May 2005 (P Davey, G Hopkins), Poole, 1 May 2007 (V Giavarini), St Ives, on 4 May 1989 (Dr J Clarke), Hengistbury Head, on 4 May 2003 (M Jeffes).

There is much variation in the coloration of the forewings of both sexes, and this is clearly evident when the moth is at rest. However, variation in the colour of the hindwings is rarely noted, as the hindwings remain tucked away out of sight until the moth becomes airborne. The only variety noted in the county is ab. postnigra trapped at Durlston on 26 June 2003 (P Davey), where the usual orange-yellow was suffused with black, making the hindwings appear caramel-coloured.