De heidewortelboorder Phymatopus hecta in verzuurde bossen in Zuid-Nederland (Lepidoptera: Hepialidae).

The gold swift Phymatopus hecta in acidified forests in the southern part of the Netherlands (Lepidoptera: Hepialidae) The gold swift Phymatopus hecta (Linnaeus, 1758) is a small moth which occurs in woods on peaty and sandy soils. The moth belongs to the family of the Hepialidae of which the young caterpillars feed on the roots of herbaceous plants. It was assumed that the species is declining in the Netherlands. During a research undertaken in 2004 and 2005 the species appears to be common in woods in a large area in the south of the Netherlands. Based on observations from other researchers the species seems to be fairly common on the sandy and peaty soils in the middle, east en north of the Netherlands. The most important host plant is the broad buckler fern Dryopteris dilatata. This plant has expanded in old pine woods and profits from the acidification of the soils caused by emissions from transport, industry and agriculture. The top of the flight period lies at the beginning of June, which is about one to two weeks earlier than mentioned in the literature. The presence of the gold swift can be determined by visiting rich populations of ferns at dusk. The fact that this method is not much used any more is the cause for the presumed decline and has in fact covered up an expansion.