Distribution England, Ireland, Scandinavia, through Central Europe to the southern Balkans.
Systematics Revision by Wagner (1985) placed Phymatopus hecta within monophyletic group also comprising Phymatopus species in Western North America.
Habitat Lowlands up to about 1500 m). Mainly in damp forest with understory plants (bracken, heather, bilberry), grassy or herbaceous forested areas. Prefers peat or clay silicate soils, rarely on calacareous soils, and avoids avoid dry calcareous biotypes (de Freina & Witt, 1990).
Biology Development usually two years, sometimes one year under favorable conditions. Males begin flying before sundown. Female flight is sluggish. Larvae feed on the roots of many plants including bracken (Pteridium aquilinum), cowslip (Primula), sorrel (Paeonia) (de Freina & Witt, 1990). In The Netherlands the most important host plant is the broad buckler fern Dryopteris dilatata (Post, F. 2006.) According to Stainton (1857, p. 110) feeding included the “roots” of moss, and leaves of dandelion. Wagner (1985) noted that the moss record needed confirmation and this was subsequently provided by Sterling & Heckford (2005) who discovered three final instar larvae under the moss Mnium hornum growing on the spreading roots of oak trees. The larvae were collected and reared on this moss. Stella Beavan and Bob Heckford (personal communication) also found a larva of P. hecta in open woodland where it had spun abundant silk over Mnium hornum on the ground. The larva occupied a tunnel in the soil but it was clear that it was feeding on the moss. The dandelion feeding noted byStainton (1857) represents a unique northern hemisphere record for foliage feeding in the Hepialidae.
References De Freina, J.J. & Witt, J.J.. 1990. Die Bombyces und Sphinges der Westpalaearktis. Verlag GmbH. München. Post, F. 2006.The heather rootborer Phymatopus hecta in acidified forests in southern Netherlands (Lepidoptera: Hepialidae). Nederlandse Faunistische Mededelingen 24, 13-20.
Phymatopus hectus male fanning metatibial scent scales. Image by Peter Meeuwenoord References continued Stainton, H.T. 1857.Manual of British Butterflies and Moths. John Van Voorst, London. (Link provided just for the Hepialidae). Sterling, P.H & Heckford, R.J. 2005. Moss as a pabulum for Hepialus hecta (Linnaeus, 1758) (Lep.: Hepialidae). The Entomologist's Journal and Record of Variation 117, 47. Turner, J.R.G. 2014. The dawn flight of the gold swift Hepialus hecta: predator avoidance and the integration of complex lek behavior (Lepidopera: Hepialidae). Biological Journal of the Linnean Society 110, 305-319.
Phymatopus hecta larva. Ashurst Wood, Hampshire, U.K. 4 April 2014. Image courtesy of Bob Heckford & Stella Beavan.