Phymatopus

The gold swift (Phymatopus hectus), originally belonging to the genus Hepialus, is widely distributed across Europe (central and northern) and the Ural Mountains, follows the distribution of its food plant - bracken and roots of Erica, Primula, Rumex, Calluna. The male forewings bear two silvery white stripes consisting of individual spots separated by dark veins, which are fringed with thin black lines. The dorsal process of valvella (part of male genitalia) is almost straight, and the mesosome tip is rounded.[2]

Phymatopus hecta japonicus is found located in the Russian Far East: Sakhalin island and southern Kurils; south of the Daisetsu mountains, Hokkaido, Japan. Its appearance is similar to P. hectus but differs in that the outer strip is usually uninterrupted. It consists of four or five silvery spots at the apex (anterior corner), two or three small spots moving slightly more inward and the largest one at the inner margin. The morphology of the male genitalia is also different from that of P. hectus, the ventral process of valvella is belt like, which tapers to a point as it reaches the distal quarter, the dorsal margin of valva is convex. P. japonicus from Sakhalin has a maximum male wingspan of 25–26 mm and shows pale or greyish brown colouring on the forewings, whereas the male specimens from Kurilan tend to have a larger wingspan of 30–31 mm, bright, reddish brown. The male genitalia also differs between specimens of Kurilian population and from Sakhalin, with Kurilian males having shorter mesosomes and a rounded tip of valva distal projection, as opposed to a tapering tip in Sakhalin males.[2]

Phymatopus hecticus is found in eastern Russia. The forewing stripes are usually composed of golden-yellow or whitish coloured confluent spots without metallic lustre. In male genitalia, the dorsal process of valvella is strongly curved in the distal part, giving it a hook-like appearance; there is also a clear cavity at the tip of the mesosome.[2]

Phymatopus hecticus albomaculatus is found in eastern Russia, north of Primorskii krai. Both forewing stripes have a silvery-white appearance, with a metallic tinge, similar to Phymatopus hectus and Phymatopus haponicus, also consisting of separated spots. However, they have differences in male genitalia; the shape of the eighth abdominal sternum and tip of mesosome. The length of forewing is about 14 mm in males, with a curved inner strip. The outer strip consists of three separated spots at the apex and two smaller spots moving inwards.[2]

Phymatopus are root and stem borers.[4] It is not uncommon for the larvae to tunnel through the stems, as is the case of the western North American Phymatopus. Tunnels can be found travelling through the base of the stems and also the adjacent stems in contact with leaf litter and soil. Sometimes dead stems can also serve to provide tunnels which are active. As well as tunnelling through stems, some larvae (e.g. P. hectoides) tunnel through the soil and feed on root tissues.[5]

In the pupae, one or two fixed basal abdominal segments. On the abdominal segments, there are dorsal spines aligned in rows, similar to some lower members of the Heteroneura.[3]