Boneset Clearwing Borer
Head: Brown-black. Nose cone (palpi) orangish-yellow, tip black. Orange-yellow stripe across back of head.
Antenna: Long, reaching to mid-wing. Black, thickening toward tips on male. Tips curved and pointed on both male and female.
Thorax: Brown-black with 2 yellow longitudinal lines, one at each side.
Wings: Forewing brown-black entirely on female. Male may have a thin yellow streak before mid-wing and some yellow streaks near wing tip. Hindwing transparent with wide black border and fringe.
Legs: Dark with various amounts of yellowish to whitish scaling. Male has hind shin (tibiae) yellow. Feet pale.
Abdomen: Abdomen brown-black. Fourth segment has a wide, bright yellow band. Male also has a narrow band on last segment. Female tip entirely black, brush-like with a square tip. Male tip pointed, sometimes with yellow fringe at each side.
Size: 5 to 11 mm long. Wingspan 12 to 23 mm. Females large, males small.
Habitat: Moist to wet areas, stream and river banks, ditches. Also along railway lines or gravelly areas.
Food: Adults feed on flower nectar. Larvae feed in lower stems and roots of Common Boneset Eupatorium perfoliatum growing in damp places, and Tall Throughwort Eupatorium altissimum which is native only to Pelee Island and inventive, usually along railway lines and gravelly soil in the rest of Ontario. Tall Throughwort is listed as S1 (endangered) in Ontario. Larvae do not feed on Joe-Pye Weeds Eutrochium purpureum and E. maculatum, previously named Eupatorium.
Flight Time: August to mid-September.
Life Cycle: Females deposit light yellow, oblong eggs on the underside of Boneset leaves usually near the base of the plant. Larvae drill into the leaf stem, then into the main plant stem, forming tunnels down to the root crown. Over-winters as a half-grown larvae in the tunnels. Mature larvae are 14 mm long, dirty white, head light brown, bi-lobed, slightly hairy. Shield and legs brown. The next spring, they move up the tunnels and create an exit hole, then pupate in the tunnel (20 days). They emerge as adults in early morning and mate within an hour. One generation per year.
Comments: Rare. Listed for Ontario, but only 2 other individuals found: BugGuide from Hastings, near Peterborough and Karwatha Lakes by Lake Simcoe. Essex County – Wheatley in 2014 only.
DNA problems. BOLD had 2 samples ‘suppressed’ by GenBank although Carmenta pyralidiformis is unique – the only Clearwing Borer with one wide yellow band on abdomen.
For information on synonyms, references and type specimens see next page