Biology

Hepialus humuli adults:

  • Have non-functional mouthparts and do not feed.
  • Fly at dusk and early at night in June and July.

Reproduction

The male ghost moths attract females by emitting scent pheromones from large hair tufts on their hind legs during a slow, hovering and pendulating flight. 

This flight usually takes place either:

  • low over the vegetation
  • up and down in front of a tree trunk

The males generally perform the flight in groups of a few dozen to a few hundred individuals, but swarms of several thousands have been observed.

Life cycle

1. Eggs are laid

Eggs are oval and shining white. They are laid by being dropped to the ground by the female while in flight. This haphazard egg-laying behaviour, combined with an extraordinarily large number of eggs, is quite common in the entire family.

Hepialus humuli larva

The shiny, whitish, brown-headed Hepialus humuli larva. © Chris Harlow

2. Larvae hatch

The shiny, whitish, brown-headed larvae live in tunnels in the soil where they feed on the roots of various herbs and grasses. Despite the species epithet, humuli, meaning 'off the hop', Hepialus humuli does not have a special preference for hop (Humulus). 

Larval development lasts from July to April.

3. Larvae pupate

Pupation takes place in the tunnel. The pupa is considerable more mobile than most moth pupae, and moves itself to the surface when the adult is ready to emerge.

4. Adults emerge and try to breed

Adults can be found throughout much of June and July.