Thymelicus lineola (Ochsenheimer, 1808)

Host plants:
The larva feeds on grasses (Poaceae), especially Calamagrostis and Agropyron. The host plants of T. lineola and T. sylvestris overlap, but they have different focuses: sylvestris is more found on Holcus, Phleum and Phalaris.

Habitat:
Thymelicus lineola colonizes uncut or - in lower numbers - late cut grasslands of all kinds. The butterflies often occur together with Thymelicus sylvestris on fen meadows and clearcuts and along with this species and Thymelicus acteon in semi-arid grasslands. It also penetrates into arable areas and ruderal terrain. At Memmingen I observed Thymelicus lineola often on now mostly overbuilt ground excavatíon hills populated with camomiles and Agropyron repens.

Finally, there seems to be an slight peak in drier and warmer habitats, wheras Thymelicus sylvestris slightly prefers more humid habitats in Central Europe. But except for field edges there are hardly habitats in Central Europe where really only one of the two species occurs. However, a different frequency is often observed.

Life cycle:
I observed caterpillars often at Agropyron or Calamagrostis in late May and early June, usually a little later than those of Thymelicus sylvestris. The adults fly from late June through August. The oviposition occurs in small numbers (5-25) in leaf sheaths of grasses. The female lands on a blade and climbs backwards with searching abdomen tip downwards. If there is a suitable gap between the blade and a leaf sheath the eggs are deposited. The eggs are not visible from the outside. They are more elongate than the rounder eggs of T. sylvestris. If there is also the possibility of females dropping eggs into the vegetation, is still not clear. I observed such a behaviour many years ago, but that observation contrasts to many, many records of ovipositions into sheaths. Hibernation takes place as a larva within the egg shell. The young larva hatches in spring (March or April) and in the course of April the tubes of the young larvae are conspicuous for exercised eyes on young leaves of Calamagrostis. The mature larva may also live more freely on seat pads on grass leaves. Pupation also occurs in a leaf case.

Endangerment factors:
Thymelicus lineola is not endangered.

Remarks:
The distribution covers North Africa, Europe and large parts of temperate Asia. But it misses on many Mediterranean isles, so in the whole of the Aegean islands. In North America, Thymelicus lineola was introduced.