Coleophoridae

37.102 Yarrow Case-bearer Coleophora argentula (Stephens, 1834)

Common

Similar species:

Forewing: 4.5 to 6mm

Habitats: Verges, embankments, downland and wasteland.

Habits: The moth flies at sunrise, in the evening and at night.

Foodplant: The larvae initially feed internally on the seeds within the withering flowers and seed-capsules of Yarrow, Sneezewort and occasionally Ribwort Plantain. The gregarious larvae move from seed-capsule to seed-capsule, spinning them together and forming silk galleries. The early case is at first almost white, but the fully formed case is brown, cylindrical and spattered with plant debris giving it a rough surface. It is trivalved and 5 to 6mm long, m.o. at a 0° to 10° angle. The cases are often abundant on the seed-heads in October. At this time they become full-fed and leave to overwinter, although some stay in the seed-heads. The larvae pupate in early June, usually near the ground.