Garden swift moth

The moths have a wingspan of 25-40 mm, with yellowish brown forewings that are variously marked with white, especially in the males. The hindwings are yellowish grey. The eggs are 0.5 mm in diameter, almost spherical and whitish when laid but turning black soon thereafter. The larvae are up to 35 mm long, whitish, shiny and partly translucent. The dark gut is clearly visible. The head and the prothoracic plate are light brown. The pupa is approximately 20 mm long and brown with ventral projection on the abdominal segments.

Adult garden swift moths fly at dusk in May or June and occasionally also in August and September, often over grassland in large numbers. The females broadcast up to 300 eggs at random whilst in flight. The larvae feed in the soil on roots of many plants. They make narrow feeding burrows in the soil where they retreat if disturbed. The larvae are often unearthed during soil cultivation.

The caterpillars feed throughout the winter and usually pupate around April; sometimes the development takes another year. Pupation takes place in a loosely woven silken tunnel between the roots. After about six weeks the pupae wriggle to the soil surface where they remain protruding after the adults have emerged. Flushes of newly emerged moths often appear after rainfall.