Scathophaga Stercoraria - Life Cycle

Life Cycle

The eggs that the female lays on the dung pat will hatch into larvae after 1–2 days, depending on temperature. The larvae quickly burrow into the dung for protection and feed on it. At 20°C, larvae undergo three molts over five days, during which they grow exponentially. After growth, larvae spend another five days emptying their stomachs before pupation, where no additional body mass is gained. After 10–20 days the larvae burrow into the soil around and beneath the dung and pupate. The time needed for the juvenile flies to emerge can vary from 10 days at 25°C to 80 days at 10°C or less. The smaller females typically emerge a few days before the males. The fitness of the resulting juveniles is greatly dependent on the quality of the dung in which they were placed. Factors affecting dung quality include water content, nutritional quality, parasites, and drugs or other chemicals given to the animal.

Yellow dung flies are anautogenous. In order to become sexually mature and produce viable eggs or sperm they must feed on prey to acquire sufficient proteins and lipids. Females under nutritional stress will have higher rates of egg mortality and less survival of offspring to adult emergence. Scathophaga stercoraria can then produce anywhere from 4 to 10 clutches per lifetime. The adults are active throughout much of the year in most moderate climates.