Abstract
Females of Microctonus vittatae Muesebeck reared at 20°C were darker in colour than females reared at 25°C but were lighter than those reared at 15°C. Temperature during the parasite’s larval or pupal development in the cocoon, or both, was apparently responsible for the colour differences. The observed effect of temperature is probably also associated with colour variability among adults of M. vittatae field-collected throughout the season.