Overwintered Colorado potato beetles,Leptinotarsa decemlineata(Say), collected from the soil at South Deerfield, Mass., in the spring of 1989 were brought to the laboratory and individually fed potato foliage or left unfed. Beetles were tethered to a flight mill for 1h daily to measure the number of flights, their distances, and time per flight when on the mill. Unfed beetles flew more often, for longer periods, and for greater distances (on average, a total of 4,879 m for unfed females compared with 1,346 m for fed females). Many (17 of 27) fed beetles flew for short distances (>5 m) before initiating oviposition; a smaller number (6 of 22) flew>200 m during any flight bout before laying their first eggs. Unfed female beetles laid virtually no eggs, whereas fed females laid an average of 22 eggs/d. Overwintered females that were unmated in the spring did not differ in egg production from spring-mated females, but egg viability was significantly higher. Results show that a single overwintered female constitutes a mobile and fecund founder of populations. The complex life history of the Colorado potato beetle uses migration and diapause to distribute offspring over space and time, thus minimizing reproductive risk.