Ecology of Migrating Colorado Potato Beetles (Coleoptera: Chrysomelidae) in Western Massachusetts

The age structure, reproductive status, and sex ratio of migrating and dispersing adults of Lepiinotarsa decemlineata (Say) in a potato field in western Massachusetts was determined. Movement by flight (local and migratory) occurred predominantly in adults 7–13 d old. Although significantly more males engaged in local flight activity, possibly in search of mates, males and females were equally likely to migrate by flight. The majority of postdiapause females (73.3%)subsampled from windowpane trap collections reproduced. Only 38.9%(1985) and 44.4%(1986) of first-generation females oviposited, and 89.5%(1985) and 67.7% (1986) of the females that did not oviposit were collected after the first part of August; this was explained by induction of diapause. The applicability of current migration theory to the Colorado potato beetle and the role of migration in the life history strategy of this insect are discussed.