RESPONSES TO SELECTION AMONG LIFE-HISTORY TRAITS IN A NONMIGRATORY POPULATION OF MILKWEED BUGS (ONCOPELTUS FASCIATUS).

Genetic parameters were assessed in the nonmigratory Puerto Rico population of the milkweed bug, Oncopeltus fasciatus, and compared with parameters estimated in a migratory population from Iowa (Palmer and Dingle, 1986). Offspring-parent regression analysis provided initial estimates of heritabilities and phenotypic and genetic correlations among wing length, head-capsule width, female age at first reproduction, fecundity for the first and second five days of reproduction by females, and clutch size for the first and second five days of reproduction by females. Replicated bidirectional selection for wing length was then imposed, with a direct response to selection revealing substantial additive genetic variance for this trait, as was also the case with the Iowa population.

DIRECT AND CORRELATED RESPONSES TO SELECTION AMONG LIFE-HISTORY TRAITS IN MILKWEED BUGS (ONCOPELTUS FASCIATUS).

Offspring-parent regressions provided initial estimates of heritabilities and genetic correlations among wing length, body length, pronotum width, head-capsule width, development time, age at first reproduction, and fecundity in an Iowa population of the large milkweed bug, Oncopeltus fasciatus. Replicated, bidirectional selection for wing length was imposed for nine generations. The direct response to selection revealed the existence of substantial additive genetic variance for wing length in this population.