Evolutionary significance of ontogenetic color change in a hemipteran

Ontogenetic color changes are non-reversible color changes associated with normal progressive development of an individual of a species. A conceptual framework for understanding the ultimate reasons for ontogenetic color change is established using associated changes in sizes, reproductive status, and other characters.;Life history correlates of coloration in 54 species of Hemiptera were examined. Species with aposematically colored first instars laid more eggs per egg mass than species with cryptically colored first instars. Ontogenetic color changes were most common between first and second instars and between fifth instars and adults. The implications for predation avoidance strategies are discussed.;Largus californicus (Van Duzee) undergoes two dramatic ontogenetic color changes. First instar nymphs are red, second through fifth instar nymphs are black, and adults are black with orange edges on the pronotum and wings. The biology of L. californicus in coastal southern California is reported. Eggs are laid on the ground in clusters and nymphs are often found in clusters of ;Several aspects of aggregation in nymphal L. californicus were investigated experimentally. Both free ranging and caged bugs held outside underwent daily cycles of nighttime aggregation and daytime dispersal. By varying illumination, temperature, and humidity, it was determined that the bugs cluster most in response to dark, cold, had humid conditions. These results suggest a thermoregulatory function for clustering. Possible differences in thermoregulatory behavior between red first and black second instar nymphs are discussed.;Adult male mating behavior suggested that the change in color from black fifth instar nymphs to black and orange adults might enable males to discriminate between nymphs and adults. Female color patterns were altered and male's copulatory attempts were recorded to determine if color pattern was used by males in mating decisions. There were no significant differences in time to mount among the treatments or among control trials. Female color pattern did not affect male mating behavior under these conditions.