Sex-specific catch-up growth in the Texas field cricket, Gryllus texensis

Abstract

Periods of poor nutrition during an organism's development can negatively impact its adult fitness. If conditions improve, an organism may increase its growth rate (compensatory growth) or delay maturity to increase body size (catch-up growth). Heightened resource allocation to growth, however, could impair resource availability for other fitness-related traits. Because each sex maximizes fitness differently, there might be sex-specific responses to improving conditions. In this study, we investigated compensatory/catch-up growth and its sex-specific costs in a field cricket. After a 4-week period of poor-quality food, treatment crickets were switched to a good-quality diet until maturity. We predicted that males and females would respond to this diet change differently, as the importance of large body size differs between sexes. Contrary to our prediction, we found that neither male nor female crickets increased their growth rates after realimentation compared with controls. Despite a lack of compensatory growth, both sexes attained the same average body size, mass, and condition at adulthood as control individuals. Females achieved the same size as controls by delaying their maturation age (i.e. via catchup growth) while males did not. Although the strategy used to catch-up differed between the sexes, its net effect on a suite of fitness-related traits was negligible in both sexes.