Life history response of a predatory ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), to food stress

Abstract

The ladybird beetle, Harmonia axyridis (Pallas), was studied under laboratory condition to reveal the effect of food stress on phenotypic changes in life history traits that reflect larval and adult performance. Two food environments (abundant and limited food availability) were used as experimental treatments. When the food was limited, larvae grew slowly. Surviving adults were smaller, and their pre-reproductive period was considerably prolonged, reproductive life span and fecundity were reduced, and longevity was increased. On limited food supply, adults had reduced efficiency of converting food into eggs in comparison to adults provided abundant food supply. The relationships between lifetime fecundity and female longevity suggested that for both food levels, there were two groups of individuals with one group showing a positive correlation and the other group a negative correlation between reproduction and longevity. Life history responses to food stress, and the trade-off between fecundity and female longevity, are discussed.