The shape of the trade-off function between egg production and life span in the parasitoid Asobara tabida

Despite a large number of studies on the cost of reproduction, the shape of the trade-off between reproduction and survival is still unresolved. In this paper, two prominent alternatives with respect to this problem are compared in the parasitoid Asobara tabida (Nees): a linear relationship between egg production and physiological life span, and a linear relationship between egg production and intrinsic mortality rate. This is the first study that directly assesses the shape of the trade-off function between reproduction and survival in an insect parasitoid. We manipulated egg production to be low, medium or high and measured the associated life span under laboratory conditions. The results showed a decrease in mean life span with increasing egg production. The data differed significantly from a trade-off function between egg production and mortality rate, while a linear trade-off function between egg production and physiological life span produced an accurate description of the data.