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 tradeoff between reproduction and survival is still unresolved. In thi s paper, two prominent alternatives with respect to this problem are compar ed in the parasitoid Asobara tabida (Nees): a linear relationship between e gg production and physiological life span, and a linear relationship betwee n 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 as sociated life span under laboratory conditions. The results showed a decrea se in mean life span with increasing egg production. The data differed sign ificantly a trade-off function between egg production and mortality rate, w hile a linear trade-off function between egg production and physiological l ife span produced an accurate description of the data.