Molecular studies on Drosophila melanogaster do not provide consistent results with regard to the hormonal regulation of a trade-off between life-span and fecundity. To unravel the physiological basis of the cost of reproduction without affecting animal's genotype, a new insect model, Pyrrhocoris apterus, was employed. Reproduction was manipulated by surgical ablations of tissues implicated in reproductive endocrinology, namely the pars intercerebralis (PI) of the brain, the corpus allatum (CA) and the ovary, and the response of life-span to these interventions under diapause-promoting short days and reproduction-promoting long days was measured. Life-span of long-day females increased in the following order: control (high fecundity)=ovary-ablation (no egg production)