Investigating the unaccounted ones: insights on age-dependent reproductive loss in a viviparous fly

Most empirical and theoretical studies on reproductive senescence focus observable attributes of offspring produced, such as size or postnatal survival. While harder to study, an important outcome reproduction for a breeding individual is whether viable produced at all. prenatal mortality can sometimes be directly observed, this also indicated through increase in the interval between production. Both direct loss presumed losses have been found older females across several species. Here, we study (or “abortion”) tsetse, viviparous relatively long-lived fly with high maternal allocation. We consider how age-dependent patterns abortion depend developmental stage find that, per previous laboratory studies, higher rates late-larval stage, while egg-stage abortions are both very young females. track output little evidence that experiencing adaptive strategy improve future outcomes. After abortion, do not generally take less time produce their next offspring, these larger, there no sex bias towards females, fitness returns (being slightly larger longer-lived than males, insemination rates). Abortion stress, measured nutritional deprivation, which echoes work tsetse other species, i.e., humans baboons. discuss our results context taxa argue yet often overlooked trait vary age environmental stressors.