Reducing losses to offspring mortality by redistributing resources

1. It is shown that reallocation of resources from dying offspring to their surviving siblings leads to significant reductions of fitness losses due t o early developmental errors. 2. The reason resource reallocation can improve offspring fitness is becaus e mothers do not provide offspring with the optimal amount of resources fro m the offspring's point of view. Rather, mothers trade their investment per offspring off against the number of offspring. Hence, surviving offspring can use reallocated resources fruitfully. 3. Animals suffering high offspring mortality can reduce this cost by produ cing large packages of resources shared by offspring. This allows for bette r reallocation of resources. Furthermore, by overstocking their resource pa ckages with eggs they can anticipate embryo mortality and obtain offspring that will on average be more optimal in size. 4. In accordance with our prediction, parthenogenetic flatworms studied her e produce larger cocoons than sexuals and they overstock smaller cocoons wi th eggs. However, higher embryo survival in large cocoons may also explain both these phenomena.