Are all eggs created equal? Food availability and the fitness trade-off between reproduction and immunity

摘要: Summary 1. Reproduction and immune function are critical processes, but organisms can rarely optimize both traits. Resultant reproduction–immunity trade-offs may be ‘facultative’, occurring only when resources scarce, or they ‘obligate’, regardless of resource availability. 2. Previous research has tested for the ‘facultative’ ‘obligate’ nature by measuring allocation (e.g. follicle size). However, alone insufficient gauging fitness consequences because number quality eggs offspring trade off with one another. 3. We used Texas field cricket (Gryllus texensis) to provide most direct test date whether a trade-off between these two traits is ‘obligate’. factorial design manipulate food availability status throughout adulthood. then estimated lifetime fecundity, hatching success their product (reproductive success), we also measured several aspects egg size protein content, hatchling energy stores). 4. A was in this species challenge reduced reproductive estimates Females unlimited were more fecund produced larger hatchlings, neither nor affected size, phenoloxidase activity, incubation duration, stores. observed – females favouring over fecundity fewer hatchlings higher (larger robust). 5. By demonstrating that not all created equal, key insight into role reproduction immunity.