Hoopoe males experience intra-seasonal while females experience inter-seasonal reproductive costs.

Abstract

Reproductive and survival costs due to reproductive investment are a central element for the evolution of life histories. Both intra- (reduction of reproductive performance of second brood due to investment in first brood) and inter-seasonal costs (reduction of reproductive performance or annual survival due to reproductive investment in preceding year) may appear in multiple breeding species. Knowledge about how trade-offs within and between seasons shape individual trajectories and influence fitness are crucial in life-history evolution, yet intra- and inter-seasonal reproductive costs are rarely analysed simultaneously. We investigated sex-specific differences in intra- and inter-seasonal reproductive and survival costs in response to previous reproductive effort in a monogamous, double-brooding bird, the hoopoe (Upupa epops), accounting for heterogeneity in individual and annual quality. Intra-seasonal reproductive costs were detected in males and inter-seasonal reproductive and survival costs were detected in females. In males, the probability of being a successful double breeder was negatively correlated with the number of hatchlings produced in the first brood. In females, the number of fledglings raised in the first brood was negatively correlated with the reproductive effort in the preceding season. Female annual survival was also negatively influenced by the number of broods produced in the previous reproductive season. Most of these reproductive costs were detected only in years with low productivity, suggesting that costs become evident when environmental conditions are harsh. Our results illustrate how different investment in current vs. future reproduction and survival shape different life-history strategies in males and females of a monogamous bird species.