Paying the energetic costs of reproduction: reliance on postpartum foraging and stored reserves

Autor:in

Rödel, Heiko; Valencak, Teresa; Handrek, Alexandra; Monclús, Raquel

Abstrakt

Females have evolved different patterns of optimization of the allocation of energy to self-maintenance and to offspring production and care. In small mammals, females predominantly cover the energetic costs of reproduction by increasing their current energy income via increased foraging. Maternal endogenous reserves can also play a role in defining energetic allocation, reducing the concurrent feeding effort while reinforcing reproductive output. We studied reproductive allocation tactics in a small herbivore with high reproductive output, the European rabbit. In a field enclosure, we tested whether females' initial body mass and feeding effort around the time of parturition were associated with their reproductive effort by means of litter size and mass, and summed-up offspring growth as a proxy of mother's lactational performance. Reproductive effort by means of litter mass and offspring growth was higher in mothers with higher initial body mass. Females' feeding time budgets during lactation while carrying an additional pregnancy were increased by on average 24% compared with pregnant, nonlactating females and by 34% compared with nonpregnant females. On a gradual scale, females with higher reproductive output fed longer, apparently to meet the increased energy demands of reproduction. This was counterbalanced by the effects of mothers' initial body mass, as females with higher body mass spent less time feeding, most probably because they could rely on more endogenous reserves. Findings highlight that both stored capital and realized reproductive effort can interact in shaping patterns of postpartum feeding.

Dokumententyp

Originalarbeit

DOI

10.1093/beheco/arv217