Behaviour 2019
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Gelada mothers spend less time feeding during pregnancy if birth is timed to peak
Sofia C. Carrera1, Amy Lu2, Jacinta C. Beehner1. 1University of Michigan, Ann Arbor, MI, United States; 2Stony Brook University, Stony Brook, NY, United States

Birth seasonality results when ecological factors limit a female’s ability to successfully reproduce. Even non-seasonal species often exhibit a birth peak that times a critical stage to an opportune time. The question is whether females that give birth outside this peak (“off-peak”) face energetic consequences. Here, we examine one possible cost, feeding time, in a non-seasonal primate, the gelada (Theropithecus gelada), which has a slight birth peak. We investigated the time females spent feeding based on whether they were “peak” or “off-peak” mothers. We analyzed female behavior during 37 pregnancies (from 2013-2017). Overall, compared to cycling, pregnant females increased feeding time in the second half of pregnancy by 20% (W=283, p=0.01). However, during early pregnancy, “off-peak” mothers spent 20-45% more time feeding compared to “peak” mothers (W=29, p< 0.01).  These results suggest that “off-peak” mothers might suffer higher metabolic costs than “peak” mothers. With increasing research into the effects of the early-life environment, this difference in birth timing could indicate an adverse environment for developing offspring.

Funding: NSF: DGE 1256260