The ‘big spenders’ of the steppe: sex-specific maternal allocation and twinning in the saiga antelope
- 6 March 2007
- journal article
- Published by The Royal Society in Proceedings. Biological sciences
- Vol. 274 (1615), 1293-1299
- https://doi.org/10.1098/rspb.2007.0038
Abstract
In polygynous mammals, males generally benefit more from extra allocation of maternal resources than females. However, limitations to sex-specific allocation are usually ignored. We propose the 'allocation constraint' hypothesis, whereby maternal resource allocation is more likely to follow life-history predictions in single sex litters than in mixed sex litters, due to limitations in prenatal resource targeting. Consequently, for polygynous species, males in mixed litters are likely to receive suboptimal maternal investment, which may have a negative effect on lifetime reproductive success. We test this hypothesis for the saiga antelope (Saiga tatarica), a highly polygynous species with the highest level of maternal allocation reported among ungulates. At such high reproductive output levels, the limitations on additional investment in males are likely to be particularly acute. However, we demonstrate high levels of sexual dimorphism in both late-stage foetuses and newborn calves, including within the same litter. Male twins with a brother tended to be heavier than those with a sister. This may be due to allocation constraints or differences in maternal quality. We conclude that an explicit focus on potential constraints can enhance the progress in the field of sex-specific maternal allocation in polytocous species.This publication has 32 references indexed in Scilit:
- Sex allocation within broods: the intrabrood sharing-out hypothesisBehavioral Ecology, 2004
- The relative roles of density and climatic variation on population dynamics and fecundity rates in three contrasting ungulate speciesProceedings Of The Royal Society B-Biological Sciences, 2000
- The ecology and management of the Saiga antelope in KazakhstanMammal Review, 1998
- Adaptive variation in litter size and sex ratio at birth in a sexually dimorphic ungulateProceedings. Biological sciences, 1996
- Sexual Selection for Male Body Mass and the Evolution of Litter Size in MammalsThe American Naturalist, 1996
- Environmental effects on prenatal growth rate in pronghorn and bighorn: further evidence for energy constraint on sex-biased maternal expenditureBehavioral Ecology, 1995
- Sex-specific maternal investment in pronghorn, and the question of a limit on differential provisioning in ungulatesBehavioral Ecology and Sociobiology, 1990
- Fitness costs of gestation and lactation in wild mammalsNature, 1989
- The Theory of Sex Allocation. (MPB-18), Volume 18Published by Walter de Gruyter GmbH ,1983
- The Evolution of Social BehaviorAnnual Review of Ecology and Systematics, 1974