Department of Psychology, Neuroscience Program, Smith College, Northampton, MA, USA.
Physiol Behav. 2012 Oct 10;107(3):271-6. doi: 10.1016/j.physbeh.2012.09.001. Epub 2012 Sep 13.
Mammalian offspring sex ratios can be biased via prenatal and postnatal mechanisms, including sperm selection, sex-specific embryo loss, and differential postnatal investment in males and females. Syrian hamsters routinely cannibalize some of their pups in the first days after birth. We present evidence that short day lengths, typically predictive of poor autumn and winter field conditions, are associated with male-biased sex ratios, achieved in part through selective perinatal maternal infanticide of female offspring. Higher peak litter sizes were associated with increased cannibalism rates, decreased final litter counts, and increased body mass of pups surviving to weaning. To our knowledge this is the first report of sex ratio adjustment by offspring cannibalism.
哺乳动物后代的性别比例可以通过产前和产后的机制产生偏差，包括精子选择、性别特异性胚胎丢失，以及雄性和雌性后代的不同产后投资。叙利亚仓鼠通常会在出生后的头几天内吃掉部分幼崽。我们提供的证据表明，短日照时间通常预示着秋季和冬季野外条件不佳，与雄性偏多的性别比例有关，这部分是通过选择性围产期母体杀死雌性后代来实现的。更高的高峰期窝仔数与更高的同类相食率、较低的最终窝仔数和存活到断奶的幼仔体重增加有关。据我们所知，这是首次通过后代同类相食来调节性别比例的报告。
