Offspring sex varies with maternal investment ability: empirical demonstration based on cross-fostering

Robert, Kylie A., Schwanz, Lisa E., and Mills, Harriet R. (2010) Offspring sex varies with maternal investment ability: empirical demonstration based on cross-fostering. Biology Letters, 6 (2). pp. 242-245.

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Despite decades of interest, adaptive explanations for biased offspring sex ratios in mammals remain contentious, largely because direct tests of the underlying fitness assumptions of adaptive hypotheses are rarely conducted. These tests are complicated by the difficulty of manipulating offspring sex prior to significant maternal investment owing to the biological constraints of viviparity. We test the adaptive advantage of sex allocation through cross-fostering offspring by sex in tammar wallabies. We examine whether offspring sex is correlated with maternal investment ability (i.e. Trivers–Willard hypothesis, TWH). In addition, we test the assumption that maternal investment has a greater influence on the fitness of sons than of daughters. We failed to find statistical support for maternal investment ability influencing a son's weaning success or body size more than a daughter's, although this result was probably owing to small sample sizes. In support of the TWH, females that gave birth to a son had higher investment ability (likelihood of weaning an offspring) regardless of the sex of offspring fostered.

Item ID: 17002
Item Type: Article (Research - C1)
ISSN: 1744-957X
Keywords: sex allocation; sex ratio; marsupial; maternal condition; Trivers–Willard hypothesis; cross-fostering
Date Deposited: 12 May 2011 05:57
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060201 Behavioural Ecology @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 100%
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