In species of cooperative insects that live in large groups, selection for increased fecundity has led to the evolution of an increased body size among female reproductives, but whether this is also true of cooperative vertebrates is unknown. Among vertebrates, morphological modification of female breeders has only been documented in a single species; in naked mole rats (Heterocephalus glaber), acquisition of alpha status is associated with a significant increase in body size through an elongation of the lumbar vertebrae. Here we provide evidence of morphological modification among breeding females of a cooperative carnivore, the meerkat (Suricata suricatta), and demonstrate that this modification is likely to be adaptive. The same female meerkats were significantly larger when they were dominant than when they were subordinate. This increased body size was not explained by differences in age, foraging efficiency, or investment in offspring care, but may have arisen, in part, through increased levels of hormone that govern bone growth. Increases in body size are likely to result in fitness benefits, for large females delivered larger litters and had heavier offspring, both of which are known to correlate positively with measures of breeding success in meerkats. Our results suggest that the acquisition of alpha status in female meerkats is associated with an adaptive increase in body size and hence that morphological modification of female vertebrates may be more widespread than has been previously supposed.
How to translate text using browser tools
1 July 2004
ADAPTIVE SIZE MODIFICATION BY DOMINANT FEMALE MEERKATS
Andrew F. Russell,
Anne A. Carlson,
Grant M. McIlrath,
Neil R. Jordan,
Tim Clutton-Brock
ACCESS THE FULL ARTICLE
It is not available for individual sale.
This article is only available to subscribers.
It is not available for individual sale.
It is not available for individual sale.
Evolution
Vol. 58 • No. 7
July 2004
Vol. 58 • No. 7
July 2004
eusocial
fecundity
morphological modification
naked mole-rat
progesterone
vertebrate