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Adaptive size modification by dominant female meerkats
Andrew F Russell1, Anne A Carlson, Grant M McIlrath
1Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom. a.f.russell@sheffield.ac.uk
Evolution; International Journal of Organic Evolution
|September 3, 2004
Summary
Female meerkats grow larger when they achieve dominant status, indicating adaptive morphological changes in cooperative vertebrates. This size increase enhances reproductive success and litter quality.
Area of Science:
- Behavioral Ecology
- Evolutionary Biology
- Animal Physiology
Background:
- Cooperative breeding in insects shows female reproductive size increases with group living.
- In vertebrates, morphological changes in breeding females are rare, noted only in naked mole rats (Heterocephalus glaber).
- The adaptive significance of morphological modification in breeding female vertebrates remains largely unexplored.
Purpose of the Study:
- To investigate morphological modifications in breeding female meerkats (Suricata suricatta), a cooperative carnivore.
- To determine if these morphological changes are adaptive and linked to reproductive success.
- To assess the prevalence of female morphological modification in cooperative vertebrates.
Main Methods:
- Comparative analysis of body size in female meerkats during dominant and subordinate phases.
- Statistical assessment to rule out age, foraging efficiency, and offspring care as causes for size differences.
- Hormonal analysis to explore potential mechanisms for bone growth.
Main Results:
- Female meerkats were significantly larger when dominant compared to when subordinate.
- Increased body size was not attributable to age, foraging, or caregiving.
- Larger dominant females produced larger litters with heavier offspring, correlating with breeding success.
Conclusions:
- Dominant female meerkats exhibit adaptive morphological changes, specifically increased body size.
- Hormonal influences may contribute to this size increase.
- Morphological modification in breeding female vertebrates may be more common than previously thought.