Sexual dimorphism and the differential mortality model: is behaviour related to survival?
Article first published online: 7 JAN 2003
Biological Journal of the Linnean Society
Volume 78, Issue 1, pages 97–103, January 2003
How to Cite
WALKER, S. E. and RYPSTRA, A. L. (2003), Sexual dimorphism and the differential mortality model: is behaviour related to survival?. Biological Journal of the Linnean Society, 78: 97–103. doi: 10.1046/j.1095-8312.2003.00134.x
- Issue published online: 7 JAN 2003
- Article first published online: 7 JAN 2003
- Received 28 February 2002; accepted for publication 29 August 2002
- sexual size dimorphism;
- differential mortality
There are numerous hypotheses to explain the evolution of sexual dimorphism in spiders. One of the most controversial is the differential mortality model (DMM) which proposes that differing rates of (adult) male and female mortality can result in a skewed operational sex ratio and lead to the evolution of small males. This hypothesis has been examined using a comparative approach which assumes that the behaviour of males and females could be used as a surrogate measure of mortality. We tested this assumption using two model species, Hogna helluo and Pardosa milvina (Araneae: Lycosidae) that differ in the degree of sexual dimorphism both in terms of body size and level of activity. Our data demonstrate that differences in male and female behaviour are not predictive of differences in mortality. Rather, as in other organisms, mortality is a complex phenomenon dependent on activity as well as size. These data call into question the methods previously used to test the DMM and suggest that understanding sexual size dimorphism (SSD) in spiders will require evaluation of historical constraints as well as how size currently influences fitness in each sex. © 2003 The Linnean Society of London. Biological Journal of the Linnean Society , 2003, 78, 97−103.