Sociality level correlates with dispersal ability in spiders
Article first published online: 18 MAY 2012
© 2012 The Authors. Functional Ecology © 2012 British Ecological Society
Volume 26, Issue 4, pages 794–803, August 2012
How to Cite
Corcobado, G., Rodríguez-Gironés, M. A., Moya-Laraño, J. and Avilés, L. (2012), Sociality level correlates with dispersal ability in spiders. Functional Ecology, 26: 794–803. doi: 10.1111/j.1365-2435.2012.01996.x
- Issue published online: 16 JUL 2012
- Article first published online: 18 MAY 2012
- Received 1 September 2011; accepted 21 March 2012 Handling Editor: Charles Fox
- evolution of sociality;
- feedback mechanisms;
- social spiders;
- subsocial spiders
1. The evolution of sociality alters the genetic structure of populations, often leading to an increase in the level of inbreeding and a concomitant decrease in the ratio between the benefits and costs of dispersal.
2. The association between an absence of dispersal and sociality in spiders has so far been established indirectly from the age distribution of colonies, their genetic structure and their sex ratio. Using a functional and mechanistic approach, we investigated the dispersal tendencies and abilities of individuals of both sexes in species of spiders with different degrees of sociality. We predicted that dispersal tendencies and abilities would decrease when sociality increased.
3. In seven species of Anelosimus (Theridiidae), we tested whether there is a sharp transition between dispersing subsocial species and non-dispersing social ones, or whether dispersal ability decreases more gradually as level of sociality increases and whether both sexes are equally affected. Our assays measured the propensity and ability to bridge, a common aerial locomotion mode in spiders that is especially relevant during pre-mating dispersal.
4. We found that the tendency to disperse by bridging and, at least in males, the ability to disperse, significantly decrease as the level of sociality increases, and that this occurs without a pronounced threshold between subsocial and social species. Additionally, we detected a reduction of leg length relative to body size with increasing sociality and decreasing dispersal abilities in males, which may be mechanistically related to their reduced ability to bridge.
5. We propose that the loss of dispersal ability associated with the evolution of sociality in spiders, especially in males, could contribute to the maintenance of their inbred social systems by substantially increasing dispersal costs.