ECOMORPHOLOGICAL CONVERGENCE OF CAVE COMMUNITIES
Article first published online: 6 AUG 2012
© 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.
Volume 66, Issue 12, pages 3852–3865, December 2012
How to Cite
Trontelj, P., Blejec, A. and Fišer, C. (2012), ECOMORPHOLOGICAL CONVERGENCE OF CAVE COMMUNITIES. Evolution, 66: 3852–3865. doi: 10.1111/j.1558-5646.2012.01734.x
- Issue published online: 3 DEC 2012
- Article first published online: 6 AUG 2012
- Accepted manuscript online: 16 JUL 2012 01:42PM EST
- Received April 15, 2012 Accepted July 4, 2012
- subterranean biology;
- troglomorphic adaptation
Extreme selective environments are commonly believed to funnel evolution toward a few predictable outcomes. Caves are well-known extreme environments with characteristically adapted faunas that are similar in appearance, physiology, and behavior all over the world, even if not closely related. Morphological diversity between closely related cave species has been explained by difference in time since colonization and different ecological influence from the surface. Here, we tested a more classical hypothesis: morphological diversity is niche-based, and different morphologies reflect properties of microhabitats within caves. We analyzed seven communities with altogether 30 species of the subterranean amphipod (crustacean) genus Niphargus using multivariate morphometrics, multinomial logit models cross-validation, and phylogenetic reconstruction. Species clustered into four distinct ecomorph classes—small pore, cave stream, cave lake, and lake giants—associated with specific cave microhabitats and of multiple independent phylogenetic origins. Traits commonly regarded as adaptations to caves, such as antenna length, were shown to be related to microhabitat parameters, such as flow velocity. These results demonstrate that under the selection pressure of extreme environment, the ecomorphological structure of communities can converge. Thus, morphological diversity does not result from adaptive response to temporal and ecological gradients, but from fine-level niche partitioning.