Convergence and Parallelism in Cave Entomobryinae

Author

Kenneth Christiansen

Files

Publication Date

9-1-1961

Publication Title

Evolution

Volume Number

15

Issue Number

3

Abstract

The evolution of the holarctic cave Collembola of the subfamily Entomobryinae is analyzed. A number of evolutionary lines are shown, involving the two polyphyletic genera Pseudosinella and Sinella in Japan, North America, and Europe. Characteristics of these animals are of two types: cave dependent (responding rapidly to the cave environment) and cave independent (showing no effect of the cave environment). The evolution of the cave organisms is divided into three stages. The first stage represents the level of adaptation normally found in troglophile organisms, although some troglobites are found in the stage. All such forms are very limited in their cave distribution, and occupy a few caves around the periphery of major cave habitats. The second stage of evolution shows more cave adaptation, but the evolutionary pathways are varied, with convergence, parallelism, and divergence common. Most forms within this stage are troglobites, but there are a few troglophiles, and many of the organs characteristic of the stage occur as preadaptations in some putative ancestral forms. The members of this stage are abundant and relatively widespread. Within the third evolutionary stage convergence is universal, and the organs characteristic of these forms are limited to cave members of the family. Forms falling within this stage are relatively abundant but extremely limited in distribution. The probable adaptive significance of several organ modifications characteristic of troglobite forms is discussed, and these structures are interpreted as positive adaptations to the new requirements of cave life which have the final result of closely limiting the animals to the cave environment.

Document Type

Article

Digital Object Identifier (DOI)

https://doi.org/10.2307/2406229

Language

English

Recommended Citation

Christiansen, Kenneth, "Convergence and Parallelism in Cave Entomobryinae" (1961). KIP Articles. 10742.
https://digitalcommons.usf.edu/kip_articles/10742