Clonal Niche Structure in the Parthenogenetic Earthworm Octolasion tyrtaeum
Jaenike J, Parker ED, Selander RK. 1980. Clonal Niche Structure in the Parthenogenetic Earthworm Octolasion tyrtaeum. The American Naturalist. 116(2):196-205
Clones of parthenogenetic species provide an opportunity to study the niches of individual genotypes. Octolasion tyrtaeum, a parthenogenetic earthworm, was collected in Tennessee, North Carolina, and New York in a variety of habitat types differing in soil pH, soil texture, and vegetation, which are important niche dimensions for earthworms. Eight genetically distinct clones were identified by starch-gel electrophoresis at 10 structural gene loci. Six of these clones were present in only a few collections, and therefore information on their potential niches is limited. The other two clones, which were widespread and abundant, are broad niched and apparently very similar ecologically. In fluctuating environments, selection favors "general purpose" genotypes, which are relatively insensitive to environmental changes, and which therefore are probably ecologically similar. Because soil and vegetation types form a mosaic pattern, only broad-niched clones can be widespread if dispersal occurs actively through the habitat. If the two dominant clones of O. tyrtaeum are nearly identical ecologically, as they appear to be, one might expect competitive exclusion or clonal "drift" where they occur together, whereas stable coexistence could result if they differ in their niches.
- Type
- Journal Article
- Authors
- Jaenike, John; Parker, E; Selander, Robert
- Units
- GRSM
- Keywords
- Animal Studies, earthworms (Oligochaeta), Great Smoky Mountains National Park, GRSM-01093, Habitats, NC, TN