Oscillation Maintains Polymorphisms — a Model of Lateral Asymmetry in Two Competing Scale-eating Cichlids
✍ Scribed by Satoshi Takahashi; Michio Hori
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 284 KB
- Volume
- 195
- Category
- Article
- ISSN
- 0022-5193
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✦ Synopsis
Scale-eating cichlids in Lake Tanganyika exhibit lateral asymmetry polymorphism in their mouth-opening. Frequency of left-and right-handed phenotypes oscillates around unity. In the southern shore of the lake, two scale-eaters coexist in similar densities, where their oscillations synchronize. This phenomena is analysed by a time-delay differential equation model, and a new mechanism which maintains polymorphism is discovered. In a wide range of parameters, the oscillation keeps the frequencies of the same phenotype in the two species at a similar level, and prevents the fixation of one phenotype in either species.