Direct male-male competition can facilitate invasion of new colour types in Lake Victoria cichlids

Dijkstra, Peter D.; Seehausen, Ole; Groothuis, Ton G. G. (2005). Direct male-male competition can facilitate invasion of new colour types in Lake Victoria cichlids. Behavioral ecology and sociobiology, 58(2), pp. 136-143. Springer 10.1007/s00265-005-0919-5

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The possibility that disruptive sexual selection alone can cause sympatric speciation is currently a subject of much debate. The initial difficulty for new and rare ornament phenotypes to invade a population, and the stabilisation of the resulting polymorphism in trait and preference make this hypothesis problematic. Recent theoretical work indicates that the invasion is facilitated if males with the new phenotype have an initial advantage in male-male competition. We studied a pair of sympatric incipient species of cichlids from Lake Victoria, in which the red (Pundamilia nyererei) and blue males (P. pundamilia) vigorously defend territories. Other studies suggested that red phenotypes may have repeatedly invaded blue populations in independent episodes of speciation. We hypothesised that red coloration confers an advantage in male-male competition, assisting red phenotypes to invade. To test this hypothesis, we staged contests between red and blue males from a population where the phenotypes are interbreeding morphs or incipient species. We staged contests under both white and green light condition. Green light effectively masks the difference between red and blue coloration. Red males dominated blue males under white light, but their competitive advantage was significantly diminished under green light. Contests were shorter when colour differences were visible. Experience of blue males with red males did not affect the outcome of a contest. The advantage of red over blue in combats may assist the red phenotype to invade blue populations. The apparently stable co-existence of red and blue incipient species in many populations of Lake Victoria cichlids is discussed.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE) > Aquatic Ecology

UniBE Contributor:

Seehausen, Ole

Subjects:

500 Science > 570 Life sciences; biology

ISSN:

0340-5443

Publisher:

Springer

Language:

English

Submitter:

Marcel Häsler

Date Deposited:

05 Sep 2014 12:09

Last Modified:

05 Dec 2014 05:52

Publisher DOI:

10.1007/s00265-005-0919-5

Uncontrolled Keywords:

Cichlids, Lake Victoria, Sexual selection, Speciation, Male-male competition

BORIS DOI:

10.7892/boris.49522

URI:

https://boris.unibe.ch/id/eprint/49522

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