Takahashi Satoshi, Hori Michio
Department of Information and Computer Sciences, Nara Women's University, Kitauoyanishimachi, Nara 630-8506, Japan.
J Theor Biol. 2005 Aug 21;235(4):591-6. doi: 10.1016/j.jtbi.2005.02.014. Epub 2005 Mar 23.
Scale-eating cichlids in Lake Tanganyika exhibit genetically determined lateral asymmetry, especially in their mouth-opening. Frequencies of the morphs oscillate due to strong frequency-dependent selection caused by the switching of prey's attention, and its delayed effect by their growth period. Two scale-eaters coexist in similar densities at south shore of the lake, with their morph frequencies oscillating in phase. We investigated the effect of the oscillation in morph frequencies to the coexistence of competing species. If the difference of two species' growth period is large, the oscillation facilitates the coexistence of the two species, while small difference of growth periods hinders their coexistence. In the latter case, the species with shorter growth period drives the other species to the extinction.
坦噶尼喀湖中的食鳞丽鱼表现出由基因决定的侧向不对称性，尤其是在它们开口的方式上。由于猎物注意力的转移所导致的强烈频率依赖选择，以及其在生长周期中的延迟效应，这些形态的频率会发生波动。在湖的南岸，两种食鳞鱼以相似的密度共存，它们的形态频率同步波动。我们研究了形态频率的波动对竞争物种共存的影响。如果两个物种的生长周期差异很大，这种波动会促进这两个物种的共存，而生长周期差异较小时则会阻碍它们的共存。在后一种情况下，生长周期较短的物种会使另一个物种灭绝。
