The effects of spatial habitat structure on the evolution of density-dependent growth and reproduction in freshwater snails
The effects of spatial habitat structure on the evolution of density-dependent growth and reproduction in freshwater snails
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DOI：
10.1007/s10750-004-2740-y
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发表时间：
2005-01-15
期刊：
影响因子：
2.6
通讯作者：
Ishibashi, Y
中科院分区：
文献类型：
--
作者：
Kawata, M;Sawada, H;Ishibashi, Y
我们研究了两种栖息地类型中淡水蜗牛（Physa acuta）的生长和繁殖率。在阿萨巴塔栖息地，蜗牛生活在孤立的水池中，这些水池偶尔会合并成一个大水池。在挂川栖息地，他们生活在缓慢流淌的水道中。使用三个微卫星位点的遗传结构评估支持了挂川栖息地有稳定的恐慌种群的观点。然而，微卫星数据显示，阿萨巴塔栖息地被另一种混合种群占据。当水位较低时，Asabata 种群可能会在孤立的水池内进行局部交配（如高 F-IS 和 F-IT 值所示），而当栖息地被洪水淹没时，会在 panmixia 内进行交配（如低 F-ST 值和 AMOVA 分析所示）。使用从两个栖息地收集的蜗牛进行的实验室实验表明，与挂川栖息地相比，浅羽栖息地的幼年蜗牛生长更快，产卵更多，并且产卵时间更早。在挂川栖息地，高密度下的生长率低于低密度下的生长率；在阿萨巴塔栖息地，情况正好相反。加贺川栖息地中个体蜗牛繁殖的密度依赖性响应高于浅田栖息地。结果支持这样的假设：空间结构影响密度依赖的增长率和繁殖时间的演变。
We examined the growth and reproductive rates of freshwater snails, Physa acuta, in two habitat types. In the Asabata habitat, snails lived in isolated water pools, which occasionally joined to form a single large pool; in the Kakegawa habitat, they lived in a slow-running water way. Genetic structure assessments using three microsatellite loci supports the idea that a stable panmictic population occupies the Kakegawa habitat. The Asabata habitat, however, is occupied with an alternate mixing population as revealed by microsatellite data. The Asabata population might alternate between localized mating within isolated pools (as revealed by high F-IS and F-IT values) when the water levels are low and panmixia (as revealed by the low F-ST values and AMOVA analysis) when the habitat is flooded. Laboratory experiments, using snails collected from the two habitats, showed that juvenile snails grew faster, laid more eggs, and laid them earlier in the Asabata habitat than in the Kakegawa habitat. Growth rates were lower at high density than at low density in the Kakegawa habitat; the inverse was true in the Asabata habitat. Density-dependent response of individual snail reproduction was higher in the Kakagawa habitat than in the Asabata habitats. The results support the hypothesis that spatial structure affects the evolution of density-dependent growth rates and of timing for reproduction.