Experimental test of the influence of light availability on the evolution of eye size and behaviour in Daphnia
Experimental test of the influence of light availability on the evolution of eye size and behaviour in Daphnia
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DOI：
10.1111/jeb.14175
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发表时间：
2023-04
影响因子：
2.1
通讯作者：
Kaitlyn J Howell;Sarah Muh;B. Parajuli;M. Walsh
中科院分区：
文献类型：
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作者：
Kaitlyn J Howell;Sarah Muh;B. Parajuli;M. Walsh
眼睛的大小有很大的不同。许多工作已经提供了光可获得性与不同分类群之间眼睛大小差异之间的联系。光环境对眼睛大小进化的作用还缺乏实验测试。在这里，我们进行了一项选择实验，考察了光照对大型水蚤眼睛大小变化的影响，以及眼睛大小和趋光性(反捕食者)行为之间的关系。我们建立了水蚤的复制实验种群，在~50天的实验中反复评估眼睛大小的表型变化，并在实验结束时进行了一个普通的花园实验，以测试眼睛大小和行为的进化变化。我们的表型分析表明，眼睛大小在光处理之间迅速分化；相对眼睛大小在低光处理与强光处理中一致较大。对眼睛大小的选择也因密度的变化而改变，因为水蚤密度的增加有利于眼睛更大。然而，我们没有观察到在实验结束时经过两代普通花园饲养的光照处理之间的眼睛大小的差异。相反，我们观察到了反捕食者行为的强烈转变。弱光处理的水蚤对光的趋光反应减弱。我们的结果表明，光照减少会放松对捕食者行为的选择。这些趋势为眼睛大小和行为的选择提供了新的见解。
There exists extensive variation in eye size. Much work has provided a connection between light availability and differences in eye size across taxa. Experimental tests of the role of the light environment on the evolution of eye size are lacking. Here, we performed a selection experiment that examined the influence of light availability on shifts in eye size and the connection between eye size and phototactic (anti‐predator) behaviour in Daphnia. We set‐up replicate experimental populations of Daphnia, repeatedly evaluated phenotypic shifts in eye size during the ~50‐day experiment, and performed a common garden experiment at the end of the experiment to test for evolutionary shifts in eye size and behaviour. Our phenotypic analyses showed that eye size rapidly diverged between the light treatments; relative eye size was consistently larger in the low versus high light treatments. Selection on eye size was also modified by variation in density as increases in Daphnia density favoured a larger eye. However, we did not observe differences in eye size between the light treatments following two generations of common garden rearing at the end of the experiment. We instead observed strong shifts in anti‐predator behaviour. Daphnia from the low light treatment exhibited decreased phototactic responses to light. Our results show that decreased light relaxes selection on anti‐predator behaviour. Such trends provide new insights into selection on eye size and behaviour.