Rahman Md Moshiur, Turchini Giovanni M, Gasparini Clelia, Norambuena Fernando, Evans Jonathan P
Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley, Western Australia, Australia.
School of Life and Environmental Sciences, Faculty of Science, Engineering and Built Environment, Deakin University, Warrnambool Campus, Warrnambool, Victoria, Australia.
PLoS One. 2014 Aug 29;9(8):e105856. doi: 10.1371/journal.pone.0105856. eCollection 2014.
Environmental and ecological conditions can shape the evolution of life history traits in many animals. Among such factors, food or nutrition availability can play an important evolutionary role in moderating an animal's life history traits, particularly sexually selected traits. Here, we test whether diet quantity and/or composition in the form of omega-3 long chain polyunsaturated fatty acids (here termed 'n3LC') influence the expression of pre- and postcopulatory traits in the guppy (Poecilia reticulata), a livebearing poeciliid fish. We assigned males haphazardly to one of two experimental diets supplemented with n3LC, and each of these diet treatments was further divided into two diet 'quantity' treatments. Our experimental design therefore explored the main and interacting effects of two factors (n3LC content and diet quantity) on the expression of precopulatory (sexual behaviour and sexual ornamentation, including the size, number and spectral properties of colour spots) and postcopulatory (the velocity, viability, number and length of sperm) sexually selected traits. Our study revealed that diet quantity had significant effects on most of the pre- and postcopulatory traits, while n3LC manipulation had a significant effect on sperm traits and in particular on sperm viability. Our analyses also revealed interacting effects of diet quantity and n3LC levels on courtship displays, and the area of orange and iridescent colour spots in the males' colour patterns. We also confirmed that our dietary manipulations of n3LC resulted in the differential uptake of n3LC in body and testes tissues in the different n3LC groups. This study reveals the effects of diet quantity and n3LC on behavioural, ornamental and ejaculate traits in P. reticulata and underscores the likely role that diet plays in maintaining the high variability in these condition-dependent sexual traits.
环境和生态条件能够塑造许多动物生活史特征的进化。在这些因素中，食物或营养的可获得性在调节动物的生活史特征，尤其是性选择特征方面，能够发挥重要的进化作用。在此，我们测试了以ω-3长链多不饱和脂肪酸（以下称为“n3LC”）形式存在的饮食数量和/或组成，是否会影响孔雀鱼（Poecilia reticulata）（一种卵胎生硬骨鱼）交配前和交配后特征的表达。我们将雄性孔雀鱼随机分配到两种添加n3LC的实验饮食之一，并且每种饮食处理进一步分为两种饮食“数量”处理。因此，我们的实验设计探究了两个因素（n3LC含量和饮食数量）对交配前（性行为和性装饰，包括色斑的大小、数量和光谱特性）和交配后（精子的速度、活力、数量和长度）性选择特征表达的主要影响和交互作用。我们的研究表明，饮食数量对大多数交配前和交配后特征有显著影响，而n3LC的调控对精子特征，特别是精子活力有显著影响。我们的分析还揭示了饮食数量和n3LC水平对求偶展示以及雄性体色模式中橙色和虹彩色斑面积的交互作用。我们还证实，我们对n3LC的饮食调控导致不同n3LC组的身体和睾丸组织对n3LC的摄取存在差异。这项研究揭示了饮食数量和n3LC对孔雀鱼行为、装饰和射精特征的影响，并强调了饮食在维持这些依赖条件的性特征的高变异性方面可能发挥的作用。
