Department of Integrative Biology, University of Texas Austin, Austin, TX, USA.
Genes Brain Behav. 2014 Apr;13(4):365-75. doi: 10.1111/gbb.12124. Epub 2014 Mar 19.
Female mate choice is fundamental to sexual selection, and determining molecular underpinnings of female preference variation is important for understanding mating character evolution. Previously it was shown that whole-brain expression of a synaptic plasticity marker, neuroserpin, positively correlates with mating bias in the female choice poeciliid, Xiphophorus nigrensis, when exposed to conspecific courting males, whereas this relationship is reversed in Gambusia affinis, a mate coercive poeciliid with no courting males. Here we explore whether species-level differences in female behavioral and brain molecular responses represent 'canalized' or 'plastic' traits. We expose female G. affinis to conspecific males and females, as well as coercive and courting male Poecilia latipinna, for preference assays followed by whole-brain gene expression analyses of neuroserpin, egr-1 and early B. We find positive correlations between gene expression and female preference strength during exposure to courting heterospecific males, but a reversed pattern following exposure to coercive heterospecific males. This suggests that the neuromolecular processes associated with female preference behavior are plastic and responsive to different male phenotypes (courting or coercive) rather than a canalized response linked to mating system. Further, we propose that female behavioral plasticity may involve learning because female association patterns shifted with experience. Compared to younger females, we found larger, more experienced females spend less time near coercive males but associate more with males in the presence of courters. We thus suggest a conserved learning-based neuromolecular process underlying the diversity of female mate preference across the mate choice and coercion-driven mating systems.
雌性的配偶选择对性选择至关重要，而确定雌性偏好变化的分子基础对于理解交配特征的进化很重要。此前的研究表明，在暴露于同种求偶雄性时，突触可塑性标志物神经丝氨酸蛋白酶的全脑表达与雌性选择的孔雀鱼 Xiphophorus nigrensis 的交配偏好呈正相关，而在没有求偶雄性的配偶强制孔雀鱼 Gambusia affinis 中，这种关系则相反。在这里，我们探讨了雌性行为和大脑分子反应的种间差异是否代表“定型”或“可塑性”特征。我们将雌性 Gambusia affinis 暴露于同种雄性和雌性以及强制和求偶的雄性波西米亚鱼 Poecilia latipinna 中，进行偏好测试，然后对神经丝氨酸蛋白酶、egr-1 和早期 B 的全脑基因表达进行分析。我们发现，在暴露于求偶异性雄性时，基因表达与雌性偏好强度之间呈正相关，但在暴露于强制异性雄性时则呈相反模式。这表明与雌性偏好行为相关的神经分子过程是可塑的，并对不同的雄性表型（求偶或强制）有反应，而不是与交配系统相关的定型反应。此外，我们提出，雌性行为的可塑性可能涉及学习，因为雌性的关联模式随着经验而变化。与年轻的雌性相比，我们发现更大、更有经验的雌性在强制雄性附近花费的时间更少，但在有求偶者的情况下与雄性的关联更多。因此，我们建议存在一个保守的基于学习的神经分子过程，它是跨选择交配和强制交配系统的雌性配偶偏好多样性的基础。
