Data from: Sympatry predicts spot pigmentation patterns and female association behavior in the livebearing fish Poeciliopsis baenschi

In this study, we explored the possibility that differences in pigmentation patterns among populations of the fish Poeciliopsis baenschi were associated with the presence or absence of the closely related species P. turneri. If reproductive character displacement is responsible, spotting patterns in these two species should diverge in sympatry, but not allopatry. We predicted that female P. baenschi from sympatric sites should show a preference for associating with conspecifics vs. heterospecific males, but females from allopatric sites should show no such preferences. To evaluate these predictions, we compared spotting patterns and female association behaviors in populations of P. baenschi from Central Mexico. We found that both of our predictions were supported. Poeciliopsis baenschi that co-occured with P. turneri had spotting patterns significantly different than their counterparts from allopatric sites. Using a simultaneous choice test of video presentations of males, we also found that female P. baenschi from populations that co-occured with P. turneri spent significantly more time with males of their own species than with P. turneri males. In contrast, females from allopatric populations of P. baenschi showed no differences in the amount of time they spent with either conspecific or heterospecific males. Together, our results are consistent with the hypothesis that reproductive character displacement may be responsible for behavioral and spotting pattern differences in these populations of P. baenschi.本研究旨在探究巴氏花鳉（Poeciliopsis baenschi）不同种群间的体色斑纹差异，是否与近缘物种特纳花鳉（Poeciliopsis turneri，简称P. turneri）的存在与否存在关联。若生殖特征置换（reproductive character displacement）为该差异的成因，则两个物种的斑纹模式应在同域分布（sympatry）区域产生分化，而异域分布（allopatry）区域则无此分化。我们提出如下预测：来自同域分布区域的巴氏花鳉雌性个体，会更倾向于与同种雄性结伴，而异域分布区域的雌性个体则无此类偏好。为验证上述预测，我们对墨西哥中部地区巴氏花鳉种群的斑纹模式以及雌性结伴行为进行了比较分析。研究结果证实了两项预测均成立：与特纳花鳉同域共存的巴氏花鳉种群，其斑纹模式与异域分布的种群个体存在显著差异。通过雄性视频同步选择实验，我们进一步发现，与特纳花鳉同域共存的巴氏花鳉雌性个体，在同种雄性与特纳花鳉雄性的视频展示中，会花费显著更长的时间与同种雄性相关联；与之相反，来自异域种群的巴氏花鳉雌性个体，在与同种或异种雄性相关联的时间占比上无显著差异。综合来看，本研究结果支持“生殖特征置换是导致巴氏花鳉不同种群间行为模式与斑纹模式差异的成因”这一假说。