ABSTRACT

Iris lutescensis a common species occurring mainly in dry limestone habitats in Western Italy, Southern France, and Spain. The species shows a remarkable polymorphism for flower colour, and yellow and purple flowers can be found in the same population. As the species is a deceptive one, the previous studies on the maintenance of such a polymorphism were linked to its pollination ecology. Here, I reported on the spatial distribution of the polymorphism and showed that Spanish populations are mostly purple monomorphic. In contrast, populations in the South of France and Italy show the complete range, from 0 to 1, for the frequency of yellow morph, and the spatial autocorrelation for morph frequencies is very low. To go further, correlations between morph frequencies and abiotic factors, such as bioclimatic variables, UV irradiance, and aridity, were studied. On the whole, the spatial distribution of the frequency of yellow morph can be hardly explained by the contributions of these abiotic variables, and historical contingencies, including the phylogeography of the species have to be invoked, in particular, to explain the absence of polymorphic populations in Spain.

摘要

Iris lutescensis 一种常见的物种，主要出现在意大利西部、法国南部和西班牙的干燥石灰岩栖息地。该物种在花色方面表现出显着的多态性，在同一种群中可以发现黄色和紫色的花朵。由于该物种是一种具有欺骗性的物种，之前关于维持这种多态性的研究与其授粉生态学有关。在这里，我报告了多态性的空间分布，并表明西班牙种群大多是紫色单态性。相比之下，法国南部和意大利的人口显示黄色变体频率的完整范围，从 0 到 1，变体频率的空间自相关非常低。更进一步，变形频率与非生物因素之间的相关性，例如生物气候变量、紫外线辐照度和干旱，被研究。总的来说，这些非生物变量的贡献很难解释黄色变种频率的空间分布，必须援引历史偶然性，包括物种的系统地理学，特别是解释多态性种群的缺失在西班牙。