Data from: Global biogeography of mating system variation in seed plants

Latitudinal gradients in biotic interactions have been suggested as causes of global patterns of biodiversity and phenotypic variation. Plant biologists have long speculated that outcrossing mating systems are more common at low than high latitudes owing to a greater predictability of plant–pollinator interactions in the tropics; however, these ideas have not previously been tested. Here, we present the first global biogeographic analysis of plant mating systems based on 624 published studies from 492 taxa. We found a weak decline in outcrossing rate towards higher latitudes and among some biomes, but no biogeographic patterns in the frequency of self-incompatibility. Incorporating life history and growth form into biogeographic analyses reduced or eliminated the importance of latitude and biome in predicting outcrossing or self-incompatibility. Our results suggest that biogeographic patterns in mating system are more likely a reflection of the frequency of life forms across latitudes rather than the strength of plant–pollinator interactions.

生物交互作用的纬度梯度格局，此前被提出为全球生物多样性与表型变异分布格局的潜在成因。植物生物学家长期以来推测，受热带地区植物-传粉者交互作用（plant–pollinator interactions）可预测性更强的影响，异交交配系统（outcrossing mating system）在低纬度地区的发生频率高于高纬度地区；然而，这一假说此前尚未得到实证检验。本研究依托涵盖492个分类群（taxa）的624项已发表研究，开展了全球首个植物交配系统的生物地理学分析。研究结果显示，随着纬度升高以及部分生物群区（biome）的变化，异交率呈现微弱下降趋势，但自交不亲和性（self-incompatibility）的发生频率并未表现出显著的生物地理格局。将生活史（life history）与生长型（growth form）纳入生物地理分析框架后，纬度与生物群区对异交率或自交不亲和性的预测效力被大幅削弱，甚至完全消除。本研究表明，植物交配系统的生物地理格局，更可能是不同纬度区间内生活型分布频率的反映，而非植物-传粉者交互作用强度的体现。