Data from: Sex at the margins: parthenogenesis vs. facultative and obligate sex in a Neotropical ant

Geographic parthenogenesis is a distribution pattern, in which parthenogenetic populations tend to live in marginal habitats, at higher latitudes and altitudes and island-like habitats compared with the sexual forms. The facultatively parthenogenetic ant Platythyrea punctata is thought to exhibit this general pattern throughout its wide range in Central America and the Caribbean Islands. Workers of P. punctata from the Caribbean produce diploid female offspring from unfertilized eggs by thelytokous parthenogenesis, and mated females and males are rare. In contrast, workers in one colony from Costa Rica were incapable of thelytoky; instead mated workers produced all female offspring. Because sample sizes were very low in former studies, we here use microsatellite markers and explicit tests of thelytoky to examine the population genetic structure of ancestral and derived populations of P. punctata throughout the Caribbean and Central America. Populations from the Caribbean islands were fully capable of parthenogenesis and population genetic signatures indicate that this is the predominant mode of reproduction, although males are occasionally produced. In contrast, the northernmost population on the mainland (Texas) showed signatures of sexual reproduction and individuals were incapable of reproduction by thelytoky. Contrary to expectations from a geographic parthenogenesis distribution pattern, most parts of the mainland populations were found to be facultatively thelytokous, with population genetic signatures of both sexual and parthenogenetic reproduction.地理孤雌生殖（Geographic parthenogenesis）是一种分布格局：相较于有性生殖种群，孤雌生殖种群更倾向于栖息于边缘生境、高纬度与高海拔区域以及类岛屿生境。兼性孤雌生殖的扁头猛蚁（Platythyrea punctata）被认为在其分布于中美洲与加勒比群岛的广阔范围内呈现这一通用分布格局。来自加勒比地区的P. punctata工蚁可通过产雌孤雌生殖（thelytokous parthenogenesis）由未受精卵子产生二倍体雌性后代，且交配雌性与雄性个体较为罕见。与之相反，哥斯达黎加的一个蚁群中的工蚁无法进行产雌孤雌生殖；取而代之的是，交配工蚁可产生全部雌性后代。由于既往研究的样本量极低，本研究借助微卫星标记（microsatellite markers）与产雌孤雌生殖的严格检验方法，对分布于加勒比地区与中美洲的P. punctata祖先种群及衍生种群的种群遗传结构展开探究。加勒比群岛的种群完全具备孤雌生殖能力，种群遗传特征表明这是其主要的繁殖方式，尽管偶尔也会产生雄性个体。与之形成对比的是，位于大陆最北端的得克萨斯种群呈现出有性生殖的遗传特征，且个体无法通过产雌孤雌生殖完成繁殖。与地理孤雌生殖分布格局的预期相悖，多数大陆种群被发现为兼性产雌孤雌生殖，兼具有性生殖与孤雌生殖的种群遗传特征。