Plants with specialized pollination systems may be susceptible to reproductive failure when pollinator service is unpredictable. This can influence the selection of floral traits that promote outcrossing in the presence of pollinators and selfing in their absence. Limited evidence exists regarding the association between specialized pollination and reproductive assurance, necessitating further investigation. We studied the reproductive biology of Dianthus inoxianus, a rare Mediterranean carnation endemic to a semi-arid region in SW Spain. D. inoxianus exhibited protandrus flowers and additional phenotypic signs of specialization for nocturnal pollination. Nectar sugar concentration remains relatively constant throughout the day (average 33.4%), while the standing crop varies considerably (average 1.5 μL/flower), peaking in the late afternoon and early evening. Controlled hand pollinations revealed that D. inoxianus is fully self-compatible, with similar reproductive success in autogamous, geitonogamous, and allogamous crosses. However, a small proportion of bagged flowers exhibited autonomous selfing. To assess the impact of presumed nocturnal pollination, we studied reproductive fitness and flower visitors over five years in three populations. Over 210 h of pollinator censuses, the hawkmoth species Hyles livornica and Macroglossum stellatarum, which were mainly dusk-active, accounted for > 95% of flower visits. Fruit and seed set positively correlated with hawkmoth visitation rate across years and populations. Additionally, pollinator exclusion experiments demonstrated that reproduction relies predominantly on nocturnal pollinators. However, under natural conditions, D. inoxianus also showed a non-negligible degree of autonomous self-pollination, with fruit- and seed-set being equivalent in absence of pollinators or under diurnal pollinators. We found evidence of an ecologically specialized pollination system and capacity for autonomous selfing, a combination that may enable the persistence of this taxon in a markedly unpredictable pollination environment.

当授粉媒介服务不可预测时，具有专门授粉系统的植物可能容易出现繁殖失败。这可能会影响花性状的选择，这些性状在传粉媒介存在时促进异交，在传粉媒介不存在时促进自交。关于专门授粉和繁殖保证之间关系的证据有限，需要进一步调查。我们研究了石竹（Dianthus inoxianus）的繁殖生物学，石竹是西班牙西南部半干旱地区特有的稀有地中海康乃馨。D. inoxianus表现出原雄花和夜间授粉专门化的其他表型特征。花蜜糖浓度全天保持相对恒定（平均 33.4%），而直立作物变化很大（平均 1.5 μL/花），在下午晚些时候和傍晚早些时候达到峰值。受控的手工授粉表明，D. inoxianus是完全自交亲和的，在自花受精、同卵受精和异体受精杂交中具有相似的繁殖成功率。然而，一小部分袋装花卉表现出自主自交。为了评估假定的夜间授粉的影响，我们研究了三个种群五年来的生殖健康和花客。在超过 210 小时的授粉昆虫普查中，主要在黄昏活动的天蛾品种Hyles livornica和Macroglossum stellatarum占花访问量的 95% 以上。果实和种子的结实与不同年份和不同种群天蛾的访问率呈正相关。此外，传粉媒介排除实验表明，繁殖主要依赖于夜间传粉媒介。然而，在自然条件下，D. inoxianus也表现出不可忽视的自主自花授粉程度，在没有授粉媒介或在昼间授粉媒介的情况下，其坐果和结籽效果相同。我们发现了生态上专门的授粉系统和自主自交能力的证据，这种组合可能使该分类群能够在明显不可预测的授粉环境中持续存在。