Wang Xiaoyue ^1,2 Han-Qing Tang ^1,3 Yun-Jing Liu ^1,2 Meng-Da Xiang ^1,2 Ren-Xiu Yao ^1,2 Bai-Zhu Li ^1,2 Yu Li ^1,2 Yin Yi ^1,2 Zhi-Rui Wen ^1,4 Ming Tang ^1,2* Xiaoxin Tang ^1,5*

• ¹ Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, School of Life Science, Guizhou Normal University, Guiyang, China
• ² Engineering Research Center of Carbon Neutrality in Karst Areas, Guizhou Normal University, Guiyang, Guizhou Province 550001, China, Guiyang, Guizhou Province, China
• ³ School of Resources and Environmental Science, Hubei University, Wuhan 430062, China, wuhan, China
• ⁴ Guizhou Collaborative Innovation Center of Green Finance and Ecological Environment Protection, Guiyang 550025, China, Guiyang, Guizhou Province, China
• ⁵ School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 50 Nanyang Avenue 639798, Singapore, Singapore

Flower color polymorphism is often attributed to selection pressures from pollinators or other non-pollinator stress factors. Generally, flower color polymorphism demonstrates effective acclimatization linked to either pollinator-mediated selection or pleiotropic effects. To test these hypotheses in Ophiorrhiza japonica, we compared pollinator visitation frequencies and plant traits between pink and white morphs in Shibing, a dolomite Karst region recognized as a World Natural Heritage Site. We also assessed the ratio of flower morphs and the reproductive success of the two morphs during spring and winter. Additionally, we examined the effects of temperature shifts on the two morphs under various temperature treatments.Our results revealed no significant difference in visitation frequencies between the morphs. However, the ratio of pink to white morph differed significantly between spring and winter. The temperature of pink morph was higher than that of white morph at temperatures ranging from 0-24°C, while white morph had higher temperatures than pink morph at -4°C. Based on the aforementioned results, pollinators are not the primary factor influencing the distribution of flower colors in spring and winter. Furthermore, the response of different flower colors to temperature suggests that temperature is more likely the factor driving changes in flower coloration. Our study provides further evidence supporting the pleiotropic effect hypothesis, which posits that flower color polymorphism can be maintained by fluctuating temperatures in the dolomite Karst region. This study offers a potential model for explaining flower color polymorphism in Karst regions.