Department of Natural Sciences, Semi-Arid Biodiversity Laboratory - Labisa, State University of Southwest Bahia, Estrada do Bem Querer, Km 04, UESB, 45031-900 Vitoria da Conquista, BA, Brazil.
Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil; Department of Genetics, Graduate Program in Genetics, Ribeirão Preto Medical School, University of São Paulo, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil.
Sci Total Environ. 2022 Apr 15;817:152982. doi: 10.1016/j.scitotenv.2022.152982. Epub 2022 Jan 11.
The reproductive success of a zoophilous plant species depends on biological interaction with pollinators, which involves both the provision and exploitation of flower resources. Currently, there is little information about how future climate change scenarios will impact interactions between plants and their flower visitors in the tropics. This study analyzes the effects of warming and two soil water conditions on interactions between the tropical forage legume species Stylosanthes capitata and its floral visitors during the flowering period. We used a temperature-free air-controlled enhancement (T-FACE) facility to simulate future warming scenarios by increasing canopy temperature. The tested treatments were: irrigated and ambient canopy temperature (Control); non-irrigated and ambient canopy temperature (wS); irrigated and elevated canopy temperature (eT, +2 °C above ambient canopy temperature); and non-irrigated and elevated canopy temperature (wSeT). The effects of treatments on the time of flower opening and closing, sugar concentration in the nectar, and plant-flower visitor interactions were assessed. In the warmed treatments, S. capitata flower opening occurred ~45 min earlier compared to non-warmed treatments, and flowers remained opened for only ~3 h. Further, the sugar concentration in the nectar from eT was 39% higher than in the Control. The effects of warming on floral biology and flower resource production in S. capitata had an impact on the plant-floral visitor relationships with the bees Apis mellifera and Paratrigona lineata, the most abundant potential pollinating floral visitors, and the butterfly visitor Hemiargus hanno. Additionally, around noon, the interactive and additive effects of the combined wS and eT treatments decreased insect visiting frequency. These results suggest that warming and soil water deficiency could affect flower-visitor interactions and thus the reproductive success of S. capitata in tropical belts.
热带地区植物与传粉者之间的相互作用受未来气候变化情景的影响较小。本研究分析了增温和两种土壤水分条件对热带豆科牧草弯叶山蚂蝗开花期与访花昆虫相互作用的影响。我们使用温度自由空气控制增强（T-FACE）设施，通过增加冠层温度来模拟未来的升温情景。测试的处理方法有：灌溉和环境冠层温度（对照）；非灌溉和环境冠层温度（wS）；灌溉和升高的冠层温度（eT，比环境冠层温度升高 2°C）；非灌溉和升高的冠层温度（wSeT）。评估了处理方法对花开放和关闭时间、花蜜中糖浓度以及植物-花访客相互作用的影响。在升温处理中，S. capitata 花的开放时间比非升温处理提前约 45 分钟，而花只开放约 3 小时。此外，eT 花蜜中的糖浓度比对照高 39%。升温对 S. capitata 花生物学和花资源生产的影响，对蜜蜂 Apis mellifera 和 Paratrigona lineata 这两种最丰富的潜在传粉者与蝴蝶访客 Hemiargus hanno 与植物-花访客关系产生了影响。此外，在中午左右，wS 和 eT 联合处理的交互和附加效应降低了昆虫的访问频率。这些结果表明，升温和土壤水分亏缺可能会影响花-访客相互作用，从而影响热带地区 S. capitata 的繁殖成功。
