Data from: Honey bees are the most abundant visitors to Australian watermelon but native stingless bees are equally effective as pollinators

Despite the benefits of a diverse approach to crop pollination, global food production remains reliant on a low diversity of managed pollinators, especially the European honey bee (Apis mellifera). To facilitate more robust pollinator management and improve the resilience of the production system, it is necessary to understand regional variation in the pollination ecology of global food crops. Watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) is a highly insect pollinator-dependent crop and even though it is grown globally across many different climate zones, little is known about its pollination ecology across the diverse growing regions of Australia, spanning from the tropics to the arid zone. We compared the species composition, visitation rates, and effectiveness of the dominant floral visitors on 15 farms across five major watermelon-growing regions of Australia. We found that insect species composition differed significantly among regions, but honey bees were the dominant watermelon flower visitor, with relative abundance varying from 73 - 94%. However, native bees (including stingless bees Tetragonula sp., and bees from Families Megachilidae, and Halictidae such as Lasioglossum, Homalictus, Lipotriches), and flies (particularly Syrphidae sp.) also visited and transferred pollen onto watermelon flowers. In particular, native stingless bees were common visitors in several growing regions and deposited similar amounts of pollen to honey bees. Our findings indicate that the Australian watermelon industry utilizes honey bees, but the diverse assemblage of available native pollinating taxa provides an additional opportunity for growers in specific growing regions. These native taxa may be encouraged in the production system by deploying managed populations (e.g. native stingless bee colonies), employing pollinator-safe land management practices, as well as exploring methods for increasing the efficiency of managed honey bee colonies.

尽管多样化的作物授粉策略具备诸多优势，但全球粮食生产仍高度依赖种类有限的管理授粉昆虫（managed pollinators），尤以西方蜜蜂（Apis mellifera）为核心依赖对象。为实现更稳健的授粉昆虫管理、提升生产系统的抗逆韧性，亟需厘清全球粮食作物授粉生态学的区域异质性。西瓜（Citrullus lanatus (Thunb.) Matsum. & Nakai）是一类高度依赖昆虫授粉的作物，尽管其在全球多个气候带均有规模化种植，但针对澳大利亚从热带至干旱区的多样种植区域内的西瓜授粉生态学，目前仍缺乏系统认知。我们针对澳大利亚五大主要西瓜种植区的15个农场开展了田间调查，对比了该区域内主要访花昆虫（floral visitors）的物种组成、访花频率及授粉效力。研究结果显示，不同区域的昆虫物种组成存在显著差异，而西方蜜蜂仍是西瓜花的优势访花者，其相对丰度介于73%至94%之间。不过，本土蜂类（包括无刺蜂属（Tetragonula sp.）类群、切叶蜂科（Megachilidae）及隧蜂科（Halictidae）的Lasioglossum、Homalictus、Lipotriches等类群）以及蝇类（尤以食蚜蝇科（Syrphidae sp.）为代表）同样会访花并为西瓜花传递花粉。尤为关键的是，本土无刺蜂在多个种植区域均为常见访花者，其沉积的花粉量与西方蜜蜂并无显著差异。本研究表明，澳大利亚西瓜产业当前主要依赖西方蜜蜂开展授粉，但各特定种植区域内丰富的本土授粉类群，为种植者提供了额外的授粉优化途径。通过部署管理种群（如本土无刺蜂蜂群）、采用对授粉昆虫友好的土地管理措施，以及探索提升管理西方蜜蜂蜂群效率的可行方法，即可在生产系统中培育并利用这些本土授粉类群。