Aim: Understanding how climate conditions influence plant–pollinator interactions at the global scale is crucial to understand how pollinator communities and ecosystem function respond to environmental change. Here, we investigate whether climate drives differences in network roles of the main insect pollinator orders: Diptera, Coleoptera, Lepidoptera and Hymenoptera.

Location: Global.

Time period: 1968–2020.

Major taxa studied: Diptera, Coleoptera, Lepidoptera and Hymenoptera.

Methods: We collated plant–pollinator networks from 26 countries and territories across the five main Köppen–Geiger climate zones. In total, we compiled data from 101 networks that included >1500 plant species from 167 families and >2800 pollinator species from 163 families. We assessed differences in the composition of plant–pollinator interactions among climate zones using a permutational ANOVA. We calculated standard network metrics for pollinator taxonomic groups and used Bayesian generalized mixed models to test whether climate zone influenced the proportion of pollinator network links and the level of pollinator generalism.

Results: We found that climate is a strong driver of compositional dissimilarities between plant–pollinator interactions. Relative to other taxa, bees and flies made up the greatest proportion of network links across climate zones. When network size was accounted for, bees were the most generalist pollinator group in the tropics, whereas non-bee Hymenoptera were the most generalist in arid zones, and syrphid flies were the most generalist in polar networks.

Main conclusions: We provide empirical evidence at the global scale that climate strongly influences the roles of different pollinator taxa within networks. Importantly, non-bee taxa, particularly flies, play central network roles across most climate zones, despite often being overlooked in pollination research and conservation. Our results identify the need for greater understanding of how global environmental change affects plant–pollinator interactions.

1. Globally, plants display enormous variation in life-history strategies and trait combinations. However, evidence suggests that evolutionary and physiological constraints limit the number of plant ecological strategies. Although there have been recent advances in understanding correlations among plant traits, reproductive traits are rarely considered, despite their key role in shaping plant life-history strategies and interactions with pollinators.
2. Here, using a global dataset of 18 reproductive traits for 1506 species, we investigate the reproductive spectrum of flowering plants to identify how it shapes interactions with pollinators.
3. We show that over 50% of all trait variation is explained by the first two reproductive axes, which represent the negative correlation between flower number and flower size, and the negative correlation between autonomous selfing and floral display size. In addition, these reproductive axes were associated with the identity and number of visits of the distinct pollinator guilds. However, reproductive axes explain a relatively small amount of variance in pollinator interactions highlighting the need to incorporate other factors along with reproductive traits to fully explain large-scale patterns of plant-pollinator interactions.
4. Our study identifies the major reproductive trait correlations in flowering plants and their role in shaping plant-pollinator interactions at a macro-ecological scale. These findings emphasise the importance of considering reproductive traits in the global spectrum of plant form and function, and the need to explore beyond floral morphological traits to broaden our understanding of plant-pollinator interactions.