Why does this matter? Climate change can alter where species occur and when plants flower or pollinators are active. We did not test future changes directly, but our results suggest that pollination networks will not all respond in the same way. 8/8

The strongest common thread was climate. Temperature and rainfall were generally better-supported predictors of specialisation than latitude, biodiversity or ecosystem productivity. Yet their effects were nonlinear and differed greatly among pollinator groups. 7/8

Nor was there one pattern for all pollinators. Bees, hoverflies, butterflies, moths and birds showed distinct geographical trends, often with several local peaks and dips. Lumping them together would hide much of this ecological variation. 6/8

The classic expectations were not supported. Specialisation neither consistently increase towards the Equator, nor towards the poles. Network-level and pollinator specialisation often peaked around 20–30° N, near the tropical–subtropical boundary. 5/8

Besides the data size, we treated limits of previous studies: controlled sampling completeness, separated community-wide networks from group-focused ones, and analysed plants and pollinator groups separately. This distinguished broad trends from group-specific responses. 4/8

To test this, we compiled 3,415 quantitative networks with >110,000 links among 5,343 pollinator and 6,126 plant species across all major terrestrial biomes. The study brought together 142 researchers from 32 countries. 3/8

Specialisation is an evolutionary bargain. A close match can make feeding and pollen transfer highly efficient, but it also creates dependence on particular partners. Ecologists have long expected such close relationships to be especially common in the tropics. 2/8