Termites became the dominant decomposers of the tropics after two diversification pulses

In modern tropical ecosystems, termites are the dominant non-microbial decomposers. However, the timing and drivers of their rise remain unclear. To investigate termite diversification over the past 130 million years, we reconstructed the most comprehensive time-calibrated phylogeny to date by sampling more than 1,300 species (∼47% of described diversity). Our diversification analyses revealed two major pulses. The first occurred in the Late Cretaceous period and marked the initial radiation of Kalotermitidae, followed by the early radiation of Neoisoptera as the diversification of Kalotermitidae slowed down. The second, stronger pulse followed the Eocene-Oligocene transition and extended into the Miocene. This phase coincided with global cooling, rainforest contraction, and savanna expansion. It involved repeated diversification within the Termitidae family and was accompanied by extensive transoceanic dispersal, which led to the global spread of Neoisoptera and the formation of modern tropical termite communities. Together, our results suggest that climate-driven biome turnover and global dispersal, rather than plant innovation, underpinned the rise of termites as dominant tropical decomposers.