Abstract Fruit size is a key functional trait influencing seed dispersal, seedling survival, and species establishment. Its variation and drivers are of broad interest in the fields of evolutionary biology and ecology. The pantropic family Lauraceae plays a vital role in the evergreen broad-leaved forests in East Asia, yet the diversity patterns of fruit size of this family and their determinants remain unclear. In this study, we compiled and integrated a trait dataset including fruit size, species occurrences, environmental variables, and DNA markers of the Lauraceae throughout East Asia to investigate the temporal and spatial patterns of fruit size and their determinants. The results indicate that fruit size in the Lauraceae decreases with increasing latitude and is negatively related to species distribution area (P .001). It is positively correlated with mean temperature of the coldest quarter, isothermality, and potential evapotranspiration, but negatively correlated with temperature annual range. Our phylogenomic and ancestral state reconstruction analyses show that the evolution of fruit size in the Lauraceae is constrained by phylogeny, with medium-sized fruits in all likelihood being the ancestral state. Further variance partitioning analysis reveals that environmental factors and phylogeny jointly explain 63.1% of the variation in fruit size, while the remaining 36.9% is unresolved. Our study reveals the diversity patterns of fruit size of the Lauraceae in East Asia and identifies the determinants of fruit size variation in the family, thus providing a new window to better understand the macroevolution of the family.
Ye et al. (2026) studied this question.