Global analysis of floral longevity reveals latitudinal gradients and biotic and abiotic correlates

The length of time a flower remains open and functional – floral longevity
– governs important reproductive processes influencing pollination and
mating and varies considerably among angiosperm species. However, little
is known about large-scale biogeographic patterns and the correlates of
floral longevity. Using published data on floral longevity from 818
angiosperm species in 134 families and 472 locations worldwide, we present
the first global quantification of the latitudinal pattern of floral
longevity and the relationships between floral longevity and a range of
biotic and abiotic factors. Floral longevity exhibited a significant
phylogenetic signal, and was longer at higher latitudes in both northern
and southern hemispheres, even after accounting for elevation. This
latitudinal variation was associated with several biotic and abiotic
variables. The mean temperature of the flowering season had the highest
predictive power for floral longevity, followed by pollen number per
flower. Surprisingly, compatibility status, flower size, pollination mode,
and growth form had no significant effects on flower longevity. Our
results suggest that physiological processes associated with floral
maintenance play a key role in explaining latitudinal variation in floral
longevity across global ecosystems, with potential implications for floral
longevity under global climate change and species distributions.