Regional flower visitor assemblages and divergence of floral traits of the baobab Adansonia digitata (Malvaceae) across Africa

Abstract Regional differences in flower visitor assemblages can lead to divergence of floral traits in plants. We investigated variation in floral traits and flower visitors across the distribution range of the African baobab, Adansonia digitata, focusing on populations in southern Africa, east Africa, and west Africa. We enumerated flower visitors by using camera traps, direct observations, and mist netting of bats. We compared floral morphology, nectar traits, and scent chemistry across the three regions. We found that floral traits, notably flower shape and scent chemistry, are highly divergent geographically and match the foraging behaviour, size, and known olfactory preferences of the most important flower visitors in each region. The bats Eidolon helvum and Rousettus aegyptiacus were the main flower visitors in west and east Africa, respectively, and we confirmed that flowers in southern Africa are not visited by bats. Moths, particularly hawkmoths, were frequent flower visitors in all regions. These results indicate that Adansonia digitata has diverged in floral phenotype across its distribution range, possibly in response to regional flower visitor assemblages.