Project

Clade proliferation and pollinator use in Pelargonium (Geraniaceae)

Pelargonium species, mostly from S African Cape Floristic Region, exhibit a wide range of both floral and vegetative variation. Floral variation probably reflects pollinator use, enabling testing hypotheses on trait-dependent clade proliferation: is speciation rate change dependent on pollinator switches?

Project description

Using a phylogenetic tree for the genus, we can trace the evolution of the nectar tube length for almost all 280 species and infer ancestral states for this character. Subsequently, trends in tube length evolution, probably reflecting a switch in use of pollinator, can be correlated with clade-size by using QUASSE modelling. In this way we can address the question whether speciation rate may be drive by switches in pollinator use?

Results

So far we inferred that overall and trend exists in Pelargonium towards longer nectar tubes -implying some degree of pollinator filtering’, and that the longest tubes -implying specialization on specific pollinators- results in small clades, i.e. low speciation rates.