Floral disparity of the sensitive plants: the role of integration, modularity and pollinators in the diversity of Mimosa flowers

Abstract

The high diversity in the reproductive structures of angiosperms is associated with different factors, from changes in floral development to pressures caused by ecological interactions. In particular, changes in floral form and function are often attributed to changes in the pollination system, which can also drive diversification processes. However, some groups of plants have an apparent conservation of floral morphology, despite the high taxonomic diversity in environments full of ecological opportunities. In this study we propose to connect patterns of disparity, phenotypic integration and modularity, and plant-pollinator interactions to investigate the floral morphological evolution of Mimosa (Leguminosae), a highly diverse genus, but with apparently uniform floral morphology. We intend to answer the following questions: (1) What is the degree of morphological diversity of floral structures? (2) Is the degree of floral disparity influenced by integration and/or floral modularity patterns? (3) Are patterns of disparity, integration and floral modularity related to interactions with pollinators? To answer these questions, we will compile data on the floral morphology of Mimosa species, covering their phylogenetic and geographic diversity. With these data, we will calculate size, density and position of species in a morphospace, estimate the magnitude of floral integration and test whether developmental and functional patterns affect floral modularity. Furthermore, we will investigate whether variations in disparity, integration and floral modularity are related to plant-pollinator interactions through the functional diversity of pollinators and ecological network metrics. With this, we hope to understand if and how the floral morphology of Mimosa was shaped by morphological limitations and biological interactions and also to provide new perspectives on processes that drive the evolution of floral disparity. (AU)