Studies which have traced the evolution of floral traits using phylogenies of particular plant groups suggest that shifts between different pollinators, rather than coevolution with them, has been the main driver of diversification.
For well studied plant species, however, only a few different pollinators are reported and these pollinator species are rather unspecialized, being found pollinating several plant genera or families [ 27, 72, 74].
The above studies underscore the importance of understanding how often fitness trade-offs between floral adaptations to different pollinators occur, not least because floral specialization is promoted by the fitness trade-offs between pollinators (e.g. Schemske and Horvitz 1984; Wilson and Thomson 1996; Aigner 2001; Mayfield et al. 2001; cf. Muchhala et al. 2010).
In contrast 49 pollinators are observed both years with 79 different pollinators in total.
Kessler, Baldwin and colleagues address this issue, perhaps in an unforeseen way, by testing three different pollinators of coyote tobacco.
This shift in resources could result in different pollinator abundances, species richness and trait compositions between seasons, as well as in how these components are spatially distributed.
A larger idea that provided the impetus for the module was that different species of the same plant have evolved different pollinator syndromes such that coevolution has occurred between plants and the species that pollinate them.
Each of these sets of nodes, A and B, may represent different pollinator types.
