Floral function: effects of traits on pollinators, male and female pollination success, and female fitness across three species of milkweeds (Asclepias)

Abstract

Traits tended to function in only one sex, and more traits affected function through pollinator efficiency than through attraction. There was no significant link between female pollination success and female fitness in any of the three species; this pattern is consistent with fruit production not being limited by pollen deposition.

Learning in two butterfly species when using flowers of the tropical milkweed Asclepias curassavica: No benefits for pollination

“…There is no information about pollinium dispersal of A. curassavica by D. erippus and H. erato . Flower display, as well as horn and hood size variation, can influence attraction of floral visitors and pollination efficiency of some species of Asclepias (La Rosa and Conner, 2017). We have demonstrated that the larger the inflorescence of A. curassavica , the higher the number of removed and inserted pollinia.…”

Convergent evolution of floral shape tied to pollinator shifts in Iochrominae (Solanaceae)*

“…Shape variation may also influence the interaction between the pollinator and the floral reproductive organs, leading to associated variation in pollen deposition or removal. This link between flower shape and pollinator efficiency has well-documented consequences for both male and female components of fitness (e.g., Campbell et al 1996;Kulbaba and Worley 2013;La Rosa and Conner 2017). Importantly in the context of the pollinator-shift model, different pollinators often exert different selective pressures on flower shape (Campbell 2004;Muchhala 2007;Gomez et al 2008), suggesting that shifts among pollinators, whether within a single species or across a clade, will lead to corresponding shifts in multiple aspects of shape.…”

“…This link between flower shape and pollinator efficiency has well‐documented consequences for both male and female components of fitness (e.g., Campbell et al. ; Kulbaba and Worley ; La Rosa and Conner ). Importantly in the context of the pollinator‐shift model, different pollinators often exert different selective pressures on flower shape (Campbell ; Muchhala ; Gomez et al.…”

Untitled

“…This usually allows a single successful pollination event to fertilize all of the ovules in an ovary, resulting in full-sibling families in each fruit (Sparrow and Pearson, 1948;Wyatt and Broyles, 1990). These features have positioned Asclepias as a model in studies of angiosperm reproductive biology (Broyles and Wyatt, 1990;Broyles, 1990, 1994), floral development (Endress, 2006(Endress, , 2015, selection on floral characters and prezygotic reproductive isolation (La Rosa and Conner, 2017;Morgan and Schoen, 1997), and floral display evolution (Chaplin and Walker, 1982;Fishbein and Venable, 1996; Willson and Rathcke, 1974).…”