Variability in style deflexion and its fitness consequences

Variability of floral traits within individuals is usually regarded as developmental noise and not considered in studies of adaptive evolution.

Passiflora incarnata
Passiflora incarnata. Photo Maggie McCain / Flickr.

Dai et al. measure style deflexion, a floral trait in Passiflora incarnata responsible for herkogamy and pollen deposition. They find that the degree of style deflexion varies within and among flowers, and different plants show different levels of variability. Acting through pollen deposition, reduced variability of style deflexion increased seed number but decreased seed weight. Opposing effects of variability in style deflexion on different fitness components may contribute to the diversity of style phenotypes found in passion flower.

Further reading

Can Dai, Xijian Liang, Jie Ren, Minglin Liao, Jiyang Li, Laura F. Galloway, 2016, 'The mean and variability of a floral trait have opposing effects on fitness traits', Annals of Botany, vol. 117, no. 3, pp. 421-429