Conflicting selection on floral traits

Floral traits attracting pollinators may also attract seed predators; however, evidence for conflicting selection on such traits remains scarce. One could expect that such selection generated by pollinators and seed predators varies geographically.

Pedicularis rex
Measurements of six floral and six vegetative traits in Pedicularis rex. FL, flower length; TL, tube length; TD, tube diameter; LLL, lower lip length; LLW, lower lip width; CO, corolla opening; SD, stem diameter; LL, leaf length; LW, leaf width; WTC, width of top of cupular bract; WBC, width of bottom of cupular bract; CBH, cupular bract height. Arrows show water in the cupular bract. Image: Sun et al. (2016)

Examining multiple populations across a geographic mosaic of environments and floral variation, Sun et al. investigate female reproductive success in a bumblebee-pollinated subalpine herb, Pedicularis rex, in which tubular flowers are subtended by cupular bracts holding rain water. They found that plants experienced conflicting selection: those with flowers that were more exserted beyond the water-holding bracts were better pollinated, but also suffered more seed predation.

Reference List

Shi-Guo Sun, W. Scott Armbruster, Shuang-Quan Huang, 2016, 'Geographic consistency and variation in conflicting selection generated by pollinators and seed predators', Annals of Botany, vol. 118, no. 2, pp. 227-237