Question

The authors state that M. cardinalis evolved “from an insect-pollinated ancestor likely to have resembled the extant M. lewisii.” Given this statement, briefly describe what this experiment tells us about the impacts of this allele on prezygotic reproductive isolation between these two species of wildflower. (Just a few sentences, nothing fancy!)

Answer 1

Pollinated mediated selection on floral traits is widely regarded as a common mechanism of adaptation and speciation in plants. Besides their morphological differences , these two monkey flowers are closely related. The experiment stated concluded that M.lewisi was visited primarily by bees and M.cardinalis was visited by hummingbird so experimental plot shows same result as such natural selection. F1 hybrids indicating strong genetic components whereas F2 hybrids results varies. These results provide clear evidence that flower colour contribute reproduction isolation despite to the recent statements contrary.

Adaptation to different pollinators may involve genes with large phenotypic effects by comparing QTL markers, that two traits with the greatest impacts on bee and hummingbird visitation. Plants homozygous for the M.cardinalis allele had twice the rate of hummingbird visitation as M.lewisi homozygouts whereas heterozygotes has an intermediate value. This work contributes to the growing body of evidence that adaptation often may involve alleles of large effects.