Kris Peach just published a paper in Ecology and Evolution!
Sex-specific floral attraction traits in a sequentially hermaphroditic species
Ecology and Evolution: DOI: 10.1002/ece3.5987
● Many angiosperms are hermaphroditic and produce bisexual flowers in which male
(pollen export) and female (stigma receptivity) functions are separated temporally.
This sequential hermaphroditism may be associated with variation in flower size,
color, or pattern, all of which may influence pollinator attraction. In this study, we
describe variation in these traits across discrete functional sex stages within and
between 225 greenhouse-grown individuals of Clarkia unguiculata (Onagraceae).
In addition, to identify the effects of floral phenotype on pollinator attraction in
this species, we examine the effects of these floral traits on pollen receipt in ~180
individuals in an experimental field array.
● Petal area, ultraviolet (UV)-absorbing nectar guide area, and blue and green mean
petal reflectance differ significantly across the functional sex stages of C. unguiculata.
Male- and female-phase flowers display significantly different pollinator attraction
traits. Petal and UV nectar guide area increase as flowers progress from
male phase to female phase, while blue reflectance and green reflectance peak
during anther maturation.
● In field arrays of C. unguiculata, female-phase flowers with large UV nectar guides
receive more pollen than those with small nectar guides, and female-phase flowers
with high mean blue reflectance values are more likely to receive pollen than
those with low blue reflectance. Female-phase flowers with green mean reflectance
values that differ most from background foliage also receive more pollen
than those that are more similar to foliage. These findings indicate that components
of flower color and pattern influence pollen receipt, independent of other
plant attributes that may covary with floral traits. We discuss these results in the
context of hypotheses that have been proposed to explain sex-specific floral attraction
traits, and we suggest future research that could improve our understanding
of sexual dimorphism in sequentially hermaphroditic species and the evolution
of features that promote outcrossing.