Data from: Flower signal variability overwhelms receptor-noise and requires plastic color learning in bees

Color discrimination thresholds proposed by receptor-noise type models are
frequently used in animal vision studies to predict a precise limit on the
capacity of an animal to discriminate between stimuli. Honeybees and
bumblebees are two closely related hymenopteran species for which precise
data on photoreceptor sensitivities and receptor noise exist, enabling
accurate testing on how their vision conforms to model predictions. Color
vision has been proven in these species, and they are known to
predominantly visit flowers using visual signals to collect nutrition.
Surprisingly, however, the natural variability of flower signals has been
rarely considered, and recent work also suggests bees may tune color
vision through experience. We initially measured the spectral variability
of flowers from two species: Goodenia ovata and Rosemarinus officinalis
where free-flying honeybees were observed constantly foraging from
conspecific flowers. We empirically determined honeybee color
discrimination thresholds for color stimuli considering either absolute-
or differential-conditioning discrimination functions. Secondly, we
analyzed greenhouse grown wild type Antirrhinum majus flower petal spectra
as well as spectra from mixta and nivea strains of this species, and
empirically determined bumblebee color discrimination considering
conditioning experience. In all measured cases within-flower type spectral
variability exceeded a 1.0 Receptor Noise threshold, often by several
units. Observed behavioral color discrimination functions considering the
respective conditioning procedures closely matched the range of signal
variability for both honeybees and bumblebees, showing that color vision
in bees cannot be described by a single fixed value, and plasticity is a
key component of bee foraging behavior in natural environments.