DOI: 10.5061/dryad.crjdfn3b1
title: Red fruits exhibit lower colour diversity than red flowers as perceived by birds

description: Pollination and seed dispersal are crucial processes for plant
 reproduction, sharing ecological relevance and similarities, yet they have
 rarely been considered together. Flowers appear to express greater
 phenotypic diversity than fruits due to multiple confounding factors,
 which pose challenges for comparative analyses. The colours of flowers and
 fruits are important visual signal traits in pollination and seed
 dispersal, evolving under different selective pressures from their
 respective pollinators and seed dispersers. Birds constitute a unique
 plant-interacting group that participates in both pollination and seed
 dispersal events. In this study, we focus on red flowers and red fruits
 associated with avian mutualists to gain insight into the intrinsic
 differences between flowers/pollination and fruits/seed dispersal. We
 conducted comparisons of colouration between 94 red flowers pollinated by
 birds and 99 red fruits dispersed by birds. The colour diversity was
 compared in both the spectral space and the avian colour vision spaces.
 Colour conspicuousness was analyzed using avian colour vision models, as
 well as bee models. Pigeon colour preference was tested by controlled
 experiments utilizing red stimuli with and without secondary peaks at
 short wavelengths. Red fruits had lower colour diversity than red flowers,
 with redder hues and fewer secondary reflectance peaks. Avian colour
 vision models illustrated that fruits were more conspicuous than flowers
 achromatically, but not chromatically. Pigeons did not show preference for
 red with or without a secondary peak. Although both are red, there are
 significant differences between flowers and fruits in terms of colour
 diversity, spectral properties and colour perceptions. As we exclusively
 considered avian mutualists, these differences cannot be attributed to the
 differences in interacting animal groups or to their colour vision
 properties. This implies that the differences in evolutionary history
 between flowers and fruits may deserve further attention to understand the
 colour evolution.
description: Spectral reflectance was
 measured by a spectrometer (USB 2000+, Ocean Optics) equipped with a
 UV-VIS light source (DH2000, Ocean Optics) and a white standard
 polytetrafluoroethylene (PTFE). The fibre-optic probe was fixed on the
 holder at 45°. At least three samples of different plant individuals were
 measured. Records between 300 and 700 nm were averaged and finally
 used.
description: # Red fruits exhibit lower colour diversity than red flowers as perceived
 by birds
 [https://doi.org/10.5061/dryad.crjdfn3b1](https://doi.org/10.5061/dryad.crjdfn3b1) The spectral reflectance we collected for this study. There are 94 spectra (12 for red flowers and 82 for red fruits), which were used to analyze colour properties, and animal perception. ## Description of the data and file structure There are 94 species, whose details can be found in the Supporting Information Table S2. The first column in this file are wavelengths from 300 to 700 nm, and the other columns are spectra of the 94 species. ## Sharing/Access information ## Code/Software Analyses on the spectral data were conducted in R, and package *pavo* was used.