Data from: Sex-limited diversification of the eye in Heliconius butterflies
Abstract
Butterflies have evolved an immense diversity in eye organization to support a range of vision-based behaviors, including courtship, oviposition, and foraging. This diversity has been surveyed extensively across the butterfly phylogeny, and here we take a complementary approach to characterize the eye within a group of closely related Heliconius butterflies. Using a combination of immunostaining for different opsins and eyeshine for determining the distribution of light-filtering screening pigments, we identified several sexually dimorphic features of eye organization where male eyes varied and female eyes did not. Ultraviolet (UV) sensitive photoreceptors varied in which of two UV opsins were expressed, including co-expression of both within single photoreceptors, and these differences were consistent with a role in courtship and conspecific identification. Additional differences across species and sex included the distribution of three ommatidial types defined by the expression pattern of UV and blue opsins, the distribution of screening pigments, and the relationship between ommatidial type and screening pigment. We hypothesize that female eyes are optimized for a dimorphic behavior such as oviposition, while male eyes more freely adapt to their natural light environment.
Dataset DOI: 10.5061/dryad.5hqbzkh7v
Description of the data and file structure
We used a combination of epifluorescent microscopy to examine eyeshine and opsin immunohistochemistry to characterize the organization of the eye in a closely related group of Heliconius cydno butterflies.
Files and variables
File: data.zip
Description: This zip file includes all data necessary to reproduce analyses completed in the manucript. It includes two folders and two .mat files.
Folder 1: images
This folder includes the original .czi files for all confocal images used for immunohistochemistry against UV1, UV2, and blue opsins.
Folder 2: immunostaining images
This folder includes the processed version of the confocal images used for all analyses.
Within this folder there is first a set of folders with names indicating butterfly ID. These additionally
include folders indicating which eye and which slice was used.
Finally, within these folders:
.czi file is the orginal image
uv1, uv2, and blue are the processed images for single channels on the image.
Merged is uv1, uv2, and blue together, with uv1 and uv2 combined together as a single color representing UV
Cropped is a cropped version of merged that was used for analysis.
Binary images are the single channels turned into a binary mask that was used for analysis and identifying ommatidia and their expression patterns. See manuscript methods for details.
File 1: eyeshine.mat
This includes all data used for analysis of the eyeshine images.
It includes the variables:
id - identifier for all butterflies used in the study
labels - taxon label for each row in the id variable
femaleType - species id for each female (row 7) in id variable
photos - each cell corresponds to the butterfly in id variable. Within each cell is a vector of cells, each of which is an original eyeshine image going from the dorsal eye to the ventral eye.
count - each cell corresponds to the butterfly in the id variable. Within each cell, values represent the total number of yellow ommatidia (column 1) and red (column 2) ommatidia in each of the images.
File 2: immunostaining.mat
This includes all data used for analysis of immunostaining.
It includes the variables:
butterflies - list of all butterfly IDs
clusteredImage - Each cell corresponds to the butterfly in butterflies variable. Within each cell, each cell corresponds to an image of a different slice of the same eye. Colors indicate ommatidia that are UV-UV (purple), B-B (blue), or UV-B (white).
ommatidia - same organization as clusteredImage, but final nested matrix has every identified ommatidium as a row. Column 1 is UV opsin expression, and column 2 is blue opsin expression. A value of 1 indicates expression and a value of 0 means no expression of that opsin in that ommatidium.
originalImage - same organization as clusteredImage, shows the original confocal image.
Access information
Other publicly accessible locations of the data:
- n/a
Data was derived from the following sources:
- n/a
This dataset includes a MATLAB file that includes all of the original eyeshine images that were taken along with the analyzed counts. A second MATLAB file includes immunostaining data for all animals included in the study. The original .czi files for each tissue section is also included. See the README.txt for additional details.
- Buerkle, Nathan P.; VanKuren, Nicholas W.; Westerman, Erica L. et al. (2022). Sex-limited diversification of the eye in Heliconius butterflies [Preprint]. Cold Spring Harbor Laboratory. https://doi.org/10.1101/2022.04.25.489414
- Buerkle, Nathan P.; VanKuren, Nicholas W.; Westerman, Erica L. et al. (2025). Sex-limited diversification of the eye in Heliconius cydno butterflies. Journal of Comparative Physiology A. https://doi.org/10.1007/s00359-025-01768-z