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Abstract Butterflies have evolved a remarkable 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, but variation across closely related species remains less clear. We compared eye organization inHeliconius cydno, a clade of mimetic, Neotropical butterflies that have been studied in the context of wing coloration and courtship. Using a combination of eyeshine and opsin immunohistochemistry, we identified several sexually dimorphic features of eye organization where male eyes varied with species and female eyes did not. These features included the distribution of a red screening pigment across the eye, co-expression of the two UV opsins within single photoreceptors, and the relative distribution of UV and blue opsin expression in R1/R2 photoreceptors. Together, this suggests a shift inH. cydnomales from an ancestor strongly biased towards the expanded Nymphalid mosaic characterized by blue and long wavelength opsin co-expression, red screening pigment, and green vs. red inter-photoreceptor opponency to one biased towards the basic mosaic consisting of UV-UV, Blue-Blue, and UV-Blue ommatidia. We hypothesize that this sex-limited variability may function to adapt these butterflies to sexually dimorphic behaviors like courtship and oviposition in the context of the natural light environment.
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This content will become publicly available on December 1, 2026
Trichromacy is insufficient for mate detection in a mimetic butterfly
Abstract Color vision is thought to play a key role in the evolution of animal coloration, while achromatic vision is rarely considered as a mechanism for species recognition. Here we test the hypothesis that brightness vision rather than color vision helpsAdelpha fessoniabutterflies identify potential mates while their co-mimetic wing coloration is indiscriminable to avian predators. We examine the trichromatic visual system ofA. fessoniaand characterize its photoreceptors using RNA-seq, eyeshine, epi-microspectrophotometry, and optophysiology. We model the discriminability of its wing color patches in relation to those of its co-mimic,A. basiloides, throughA. fessoniaand avian eyes. Visual modeling suggests that neitherA. fessonianor avian predators can readily distinguish the co-mimics’ coloration using chromatic or achromatic vision under natural conditions. These results suggest that mimetic colors are well-matched to visual systems to maintain mimicry, and that mate avoidance between these two look-alike species relies on other cues.
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- Award ID(s):
- 2242864
- PAR ID:
- 10626651
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Communications Biology
- Volume:
- 8
- Issue:
- 1
- ISSN:
- 2399-3642
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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