Project Results

About This Project

Male jumping spiders are often extremely colorful, but the function of this color diversity is not well understood because spiders measured to date appear to lack true color vision. We recently discovered that Habronattus jumping spiders have evolved trichromatic color vision via the addition of red sensitivity. Now we want to find out if the appearance of this new color “channel” lead to the diversification of male colors in this animal group.

Ask the Scientists

What is the context of this research?

Jumping spiders are the champions of miniature vision, but so far, studies have not revealed particularly impressive color vision capability. However, we have recently discovered a mechanism that appears to be unique to the particularly colorful genus Habronattus - a red filter that shifts some green-sensitive cells to red-sensitive, like a pair of red sunglasses. This filter results in trichromatic vision, a pre-requisite for “true” color vision. The discovery of color vision in a notoriously colorful group of spiders opens up the exciting possibility of understanding how this evolutionary event may have enabled the explosive radiation of species-specific male color ornamentation. Did color vision pre-date the diversification of male color displays? How has it influenced male color since?

What is the significance of this project?

We have carried out a pilot study comparing retinal filtering from a small number of species across the jumping spider “family tree”. Intriguingly, we have so far only found spectral filters that enable trichromacy in members of the particularly colorful and species-rich Habronattus genus, but not in closely related “drab” groups.

Our visual modeling suggests that trichromatic vision helps these animals discriminate their flamboyant color displays, and may represent an evolutionary key innovation enabling the radiation of diverse male colors in this group. We hope to more robustly test this exciting hypothesis by densely sampling both colorful and drab jumping spider species to more confidently identify when the red retinal filter (and trichromatic vision) might have arisen in this group.

What are the goals of the project?

By using optical, behavioral, and morphological methods, we will use jumping spiders as a model to improve our understanding of why some terrestrial animal groups evolve such fascinating color diversity. Specific goals:

1. To collect specimens of focal species in the colorful genus Habronattus, and from closely related, mostly “drab” genera such as Pellenes, in a way that allows us to understand the history of vision and color in this animals.
2. To determine how the female eyes see male coloration by measuring the spectral sensitivity and morphology of their eyes, and measuring the reflectance spectra of male color ornaments using micro-spectrophotometry.
3. To analyze how males display their ornaments to the female during courtship using high-speed macro videography and digital analyses.