These Butterflies Change Visual Systems with Seasons

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AAnimals are known to change seasonally depending on their environment. For example, an arctic fox that sports a snow-white coat in winter sheds to wear a brown-gray summer coat. These changes are triggered by daylight signals that alter the action of foxes’ pigment-producing genes.

While operating on a different time scale, some butterflies also undergo seasonal changes in their coloration. And a recent study in Functional ecology shows that color changes are just the tip of the iceberg: in at least one butterfly species, they are accompanied by changes in behavior and visual perception.

Researchers from the University of Arkansas and Cornell University studied seasonal changes in Buckeye butterflies (Junonia coenia) of the tallgrass prairies of Arkansas. Since these butterflies only live a few weeks as adults, changes occur over generations. Buckeyes that hatch in summer sport significantly lighter colored wings than butterflies that hatch in fall. Summer individuals were also known to have higher activity levels and disperse further than those hatched in the fall.

Read more: “Are butterflies questioning the meaning of species?

From May to November, over three years, scientists assessed the Buckeye butterfly’s coloration, wing shape, behavior and activity level. From the butterfly heads collected once a month, tissues were collected and sampled for RNA (to determine gene expression). The results showed differential expression of several genes depending on the seasons. As the days became shorter and cooler in September, Buckeyes emerged with darker wings and spent more time basking in the sun. These observable changes were accompanied by changes in the expression of genes related to eye pigmentation, circadian rhythms and heat stress.

While it’s too early to specify how these genetic changes manifest in butterfly perception, it’s fair to say that there’s more going on seasonally than meets the eye. “Not only do common Buckeye butterflies interact with their world differently depending on the time of year, but they likely see the world differently at these times of year as well,” University of Arkansas biologist and co-author Grace Hirzel said in a statement.

Whether or not other animals experience seasonal sensory changes alongside changes in their bodies and physiology remains to be determined. But such sensory changes may explain the observed behavioral changes. “Changes in the development of the sensory system, like those we saw in the Buckeye, could be a common strategy used by many animals to survive changing seasonal conditions,” Hirzel added.

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Main image: Dr. Thomas G. Barnes, US Fish and Wildlife Service / Wikimedia Commons

• Devin Reese

  Published on December 17, 2025

  Devin Reese is the editor-in-chief of Natural history and a science writer based in Alexandria, Virginia.