Researchers tracking buckeye butterflies (Junonia coenia) in Arkansas found seasonal changes that extend beyond wing color. Monthly RNA sampling from May to November across three years showed differential expression of genes tied to eye pigmentation, circadian rhythms and temperature stress. Butterflies developing as days shortened emerged darker and basked more, suggesting coordinated shifts in coloration, behavior and likely visual processing. Authors propose seasonal sensory remodeling may be a common survival strategy among animals.
Seasonal Switch: Buckeye Butterflies Change Color, Behavior and Likely Vision
Lead image: Dr. Thomas G. Barnes, U.S. Fish and Wildlife Service / Wikimedia Commons
Researchers have found that seasonal changes in buckeye butterflies (Junonia coenia) go well beyond wing color: the insects also alter behavior and show gene-expression shifts that likely affect how they see the world.
Teams from the University of Arkansas and Cornell University studied populations in Arkansas tallgrass prairies, sampling butterflies from May through November over three consecutive years. Because adult buckeyes live only a few weeks, seasonal differences appear across successive generations: summer-emerging individuals are lighter in color, more active, and disperse farther than those that develop in autumn.
Each month the researchers collected butterfly heads, extracted tissue and sequenced RNA to measure gene expression. The analyses revealed consistent seasonal differences in multiple genes. As days shortened and temperatures dropped in September, newly developed buckeyes had darker wings and spent more time basking in sunlight—traits that coincided with altered expression of genes linked to eye pigmentation, circadian rhythm regulation, and responses to temperature stress.
Although the study stops short of mapping exactly how gene-expression changes produce different visual perception, the molecular results suggest a seasonal reorganization of sensory systems. That could help explain the observed shifts in activity and thermal behavior across generations.
“Not only are common buckeye butterflies interacting with their world differently depending on the time of year, but they probably see the world differently at these times of year, too,” said University of Arkansas biologist and co-author Grace Hirzel.
Why This Matters
Seasonal remodeling of sensory systems—paired with changes in coloration and physiology—may be a widespread strategy that helps animals cope with shifting environmental conditions. Further research will be needed to link specific genetic changes to alterations in vision and to test whether similar seasonal sensory shifts occur in other species.
Study Source: Functional Ecology (study of seasonal gene expression and behavior in Junonia coenia).
