Nav: Home

How male dragonflies adapt wing color to temperature

January 23, 2019

CLEVELAND--New research from Case Western Reserve University in how dragonflies may adapt their wing color to temperature differences might explain color variation in other animals, from lions to birds.

Further, the findings could also provide evolutionary biologists clues about whether rising global temperatures might adversely affect some species.

Michael Moore, a graduate biology student, and Ryan Martin, an assistant professor of biology, recently published their findings in the journal Ecology Letters.

"People have long been aware of variation in dragonfly wing color, but what we are showing in this new work is an overlooked environmental factor--how temperature affects coloration," Martin said. "This could turn out to also determine some of the really cool extravagant traits we like to look at, such as coloration in birds."

Their findings follow a two-year study that began with a hunch about how the wing color on male Blue Dasher dragonflies in the western United States was different from their counterparts in Northeast Ohio.

They reviewed vast amounts of dragonfly photographs compiled by citizen scientists on the website iNaturalist.org and then, with the help of graduate student Iulian Gherghel, cross-referenced that information with weather data.

"I went through 600 pictures from the couch to begin this research," said Moore with a laugh. "After that, it was just mapping it with the corresponding environmental and weather data. It turns out that males in the hottest parts of North America have way less colorful wings, and we wanted to know why. "

Dragonfly weightlifting and other experiments

But the research really took off in the summer of 2017 at the Case Western Reserve farm in Hunting Valley, Ohio, as Moore and Hathaway Brown high-school student Cassandra Lis chased down male dragonflies as they fought to defend their respective territories surrounding a pond.

Across a series of experiments, they then marked each male's body with a series of colors for individual identification at the pond, colored some of their wings with a dark marker, and put the different groups through a weightlifting test to measure their strength.

The conclusion: The dragonflies with darker wings absorbed more heat from the sun, much like we do when wearing a dark shirt on a sunny day. That simple act caused the muscles of those cold-blooded dragonflies to warm more quickly, grow stronger and more successfully defend their territory or win females.

Findings may extend to other species

"Further tests, however, showed that, when temperatures were too hot, darker wings caused the dragonflies to overheat and fly poorly," Moore said.

"These findings suggest that this poor flight would then cause those overheated males to lose the territorial battles and their mates, which in turn could be why males in the warmest parts of North America have adapted to produce less colorful wings."

The study's three main conclusions:

1, The dragonfly observations could help scientists explain how similar traits have evolved across the animal kingdom globally.

"We know, for example, that male lions with dark manes tend to overheat more, which translated into how mane size and darkness have evolved across Africa and Asia," Moore said, citing previous scientific research.

"And if it's happening in dragonflies and lions, two species separated by hundreds of millions years of evolution, it's seems possible that it could be a pretty common pattern."

2. Dragonflies with dark coloring--and other animals--could begin to overheat as global temperatures continue to rise if they can't adapt quickly enough, or if they do adapt, might do so by losing their distinctive colors.

3. Because different dragonfly species, like many animal species, mate based on appearance, adaptation to rising global temperatures could lead to more interbreeding because of the confusion over color.
-end-
For more information, contact Mike Scott at mike.scott@case.edu

Case Western Reserve University

Related Color Articles:

Recovering color images from scattered light
Engineers at Duke University have developed a method for extracting a color image from a single exposure of light scattered through a mostly opaque material.
Deciphering how the brain encodes color and shape
There are hundreds of thousands of distinct colors and shapes that a person can distinguish visually, but how does the brain process all of this information?
Fish-inspired material changes color using nanocolumns
Inspired by the flashing colors of the neon tetra fish, researchers have developed a technique for changing the color of a material by manipulating the orientation of nanostructured columns in the material.
Iridescent color from clear droplets
Under the right conditions, ordinary clear water droplets on a transparent surface can produce brilliant colors, without the addition of inks or dyes.
Comparing antioxidants levels in tomatoes of different color
Greater levels of specific antioxidants were associated with particular colorations of tomato fruit.
Turning a porous material's color on and off with acid
Stable, color-changing compound shows potential for electronics, sensors and gas storage.
Color coded -- matching taste with color
Color can impact the taste of food, and our experiences and expectations can affect how we taste food, according to Penn State researchers, who suggest this may have implications for how food and beverage industries should market their products.
Discovery of a simplest mechanism for color detection
Color vision, ocular color detection is achieved with complicated neural mechanisms in the eyes.
Do spiders have a favorite color?
Scientists recently discovered the aptly named peacock jumping spiders have the color vision needed to appreciate the male's gaudy display.
Tiny spiders, big color
There's plenty that's striking about Phoroncidia rubroargentea, a species of spider native to Madagascar, starting with their size -- at just three millimeters, they're barely larger than a few grains of salt.
More Color News and Color Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Accessing Better Health
Essential health care is a right, not a privilege ... or is it? This hour, TED speakers explore how we can give everyone access to a healthier way of life, despite who you are or where you live. Guests include physician Raj Panjabi, former NYC health commissioner Mary Bassett, researcher Michael Hendryx, and neuroscientist Rachel Wurzman.
Now Playing: Science for the People

#544 Prosperity Without Growth
The societies we live in are organised around growth, objects, and driving forward a constantly expanding economy as benchmarks of success and prosperity. But this growing consumption at all costs is at odds with our understanding of what our planet can support. How do we lower the environmental impact of economic activity? How do we redefine success and prosperity separate from GDP, which politicians and governments have focused on for decades? We speak with ecological economist Tim Jackson, Professor of Sustainable Development at the University of Surrey, Director of the Centre for the Understanding of Sustainable Propserity, and author of...
Now Playing: Radiolab

An Announcement from Radiolab