Science Stories: From Bean Plant ‘Air Support’ to Black Chernobyl Frogs

From bean plants summoning predatory wasps to defend themselves against caterpillars to frogs adapting to radiation in the shadow of Chernobyl, our resident science guy Joe Johnson brings us the science stories that caught his eye this week.

One study, published in the Proceedings of the National Academy of Sciences, examined how common garden beans respond when caterpillars begin feeding on them.

“Plants in general have developed a number of physical and chemical defense strategies,” Johnson said. “It’s like a biological arms race. It’s really, really fascinating stuff.”

Researchers focused on a chemical receptor in bean plants that reacts to a substance called inceptin, found in caterpillar saliva. When activated, the receptor triggers the release of airborne chemicals that attract predatory wasps, which in turn attack the caterpillars.

To test the process, scientists grew both normal bean plants and plants with a natural mutation that disabled the receptor. The plants lacking the receptor attracted significantly fewer wasps.

“The plant is under attack, and it calls in air support,” host Jason Dole said during the discussion.

Johnson noted that while scientists debate whether plants can be said to “intend” such actions, the result is clear.

“We don’t know if it’s intending to do that,” Johnson said. “But it is the result.”

The findings raise intriguing possibilities for agriculture. Johnson wondered whether similar traits could someday be introduced into other crops to improve natural pest resistance.

Powerful Volcanic Eruption Cleaned Up Part of Its Own Methane

A study published in Nature Communications examined the massive 2022 eruption of the Hunga Tonga-Hunga Ha’apai volcano in the South Pacific. The eruption blasted ash, seawater and gases high into the atmosphere, creating a plume visible from space.

“This was a monster of a volcanic eruption,” Johnson said. “The explosion video from space is just amazing.”

Scientists studying the plume detected unexpected amounts of formaldehyde, a compound not typically associated with volcanic emissions. Researchers believe the formaldehyde may have formed when methane reacted with chlorine and bromine from seawater salts in the presence of sunlight.

The discovery could provide new insights into how methane — a potent greenhouse gas — breaks down in the atmosphere.

“At present, this mechanism for the production of formaldehyde in the air after the eruption is only a theory,” Johnson said. “But I think it’s a really plausible one.”

Researchers observed roughly 900 tons of methane being converted daily within the volcanic plume, according to Johnson.

It’s Not Easy Being Green

Research published in Evolutionary Applications examined eastern tree frogs living within the exclusion zone surrounding the 1986 Chernobyl nuclear disaster. Scientists found that frogs living closest to the reactor were dramatically darker than frogs outside the contaminated area.

“The closer the frogs were captured to the reactor, and so the higher dose of ionizing radiation that they received, the darker they were,” Johnson said.

Researchers believe the darker coloration is linked to increased levels of melanin, the pigment that helps protect living tissue from radiation damage.

“I think this is an example of evolution in action,” Johnson said.

Within populations, some frogs naturally possessed darker skin. Those individuals likely enjoyed greater protection from radiation exposure and were more likely to survive and reproduce, passing along those traits to future generations.

“It’s helping them,” Johnson said. “The radiation here is being an evolutionally driving factor and causing a darkening of the skin to literally protect the frogs so that they can reproduce.”

Image: Extremes of the colour gradient of the Eastern tree frog (Hyla orientalis). On the left, a specimen captured in Chernobyl inside the high contamination zone; on the right, a specimen captured outside the Exclusion Zone. (Germán Orizaola/Pablo Burraco, CC BY)