Moths make reproductive choices based on sounds emitted by plants: New Study

Rya Seltzer, an entomologist at Tel Aviv University in Israel and one of the authors of the study, told The New York Times, “This is new…Plants emit sounds, and insects are really listening to that. They are tuned to that specific sound, and they know the meaning, and they consider it.”

Last year, a study revealed that some plants cry a mournful melody made of ultrasonic clicks or pops when dehydrated or under some other kind of stress. These sounds are undetectable to the human ear but can be heard by other animals, including insects.

How was the new study carried out?

After last year’s discovery, Seltzer and her team began to examine if a moth species called the Egyptian cotton leafworm used clicks produced by stressed plants to decide where to lay their eggs — one of the most important decisions of their lives.

“All of her children are going to develop on that specific choice that she made, and she has to make a fast call and a very good call,” Seltzer told The NYT.

The team first demonstrated that female leafworms choose healthy and thriving plants to lay their eggs as they are more likely to provide enough food for the newborn larvae, instead of on a dehydrated one. Once that was established they analysed the role of clicks in the crucial decision-making done by these moths.

For this, researchers used a hydrated tomato plant on one side of an experimental arena. On the other side, they kept another healthy and hydrated tomato plant but it emitted recorded sounds of distress.

What were the findings of the study?

The researchers found that the moths preferred to lay their eggs on the “silent” plant. This meant that the female moths were not only able to recognise signals that indicate the presence of a plant but also interpret them to decide where to lay their eggs, according to Seltzer.

Jodi Sedlock, a sensory ecologist at Lawrence University in Wisconsin, told The NYT, “They have done an incredibly good study… I think they provide very strong evidence that these moths, this species, is attending to those sounds emitted by plants.” However, Sedlock added that “the reason that they are attending to them is not entirely clear yet.”

Seltzer did admit that more research is required. The next step will be to see how moths might use these acoustic cues in combination with scents and other signals from a plant. (With inputs from The New York Times)