Butterflies can pass acquired scent preferences on to their offspring

A male bush brown butterfly, on the left, is seen courting a female. Photo by Emilie Dion/NUS
A male bush brown butterfly, on the left, is seen courting a female. Photo by Emilie Dion/NUS

Feb. 3 (UPI) -- When exposed to new pheromones, butterflies can acquire new scent preferences. And as demonstrated by a new study, these preferences can be passed on to their offspring.

The research lends support to the theory of inheritance of acquired traits. Previous studies have shown rats and worms can pass on genetic adaptation triggered by environmental stimuli to their offspring.


For the new study, scientists found Bicyclus anynana caterpillars and adult butterflies alter their scent preferences if they are exposed to new pheromones during development or early life stages.

Pheromones are chemicals emitted by organisms that influence other organisms. They can be both emitted and received. Insects often use pheromones to track down food or to communicate. Pheromones can be deployed to ward off competitors or attract mates, for example.

In the lab, scientists exposed bush brown butterflies, both caterpillars and young adults, to corn leaves coated with the scent of bananas or mangoes. Within a few days, the insects came to prefer corn leaves -- their natural food -- that smelled like the exotic fruits.

In a followup experiment, researchers exposed young females to a new sex pheromone concoction. The females came to prefer males with the new smell.


"These results are significant because they show that insects are not only driven by their instincts, but can also learn from their previous experience and adjust their future behavior accordingly," study leader Emilie Dion, research fellow at the National University of Singapore, said in a news release. "The consequences of their learning abilities on their survival and reproduction can be very important."

Researchers also observed the behavior of offspring of the males and females that adopted new pheromone preferences. Scientists found the next generation of butterflies also showed the same preference for the unusual pheromones.

The results of the study were published this week in the journal Nature Communications.

Scientists suspect the ability to permanently adopt new dietary and sexual preferences could allow insects to diversify more efficiently across new habitats.

"We are now investigating whether this behavioral transmission is maintained for more than one generation, and also probing the underlying molecular mechanisms in our model species, as these remain some of the most exciting unanswered questions in the field of evolutionary biology," said Antónia Monteiro, associate professor of biology at the National University of Singapore.

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