Butterflies stick to their suburbs

New study reveals that birthplace has a lasting influence on butterflies and humans.

In an article published in the journal Acts of the Royal Society B: Biological Sciences, Macquarie University, Associate Professor at ARC Future, Darrell Kemp, reveals that the American butterfly of passion, Heliconius charithonia, selects his partner and his nesting site according to the plant species that has hosted his own egg.

This discovery is the first evidence that the very early life of butterflies determines the behavior of adults – something many researchers previously thought impossible.

"There was a lot of doubt about it," says Professor Kemp. "How can the conditioning that occurs in a developing caterpillar survive the complete neuronal rearrangement that occurs once it cleans itself?"

"However, this research goes a long way towards demonstrating that it does."

H. charithonia Butterflies feed and lay on more than 20 plant species, all of which belong to one genus, Passiflora.

To establish his findings, Dr. Kemp collected 38 wild female moths from a breeding colony in Florida. These insects breed exclusively on a species of passion fruit called Passiflora incarnarta.

The eggs laid by the cohort were then randomly assigned to either P. incarnarta plants, or a related species, P. suberosa.

After the caterpillars developed into butterflies, the adults were released into a large rainforest enclosure. Here, their reproductive behavior was found to have fascinating imprints of their early-life host transplant experience.

Females raised in P. suberosa tended to mate with males who grew up on the same species, then tended to lay eggs as well. This was the case even though P. incarnarta Generation members were on the whole larger and grew faster.

"Both men and women have been influenced by their place of birth, which is really unusual for insects," says Dr. Kemp.

"It is possible that this type of preferential behavior may influence the development of distinct and isolated populations, or even new species."