The Reason These Poisonous Butterflies Don't Mate Is Written in Their DNA
The Reason These Poisonous Butterflies Don’t Mate Is Written in Their DNA
Wing color and mate preference seem to be genetically bound, leading these tropical butterflies to only choose mates that look like them
Heliconius cydno chioneus(Chris Higgins)
By Rachael Lallensack
SMITHSONIAN.COM
FEBRUARY 8, 2019
About a decade ago, evolutionary biologist Richard Merrill would spend several hours a day in “hot, steamy Panama,” sitting in a cage filled with Heliconius butterflies, waiting for them to have sex.
“Sounds glamorous, right?” he laughs.
Merrill was keeping track of whether male hybrid Heliconius butterflies would flirt—in the form of hovering or chasing—with either red-winged Heliconius melpomene rosina butterflies or white-winged Heliconius cydno chioneus butterflies. He documented this butterfly courtship to study the hybrids’ mate preference, which he and his team would later scrutinize at a genetic level.
In nature, hybrid Heliconius butterflies are rare. Heliconius melpomene and Heliconius cydno are both highly poisonous, having evolved to produce their own cyanide, and predators have learned exactly what both of these toxic insects look like. If the two species interbreed, however, their wing pattern becomes a disorienting mash-up of both color patterns, making the hybrid butterflies a stand-out target for predation. As a result, the hybrids’ lives often end before they can breed.
In a paper published yesterday in the journal PLOS Biology, Merrill and his colleagues have confirmed for the first time that the preferential mating behavior in these butterflies is indeed written in their DNA. Specifically, his team found just three parts of the genome that control at least 60 percent of mate choice behavior.
Read more: https://www.smithsonianmag.com/science-nature/reason-butterflies-dont-mate-genetics-written-dna-180971456/#f9GIoiIMJCXWVmdC.99
