A new study that has sequenced internal bacteria makeup of a butterfly has revealed some surprise discoveries about metamorphosis.
According to a press release, scientists sequenced the bacteria of the red postman butterfly to learn more about the insect's three major stages of life. Found commonly in Central and South America, the red postman butterfly is known by its scientific name Heliconius erato.
"What we saw was that the microbial community simplified and reorganized itself during the transition from caterpillar to pupa," study lead author Tobin Hammer, a University of Colorado Boulder doctoral student, said in the release. "Then we saw the diversity double after the adult butterflies had emerged and began going about their business of feeding. That was a little surprising to us."
The study, published Jan. 23 in the journal PLOS One, showed that the red postman's internal bacteria was split in half upon transitioning from caterpillar to chrysalis. Also known as the pupal stage, the internal bacteria then doubled again when it went from the chrysalis into butterfly adulthood.
"Butterflies are ecologically and scientifically important, and their transformation from caterpillar to chrysalis to winged adult is one of the most remarkable phenomena of the natural world," said Hammer. "But almost nothing had previously been known about what kind of internal microbes they have and how they change over the butterfly life cycle."
CU-Boulder associate professor of ecology and environmental biology and study co-author Noah Fierer said butterflies are "microbial habitats" for bacteria. The study aims to help the agriculture industry understand why butterflies and caterpillars can be damaging to crops.
"The main question raised by this research is what these microbes are doing inside caterpillars and butterflies to influence their health and behavior," Fierer said in the release. "Now we know that the dramatic shift that occurs as caterpillars turn into active butterflies is matched by large changes in their microbial communities."
Hammer collected his test subjects with a butterfly net and said he chose the red postman because it feeds on pollen, known to be rich in amino acids. Typically, butterflies feed on nectar and have very short lifespans. The red postman, however, can extract nutrients from the pollen and greatly extend its life.
Said Hammer, "This is a unique trait to this genus and could be mediated by its microbiome."