World's first butterfly bacteria sequenced

Scientists have for the first time sequenced the internal bacterial makeup of the three major life stages of a butterfly species, a project which found that surprising events occur during metamorphosis.
Researchers led by the University of Colorado Boulder used powerful DNA sequencing methods to characterise bacterial communities inhabiting caterpillars, pupae and adults of Heliconius erato, commonly known as the red postman butterfly.
The red postman is an abundant tropical butterfly found in Central and South America.
The results showed the internal bacterial diversity of the red postman was halved when it morphed from the caterpillar to the chrysalis, or pupal stage, then doubled after the pupae turned into active adult butterflies.

The study is important because communities of bacteria inhabiting other insects have been shown to affect host nutrition, digestion, detoxification and defense from predators, parasites and pathogens, said CU-Boulder doctoral student Tobin Hammer.
"What we saw was that the microbial community simplified and reorganised itself during the transition from caterpillar to pupa," he said.

"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," he said.
The butterflies were collected at a field site in Gamboa, Panama, and data analysis was done at CU-Boulder.

"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," Hammer said.
"But almost nothing had previously been known about what kind of internal microbes they have and how they change over the butterfly life cycle," he said.
One reason to study the microbial makeup of caterpillars has to do with the potential damage caterpillars can do to crops, said Hammer.
"People are starting to think about the microbiome of insects as targets for pest control, including insecticides, so we need to know what specific bacteria they contain and how they work," Hammer said.