Washington, Oct 28 : A previously unknown population of vampire moths has been found in Siberia by entomologists, who say that the bloodsuckers may have evolved from a purely fruit-eating species.
Only slight variations in wing patterns distinguish the Russian population from a widely distributed moth species, Calyptra thalictri, in Central and Southern Europe known to feed only on fruit.
According to a report in National Geographic News, when the Russian moths were experimentally offered human hands this summer, the insects drilled their hook-and-barb-lined tongues under the skin and sucked blood.
Entomologist Jennifer Zaspel at the University of Florida in Gainesville said the discovery suggests the moth population could be on an "evolutionary trajectory" away from other C. thalictri populations.
In January, she will compare the Russian population's DNA to that of other populations and other species to confirm her suspicions.
"Based on geography, based on behavior, and based on a phenotypic variation we saw in the wing pattern, we can speculate that this represents something different, something new," Zaspel said.
"But it is really difficult to say without knowing genetic differences between individuals in that population, and among individuals from other populations, how different this group is going to be," she added.
If it turns out that Zaspel has indeed caught a fruit-eating moth evolving blood-feeding behavior, it could provide clues as to how some moths develop a taste for blood.
Some researchers, she noted, hypothesize that blood-feeding in insects and animals evolved from behaviors such as feeding on tears, dung, and pus-filled wounds.
"We see a progression from nectar feeding and licking or lapping at fruit juices to different kinds of piercing behaviors of fruits and then finally culminating in this skin piercing and blood-feeding," she said.
Chris Nice, a biologist who studies butterfly evolution at Texas State University in San Marcos, said that few butterfly and moth species are equipped with the hook-and-barb-lined tongues needed to pierce fruit.
"The fruit-piercing stage in the first place sets the stage, in a morphological sense, for further transitions into, in this case, the blood-feeding," he said.