Jennifer Zaspel can’t explain why she stuck her thumb in the vial with the moth. It was just some after-dark, out-in-the-woods zing of curiosity.
She had been catching moths in the Russian Far East. On this July night, she had just eased a Calyptra into a plastic collecting vial. Its brownish forewings looked like a dried leaf. Of the 17 or so largely tropical Calyptra species, eight were known vampires. Males tend to dine on fruit. But on occasion they will drive their hardened, fruit-piercing mouthparts into mammals and sip some fresh blood. They feed off animals such as cattle, tapirs and elephants — even humans.
Zaspel, however, thought she was outside the territory where she might find a vampire species. She had caught C. thalictri. This species ranges from Switzerland and France eastward into Japan. And it’s widely known as a strict fruitarian. (Fruitarian means something only eats fruit.)
Before capping the vial containing this moth, “I just for no good reason stuck my thumb in there to see what it would do,” Zaspel recalls. To her great surprise, “It pierced my thumb and started feeding on me.”
So make that eight-plus Calyptra vampires.
Zaspel is an entomologist now at the Milwaukee Public Museum in Wisconsin. And she still is puzzling over the genetics of the moths at the two Russian field sites she visited in 2006. Males there will bite a researcher’s thumb if offered. But genetic testing so far shows the moths are part of a vast, otherwise mild-mannered species.
Which is just as well. As vampires go, these moths are not stealth biters. “I would compare it to a bee sting,” Zaspel says. For the sake of moth science, one of Zaspel’s colleagues voluntarily tried, despite the pain, to see how long a moth would keep feeding if no one brushed it away. The bite lasted 20 minutes!
Such bites definitely will get noticed. For these moths and other real-life vampires, being smacked to a smear is a bigger danger than getting staked through the heart.
Nabbing the occasional red lunch, or managing to survive on nothing but blood, is far more difficult than it looks in the movies. Relatively few animals manage this lifestyle. And all are indeed remarkable. Vampires include some insects and other arthropods, a few mollusks, some fishes and birds on occasion. Oh, and of course, there are three types of bats.
When dining on blood, there are pressures to gorge as much as possible at each meal. Such heroic volumes, however, can be outright toxic. At the same time, a blood meal is not nutritionally well-rounded. Some key nutrients are missing. Surviving this way takes guts as well as other specialized traits.
Modern tools of genetics and molecular biology are revealing what hidden specializations are needed for blood feeding. Science also is helping to make sense of the lifestyles that go to different extremes — even mouth-to-mouth blood donation.