A Taste for Blood
With his soft voice and friar’s manner, Louis Sorkin hardly seems the type to flout the sensible advice of a nursery rhyme. Yet on a recent afternoon at the American Museum of Natural History, Mr. Sorkin, a renowned entomologist, did precisely, luridly that.
He took a glass jar swarming with thousands of hungry specimens of Cimex lectularius, better known as bedbugs. The small, roachy-looking bloodsuckers have been spreading through the nation’s homes and hotels at such a hyperventilated pace that by next year they are expected to displace cockroaches and termites as America’s leading domestic pest insect. To better understand their habits, Mr. Sorkin has cultivated a personal bedbug colony — very personal.
“You see this mesh here?” he said, pointing to a circlet of wiry material taped over the top of his little jam jar of horrors. The weave is dense enough to keep even newborns from escaping, he explained, but porous enough to allow the bedbugs’ stylets, their piercing mouthparts, to poke through. Mr. Sorkin pushed up his shirt sleeve and pressed the mesh end of the jar against the inside of his right arm. Roused to a frenzy by the twin cues of heat and carbon dioxide that “in evolution equal host,” said Mr. Sorkin, the insects scrambled toward the lid, thrust out their stylets and began to feed. For a good 10 minutes, Mr. Sorkin sat there with the proud placidity of a donor at a blood bank. He did not budge. He held the jar. He let the bedbugs bite.
“I can hardly feel it,” he said matter-of-factly, “and they do need to eat.”
Mr. Sorkin and his bedbugs are featured in the newly published “Dark Banquet,” a jaunty, instructive and charmingly graphic look at nature’s born phlebotomists — creatures from wildly different twigs of the phylogenetic tree that all happen to share a fondness for blood.
The book was written by Bill Schutt, a biologist and bloodsucking aficionado who holds joint positions at the C. W. Post campus of Long Island University and the natural history museum, and that day he, too, was at the museum, to discuss the meal plan variously known as sanguivory and hematophagy, and who does it and when, why and how.
Among his rubied rabble are vampire bats tuned to extract blood from large slumbering mammals and bats that aim instead for the warm breast plates of birds; New World leeches that track their hosts through the water and Old World leeches that relentlessly stalk down blood bearers on land; the notorious vampire finches of the Galápagos that daintily peck open dribbling wounds on the hindquarters of blue-footed boobies; and the candiru, tiny, eel-like catfish that are reputed to have the power to swim up a person’s urethra and suck blood from the bladder and thus are often more feared than their fellow river dwellers, the piranhas.
Dr. Schutt, who is waggish and bearded and projects an air of high-voltage goth, also showed off museum specimens of his preferred bloodsuckers, the vampire bats, which in this case were well beyond any need for private Red Cross donations. Yet even post-mortem, the bats’ fur felt silky, their wings said da Vinci, and their faces and teeth showed the hallmarks of a wholehearted blood feeder.
As it turns out, the three species of bat that subsist entirely on blood — all of them native to Latin America — are much cuter than the average insect- or fruit-eating bat. Because vampire bats rely as much on heat and odor signals to find their food as they do on echolocation, they have a comparatively modest “nose leaf,” the knobby nasal organ that many bats use to direct their sonar signals and that helps account for the bat’s archetypal gargoyle appearance. A vampire bat’s incisors and canines are also much sharper and slimmer than standard bat dentition, the better to slip into the flesh of a large mammal or bird without being detected. Then there is the architecture of capillary action. A vampire bat does not suck the blood of its victims but instead lets physics do the sucking, its cleft lower lip, perfectly spaced lower incisors and doubly grooved tongue jointly forming a kind of tube through which a victim’s blood is pulled up as readily as water crawls up the stem of a plant.
The bat hastens the capillary action along, explained Dr. Schutt, “by moving its tongue back and forth like a piston.” That fast-flicking tongue also bathes the wound site in a salivary blend of anticoagulants to block blood’s natural tendency to clot on exposure. In fact, the anticoagulants in bat spit are so potent that a host animal often continues to bleed long after the vampire bat has feasted its fill and departed.