LOS BAÑOS, Laguna—The fictional Gotham City, known in comic books as Batman’s home, could be sitting right atop majestic Mt. Makiling—home to around 30 different bat species.
But what interest scientists more, thus becoming a subject of their recent study, are these winged creatures’ almost permanent ectoparasites, or parasites living outside the host’s body.
In a survey in 2011, scientists from the Museum of Natural History-University of the Philippines Los Baños (MNH-UPLB) discovered 10 species of the “bat vampires,” all belonging to the family Nycteribiidae of the order Diptera.
“Bat vampires” are wingless insects, about two to four millimeters long, with claws and legs that look very similar to spiders under a microscope.
The “bat vampires”—also called “bat flies” (fly is a general term used for insects)—live only on a bat’s blood.
“They suck the bat’s blood using their proboscis,” MNH research associate James Alvarez said in a phone interview on Tuesday.
The bat vampire’s proboscis, like that of the mosquitoes, is near the mouth area. “It is hard enough to ‘pierce’ the host’s skin and is also used ‘like a straw’ to suck the blood,” Alvarez said.
The survey, which has a list of Philippine nycteribiids, was published by Alvarez and MNH curators Ireneo Lit Jr. and Phillip Alviola on Jan. 1 in the Brazil-based Checklist (The Journal of Biodiversity Data).
“Checklist provides the latest available data on nycteribiids ‘although (bat vampires) have been existent since 20 million years ago,’” Alvarez said.
The case of “bats falling victims to vampires” is what Alvarez describes as a “unique” parasitic relationship.
According to Alvarez, some of the bat vampire species on Makiling are found to be “host-specific,” meaning they feed only on a specific bat species. Others are “nonspecific” or they suck blood from two or more species of bats.
MNH found bat vampires in four bat species during their survey.
More studies needed
Alvarez, 24, who studied the vampire parasites as his biology undergraduate thesis, said the insect parasites had adapted to become a bat’s almost permanent “partner.”
“They would not fall off even when the bat flies or grooms (by licking or scratching) itself,” Alvarez said.
“The female (bat vampires) leave their hosts only when they lay their larvae on the bat’s roost but the rest of the time they live on the bat’s body,” he added.
Although the recent publication on the discovery of the bat vampire was a major contribution to science, Alvarez said further studies were needed to learn more about the ectoparasite’s nature and their effects on the bats.
“We have to look at it more seriously because they feed on hosts (bats), which are known to carry diverse and virulent disease-causing pathogens,” Alvarez said.
Risk to humans
For instance, the Ebola virus disease, a fatal human illness that first occurred in Central Africa, is being associated with the bats, he said.
In a statement, Alviola said bats were major reservoirs of so-called “zoonotic” viruses worldwide, posing a potential health risk when a human is bitten.
Although the incidence of bat bites or human contact with bats was “rare,” Alvarez said the “little vampires” they carried still had the potential to transmit viruses from one bat species to another.
Something humans should watch—if the bat species and their little vampires are indeed stuck “in a relationship” of a different kind.