Vampire bats' metabolism mirrors that of blood-sucking insects, biologists find

Credit: Dr Kenneth Welch, University of Toronto Scarborough

A pair of biologists at the University of Toronto has found that vampire bats are able to burn amino acids as a fuel source similarly to blood-sucking insects. In their study published in the journal Biology Letters, Giulia Rossi and Kenneth Welch coaxed vampire bats in their lab to run on a treadmill as a way to measure their metabolism.

Prior research has shown that blood-sucking insects such as tsetse flies fuel their bodies by burning amino acids in the blood of their prey. Vertebrates, on the other hand, are not good at burning amino acids and instead get their fuel from carbohydrates. One notable vertebrate exception is the vampire bat.

The primary component of the bats' diet is blood sucked from hapless victims. In this new effort, the researchers wondered how vampire bats are able to exist on such a simple diet. To find out, they captured several specimens and brought them into their lab for study.

Measuring the metabolism of most flying creatures is difficult—sensors such as oxygen intake devices and heartbeat counters are cumbersome, and when affixed to a flying creature, they tend to influence measurement results.

Because of that, the researchers took another approach. They placed a tiny treadmill inside a small box and then coaxed the bats to walk on it. The team landed on the approach after noting that vampire bats frequently use running as a means of tracking prey. 

Credit: Dr Kenneth Welch, University of Toronto Scarborough

To test their metabolism, the researchers used oxygen intake and carbon dioxide expiration sensors—the latter device measures carbon isotopes to calculate how much of a certain compound was used as a fuel source.

The pair studied the metabolism of 24 vampire bats—each was fed a meal of cow's blood containing both amino acids and labeled carbon atoms. The researchers had the bats run up to 30 meters per minute—the sensors showed that they were burning the amino acids in the blood they had just been fed.

The researchers note that the eating behavior of vampire bats has a lot of risk—amino acids cannot be used to store energy; thus, the bats have to eat every day or risk starving to death. 

by Bob Yirka , Phys.org

Source: Vampire bats' metabolism mirrors that of blood-sucking insects, biologists find