Although “you are what you eat” usually refers to the notion that maintaining a healthy lifestyle means eating healthily, it can also describe the relationship between an organism’s diet and its gut microbiome, which is located in the gastrointestinal (GI) tract and is comprised of trillions of microorganisms/bacteria. Importantly, gut microbiota composition is highly reflective of an organism’s diet, and its diversity plays an integral role in an organism’s health.

In Biology class, you have probably learned about the evolution and speciation of Darwin’s finches from the Galápagos islands based on their beak shapes and diets. One of them, as revealed by a study in 2018, with its astounding diet, perfectly exemplifies the idea that “your gut microbiota is what you eat.”

Source: https://phys.org/news/2021-01-vampire-finches-birds-galpagos-big.html

So, if vampires feed on blood, what do vampire finches feed on?

Let’s start the story with where these finches are endemic: the Wolf and Darwin islands of the Galápagos which are known for their extremely wet and dry seasons. In dry seasons when the primary food sources of finches, such as plants and insects, are scarce, the vampire finches supplement their diet by harvesting blood from blue-footed boobies. Coincidentally, one of the birds I wrote about last week! This is a peculiar strategy that no other finch species (all live on other islands with less extreme climates/ no scarcity of food) have to utilize, and some studies have also speculated that it arose from the once symbiotic relationship between the finch and the booby where the finch would pick insects off of the booby bird.

Source: https://lafeber.com/pet-birds/vampire-finches-ghost-birds/

(This is a vampire finch on the back of a booby bird. I will not be including actual pictures of them consuming blood, but you can search them up if you are curious to see them.)

Now going back to the aforementioned 2018 study and looking at the gut microbiome composition in 12 species of Darwin’s finches, who would’ve thought that the vampire finch would be the odd one out? While the microbiome composition seemed to be conserved across almost all species, vampire finches’ gut microbiota harbored bacteria that were exceptionally rare or entirely absent in other finch species. Since vampire finches consume blood, which is typical in carnivorous diets, their gut microbiome composition included more gut bacteria found commonly in carnivorous birds and reptiles than those found in insectivory or herbivorous finches. Thus, vampire finches’ microbiota reveals the unique type of diet they have and is much more similar to carnivores like vultures and alligators instead of to their sister groups/species. And interestingly, this carnivorous diet has been found to contribute to the diverging gut microbiota in vampire finches, and more studies are under experimentation to investigate the evolution-in-progress of Darwin’s finches due to their different food sources.

A side note: This blog was not planned to be right after Halloween just passed, but I hope you enjoyed reading about this somewhat Halloween blog and this cool bird!

 

Reference:

-https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-018-0555-8