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john hawks weblog

paleoanthropology, genetics and evolution

Photo Credit: Bamboo lemur in the Reserve de Nahampoana, Madagascar. Gerhard Mauracher.

Why do bamboo lemurs have such a diversity of gut microbes?

North Carolina State University has put out a news article about some recent work by Erin McKenney, who is studying the gut microbiome of lemurs: “Can You Guess Which Species Has the Most Gut Microbes?”.

The article has some statistics I’d never seen before about microbial community diversity in these lemurs:

[B]ecause McKenney studies lemurs, she hadn’t really looked at the gut diversity data for unrelated species. So when she shared the bamboo lemur’s diversity numbers with her mentor, NC State applied ecology professor Rob Dunn, she was surprised to learn that bamboo lemurs are superlative: They are home to more types of gut microbes than any other animal in the world (that we know of).
Specifically, McKenney has identified an average of 13,816 different “operational taxonomic units” (OTUs) – or types of microbes – in captive bamboo lemurs.

That’s more than any other animal yet examined, and roughly 14 times more diversity than in humans—even human hunter-gatherers like the Hadza, whose microbiomes are more diverse than agricultural populations.

Bamboo lemur
Golden bamboo lemur. Photo by Brian Gratwicke via Flickr. CC-BY 2.0

Bamboo lemurs have an interesting diet, which includes an ability to tolerate a level of cyanide that would be extremely harmful for most other mammals, so that dietary ecology might be related to their microbial diversity. That’s a “just-so” explanation, and who knows what diet has to do with it?

I just think this is a really interesting question. What difference does it make to have a diverse microbiome? Why would some species vary so much from each other, even within an order (like Primates)? Is this just a series of historical accidents leading to great diversity in some creatures? Or is their evolutionary history shaped by creating microbial niches inside themselves?