Gut microbes may determine lemurs' resilience
Ability to process a different diet helps adapt to change brought on by deforestation. Nick Carne reports.
The unique fauna of Madagascar is providing new information about the complexities of species survival in the face of increasing deforestation.
US researchers have discovered that the resilience or otherwise of lemurs, the cute primates found only on the island off the southeast coast of Africa, may depend on what’s in their guts.
Some harbour microbes that are more specialised than others for the forests where they live, to help them digest their leafy diets.
However, that could make it more difficult for them to adapt to fragmented forests or new locales in the wake of habitat change, says Lydia Greene from Duke University.
You can’t move somewhere new, if you can’t eat the food.
Greene and colleagues compared the gut microbiomes of 12 lemur species representing two branches of the family tree: brown lemurs (Eulemur spp.) and sifaka lemurs (Propithecus spp.)
Both groups eat plant-based diets culled from hundreds of species of trees, but while brown lemurs eat mostly fruit, sifakas are known to eat leaves full of fibre and tannins.
The researchers studied the faeces from 128 lemurs collected by colleagues at seven sites across Madagascar, and after sequencing the DNA of the gut bacteria found some striking differences
The fruit-eating brown lemurs harboured similar collections of microbes regardless of where they lived on the island, but the microbial makeup inside the guts of the leaf-eating sifakas varied from place to place – and in ways that couldn't be attributed to genetic relatedness between lemur species.
Instead, what mattered most was where they lived. Microbes that were common in lemurs living in dry forest were rare or absent in rainforest dwellers, and vice versa.
Greene says the patterns may also explain why many brown lemurs have adapted to zoos and sanctuaries, but only one species of sifaka has been successfully reared in captivity.
They have specialised diets and are completely reliant on having the right microbes to extract nutrients and energy from the food they eat.
"If you look at any one of these fruit-eating species and take away its forest, theoretically it could move next door," says co-author Christine Drea. "The leaf specialists may not be able to."
The findings are reported in the journal Biology Letters.