Truffles, which are also known as hypogeous sequestrate fungi, don’t depend on wind for spore dispersal like most of their closely related cousins. Instead, these hidden, ectomycorrhizal globules of spore filled fungal tissue entice foraging mammals to eat them. If you have ever smelled or tasted truffles, you quickly realize their ecological function. The pungent, umami earthiness demands attention as your sinuses gather and retain the essence of the forest floor. I haven’t eaten truffles in quite some time, but it’s one of those special tastes you never forget. Once eaten by forest dwelling critters, the spores pass unperturbed through the mammalian digestive system and are dispersed far away from where they were consumed. If these droppings land near plants that they can engage in mycorrhizal mutualisms with, it still takes 7-10 years for their mycelial networks to develop. Even then, truffles only begin to develop 4-6 years after these underground networks are formed.

Although their spores can remain viable for nearly a decade, truffles are highly dependent on their mammalian counterpart. With truffles being found all over the world, different mammals have filled that role of disperser. Before reading about the hypogeous sequestrate fungi, I assumed that pigs where the main dispersers of truffle spores in Europe and Asia (the old world) because of their wide use by truffle hunters. They do indeed disperse these fungal spores, but are not the truffles target species. Although pigs are voracious eaters, they are omnivores that use truffles to supplement their diet rather than exclusively feed on them. A mammal that has a specialized diet of these fungi instead of an omnivorous one are the prime dispersers for this group of species. A common syndrome for becoming the main disperser of truffles is beckoning and it considers more than the organisms diet .

In North America, a major fungal specialist that disperses truffle spores is from an unlikely rodent-the Northern flying squirrel (Glaucomys sabrinus). Like other squirrels in its family, they have a keen sense of spatial memory and can remember and locate truffles by creating complex mental maps. One study found that fungal spore germination was actually enhanced when spores passed through the digestive system of Northern flying squirrels. Red spruce seedlings that where treated with feces from G. sabrinus had improved inoculation of ectomycorrhizal truffle fungi, opposed to seedlings inoculated directly with the truffle spores. These flying squirrels are vital in maintaining the heath of these northern forest communities by providing nutrient sequestering fungi to vulnerable seedlings. As I researched mammalian truffle dispersers on a different continent, I found another small mammal helps support its forest ecosystem by dispersing these fungal spores.