Fungal Predators: Happy Thought for 3 December 2021

Have a Happy Thought: 

Today I bring you a story of hunter and hunted, already told so perfectly by amazing science communicator and biology professor Dr Jen M that I will just share her words:

Fungi are some of the best track-and-ambush predators of animals on the planet.

Oyster mushrooms (yes, same ones you can buy in the grocery store or grow at home) are vicious predators of nematodes.

For the uninitiated, nematodes are little worms (much smaller than earthworms)

There are two major components of fungi: the mycelium, or the "vegetative part" (think of the majority of your body), and the fruit body aka mushroom or the "reproductive part" (yes, mushrooms are the fungus' naughty bits on display!)

Oyster mushroom mycelium has special cells that produce microdroplets (so small they are essentially impossible to suck up with a pipette to characterize chemically) of nematode neurotoxin.

As a nemotode is wriggling through the substrate (rotting wood, soil) it brushes against droplets

These droplets are NOT adhesive (like in other predatory fungi, because there are several different methods of killing animals that have evolved independently!), but rather act as a homing beacon in the substrate. The nematode swims off, none the wiser.

After about 30 minutes, the nematode will start to experience paralysis, and the fungus will start to pounce.

As the nematode swims through the substrate it is leaving a trail of nematoxin; the fungus hones in on this trail and follows it through the substrate!

Oyster mushrooms are also exceptionally accurate in their tracking ability; because they are tracking their own molecular secretion, they're not "distracted" by other scents. Eventually they'll grow to where the nematode is now completely paralyzed, but still alive.

The fungus continues to grow, engulfing the nematode body (pretty much to hold it still and also protect its new food source from other soil or rotting wood scavengers!).

Once secured, part of the mycelium will start to grow towards the openings on the nematode: mouth and butt.

Keep in mind: all of this is done while the nematode is still alive!

The mycelium penetrating the mouth and anus of the nematode start to digest the "juicy bits" inside the nematode, leaving nothing but the cuticle or outermost shell of the nematode behind.

In nutrient-poor environments, this is how quite a few species of fungi obtain nutrients required for survival: phosphorous, nitrogen, and even a bit of sulfur in the form of amino acid side-groups.

So next time you hear some animal biologist telling you about the marvel that is some dumb cheetah hunting and killing a gazelle or whatever, you can laugh and tell them their animals are dumb and fungi are better. Ha! Take that, animal-predator biologists.

 

Thank you so much to Dr Jen (@awesomebiota on twitter) for bringing us this!

Click here to go directly to this fact: https://twitter.com/AwesomeBiota/status/1444982530218864644?s=20