Wednesday, August 1, 2012

Are you telling me that dog vomit is alive?!




Species name: Fuligo septica

Common name: dog vomit slime mold

Location: Ontario

You might be wondering why I'm including pictures of dog vomit on some wood chips and trying to pass it off as a living organism, and you'd be partially correct. The common name of this organism is the "dog vomit" slime mold because of its obvious disgusting appearance, but that's where the similarities end. Slime molds are neither fungus nor plant nor animal; they're fungus-like organisms, which is why I'm including it in my blog (most mycology texts include a chapter about fungus-like organisms, since many of them cause devastating plant and animal diseases). There are a few phases of the life cycle that are missing since I didn't manage to catch them with my camera. Maybe I'll update the photos if it fruits again.

A slime mold has a few characteristic life stages that distinguish it as part animal, part fungus. First, the "vegetative" or feeding part of the life cycle of a slime mold is an amoebiod stage. Anyone old enough to remember the Barbapops knows what an amoeba is! It's a single-celled animal that obtains nutrition by engulfing particles of what can be considered "food" that it comes across in its environment. These amoeba can also take on any shape since they don't have a cell wall, and so they can fit between small spaces quite easily. Once these amoebiod cells "find" each other, they can gel together into a mass called a plasmodium, and then instead of acting like individual cells they act as one individual organism. Once resources start to deplete in an area, the plasmodium (in the case of this species, that's the stage that's missing; it's bright yellow) turns into a structure called an aethalium. In the case of this species, the aethalium is spongy and a cream colour, as depicted in the top two pictures. This is structure is equivalent to the mushroom that forms in true fungi; the aethalium will eventually produce structures called sporangia that produce spores for the slime mold to blow away in the wind to a new environment with more food. The sporangial stage is depicted in the third photo; in the case of this species the sporangia are a dark purple-brown. The spores germinate into new amoeba and the cycle continues.

In general, slime molds pale in comparison as wood decayers with fungi. Fungi are just so much more efficient that if a slime mold doesn't come along first then the nutrients it can use to sustain life are already gone. For this reason, we call them primary colonizers. So what use does this species have? Well, ecologically not much in the grand scheme of things. Most gardeners who have seen this before find it one of the ugliest living things that could appear in their garden, and immediately ask how to get rid of it. Well, it would be a challenge. It would involve getting rid of all of the woodchips, mulch, grass, plants that are starting to decay, etc. It would involve a massive overhaul of your garden, and would be much more trouble than it's worth. So what should you do instead? How about just enjoy it while it lasts? Slime molds are fleeting organisms that are gorgeous under the microscope, and are absolutely fascinating to watch them go through their life cycle. Beauty is all about perspective! And it's not hurting anything, so might as well let it do what it does.