[Minkey]

Just read an interesting article about nematophagous mushrooms. Apparently oyster mushroom releases a toxin that paralyzes and shrinks the nematodes before infecting and digesting them.. this toxin is produced in the mycelium and not the fruiting body so as long as there is some inoculation in the substrate then conditions for fruiting or full colonization might not be needed battle nematodes.

Not sure how common of problem predatory nematodes are for frogs/plants in the hobby but it might be an interesting experiment incase someone is planning on battling a nematode infestation vs. stripping a tank and starting over.

(P.s. I’m not a mycologist but am interested to hear/learn from anyone interested in discussing)

 

[kimcmich]

Greetings,

Oyster mushrooms are one of the more aggressive and substrate-generalist mycelia but their target prey are likely detritivorous nematodes which are far, far more common than parasitic nematodes that harm frogs or plants. I'm sure the fungus would eat whatever nematodes it can catch but frog-afflicting nematodes are likely to spend less time in areas where the mycelia are most common (such as decomposing logs) so I don't think oyster inoculation would be too much of a guard against harmful nematodes.

 

[Minkey]

I was imagining inoculation might happen in the form of orchid bark that would then be distributed throughout the substrate. Again I’m sure you’re right that harmful nematodes are far less common. Seems more of a vivarium ghost story than an tangible threat haha

 

[Encyclia]

I would be interested to see what @Ravage has to say about this. He has a lot of experience with this sort of thing and uses words like "inoculated" a lot

Mark

 

[kimcmich]

I was imagining inoculation might happen in the form of orchid bark that would then be distributed throughout the substrate

Of the many posts showing viv fungi on the board, I've never seen people post oyster mushrooms. This does not mean that the mycelia aren't there, of course (they may be present and non-fruiting) - but it would suggest that vivs are not a particularly suitable habitat for oysters species. That is a shame because there are yellow, pink and blue species of oysters from warmer climates that would certainly be very attractive additions to a viv...

 

[Minkey]

Viv conditions are pretty ideal for oyster species, temperature and humidity wise, likely the intense light is too high to induce fruiting. I would imagine wild spores would probably deplete nutrients before the rest of the vivarium has become overgrown enough to provide dappled or indirectly lit areas for fruiting to occur. I suppose you could introduce colonized wood at intervals to induce fruiting but oysters only gestate around a week before sporing and by that time I would imagine the small prices of wood would either be compromised with other opportunistic fungi or insufficient in sugars for further cycles. This forced sporing action could act as a secondary defense if the previously mentioned orchid bark method is insufficient in culling nematodes in that treatment.

 

[kimcmich]

Viv conditions are pretty ideal for oyster species, temperature and humidity wise, likely the intense light is too high to induce fruiting.

Given the intensity of sunlight in open patches along streams and roadsides where I've collected oysters from logs and snags, I don't think the comparatively dim lights of most vivs would prevent fruiting if oysters were otherwise happy in a viv. Even without direct sunlight, an open patch of daytime sky is very bright compared to a strip of LEDs.

I agree that warm/humid vivs would seem to be ideal for many fungal taxa including oysters - but the lack of fruiting evidence suggests that something - being out-competed by an even more aggressive taxon like Trametes (a mushroom that does fruit in my viv), lack of preferred substrate or a combination of both - limits their success in vivs.

I would also suggest that oyster mushrooms are likely not the only/primary predator of nematodes - a clade so plentiful and ubiquitous that it it likely forms the diet of many organisms.

Perhaps oysters have, in fact, been providing nematode control in our vivs all along (even if they don't fruit). They would just be a specific instance of the more general value of bioactive setups that help keep all kinds of organisms (like molds and mildews) in proper balance.

 

[Ravage]

I would be interested to see what @Ravage has to say about this. He has a lot of experience with this sort of thing and uses words like "inoculated" a lot

Mark

What I have to say is: yes, Oyster mushrooms will parasitize nematodes for their nitrogen. I doubt it would be with an intensity that would eliminate them from your vivarium. This predation is a secondary feeding function and their primary feeding will be on the cellulose in your medium, or Orchid blend. Once they get into a cellulitic medium they will devour it, turning ABG (or whatever) into mush. Mush that will no longer maintain form or allow for oxygen penetration. You will get some big, edible mushrooms, but your tank will go south rapidly. I would assume. I get all sorts of wood rotters in my vivariums, since I have a mushroom lab just down the hallway, but they tend to stay in the wood. And only genera Ganoderma and Fomitopsis tend to be hardy enough to make that trip and settle in. (The bright yellow Leucocoprinus that many see in their vivs are mycorrhizals' and come in with nursery plants, and not as drifting spores) Our terrarium mediums are generally too "dirty" for 'shrooms to get a start. But, if you were to put a chunk of spawn into ABG or similar organic "soil" that probably would take off. And then they* would probably take over until they have consumed everything they can. Then an anaerobic succession would probably begin, at which point you'll be re-building your vivarium.
As for whether they would prefer vegetarian nematodes to predatory ones (or the dreaded nemertean), I doubt they'd care. It's an eat or be eaten world out there, and Pleurotus (Oysters) have been on the top for billions of years.

*I say "they" because that is the prefered personal pronoun of most fungi I've met (Good Lord, I've become Egon Spengler)

 

[Ravage]

Viv conditions are pretty ideal for oyster species, temperature and humidity wise, likely the intense light is too high to induce fruiting.

Oysters have a photo reaction when fruiting and like a day/night cycle. I fruit them with a 12/12 light cycle with ~10K color temp. They would like a cooler (65-70 F) atmosphere than most frogs, but they're no too picky. I like to say in lectures that they'd fruit on mayonnaise if they had to.

 

[Minkey]

Wow thank you so much for that. Incredibly interesting and concise. I really appreciate you sharing your knowledge. What I love most about this board is the wide breadth of knowledgeable members