comments 4

bugs and mushrooms

We’ve been experiencing unseasonably cool temperatures here in Southern Ontario. I wonder how much that will affect the timing of the fruiting of morels this season. I wish I had a better understanding of the triggers that cause various mushrooms to appear. Is the primary driver temperature? Or perhaps it has more to do with hours of available daylight? Moisture content is clearly important but how do all the factors fit together? I have some understanding of some of the relationships between certain mushrooms and certain trees, but as far as mushrooms go, I haven’t been at it long enough to really have a good feel for the timing.

In my little brain, I associate the fruiting of morels with the emergence of a mayfly called Ephemerella subvaria, the famous Hendrickson. But that’s merely a casual observation and I don’t know if it really holds true. It would be very interesting to document those relationships over time. I know that some people have studied the relationship between mayfly emergences and the seasonal blooming of various plants. That’s what Bob Scammel’s The Phenological Fly is all about. I don’t know if anyone has studied the relationship between fruiting of fungi and mayfly emergence. Both mayflies and mushrooms have an order if not a precise schedule. I think it would be a lot of fun to spend a few hours every day for a season in the forests and on the streams, observing, photographing, documenting. I think my dogs would enjoy that too!


  1. SME

    It’s *unseasonably cool* in Alberta too. As in snowdrifts in April. 😦

    If you ever figure out mayflies, let me know. I could never understand how some years their populations would just explode, and you could spend hours picking them off tents and window screens!

  2. Salvelinas Fontinalis

    I doubt that the emergence of mayflies and the fruiting of morels have much more than an accidental relationship. Both are very closely tied to environmental temperatures over time (as opposed to say one hot day). In the case of mayflies the larva must grow, pupate and hatch and this process is not a one day event. The warmer the water the faster the process happens which is why the hatch of a particular bug will happen in the warmer downstream waters often a week before it happens in the colder upstream waters. The same sort of thing happens with mushrooms. Mycellium has to expand before fruiting happens and this takes some time and is temperature dependent.

    Farmers measure what they call accumulated heat units which is a total of the amount of time the temperature is above a certain base temperature. A certain corn variety for example might need 5000 heat units to germinate, grow and ripen and it doesnt matter if the heat happens at the start or the end of the cycle, it wont be ready until the total heat unit requirement is met. I suspect that this concept applies to both fungi and to bugs although to my knowledge no one has done any studies to prove or disprove it. The thing is that streams and soil will warm up at different rates depending on winter snow accumulation and sunshine and this will tend to keep the relationship between bugs and mushrooms regularly out of whack. Countering this is the law of averages and I think that by the time July arrives the streams and soil temperatures work their way back into sync. For mushrooms I believe you have to make your comparisons to other things that depend on soil temperatures like dandelion blooms and for mayflies you need to look at other aquatic events.

    • Could be so. Mayflies don’t pupate though….they have an incomplete cycle, just nymphs, duns and spinners. Caddis flies have the fourth state.

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