If you live in a temperate area of the world in the Northern Hemisphere, now is the perfect time to look for mushrooms. Mycophiles like you and me wait all year to find the diverse fall assemblages fruiting from the forest floor. In Western New York, the place I call home, the exceedingly wet September and warmer temperatures has created one of the richest fruiting events I have ever witnessed. The chanterelles are have arrived in abundance, along with the chicken of woods, and I’m sure once the temperature drops a bit, well see a massive fruiting of hen of the woods. It’s always at this time of the year that in my own mind, the perennial fungi, the species that persist throughout the year get pushed on the backburner. I have to remind myself, that there is a horde of other species that are harder to find and are not choice edibles. I thought I would use this week’s edition of Fungi Friday to talk about the different life strategies of fungi. Diatrypella quercina is not a fungus fall foragers yearn to find, but this small flask fungus has a series of adaptations that allow it to persist throughout the year.
Unlike the seasonal vibrant mushrooms that fruit gregariously during this time, the monotonous looking Diatrypella quercina mostly goes unnoticed. How can you blame us though? We only get to find a handful of these seasonal choice edibles during a small window of time during the year. I’ll be the first to admit that I’m guilty when I’m actively searching for a few species instead of meticulously surveying for the entire fungal community. But admitting my fault is the first step towards my mycological recovery.
Seasonal mushrooms that get all the hype take part in a ‘Big Bang’ reproductive event. Environmental cues like temperature and moisture cause the underground network of mycelia to organize itself and erupt out of the soil’s surface. A single one these mushrooms releases billions of spores that in many cases get carried away by air currents. After these masses of spores are released, the fruiting body breaks down, and in some species, the fungus dies altogether. This live fast, die hard type of life history is referred to as an r-selection strategy, and many species outside of the mycological realm have evolved this biological approach. Clams, oysters and most other bivalves are species that also have this r-selection strategy. Like these seasonal mushrooms, these animals release millions upon millions of potential offspring into the environment. The chances of any one of these potential offspring making it to adulthood is slim to none, so r-species have evolved these “Big Bang” reproductive events to ensure their genes get passed to the next generation.
Diatrypella quercina and other flask fungi have another type of life history strategy we refer to as a k-selection strategy. K-species have slower growth, live longer and produce fewer potential offspring than r-species. Now, this isn’t black or white, and like most theories in ecology, there is a gradient involved. Diatrypella quercina isn’t the best example of a k-species since it still produces millions of spores throughout the year, but these flask fungi are definitely shifted towards the k-selected side. A great example of a k-species in the animal kingdom is us humans. We produce just a few offspring throughout our long lives, and we tend to our children for more than a decade. Instead of producing child after child, we provide an insane amount of parental care that equip our children with tools to succeed, and eventually introduce their genes into the gene pool.
The main difference between Diatrypella quercina and these seasonal choice edibles is the adaptations that allow Diatrypella quercina to live during the driest parts of the year. The flask fungi are the kings of water retention. They can easily carry out their life cycle even through the harshest summer months. Their almost-closed fruiting structures known as perithecia readily hold onto water, and in Diatrypella quercina these structures are withheld in tissue called stroma. Not only are drought resistant perithecia, housed in hardy, drought resistant stroma, but the majority of the stroma is sunken into the wood it feeds from. This wood acts as another barrier, so water molecules really do have a difficult time escaping this peculiar little fungus.
Not only are there an incredible array of fungi, but a wide variation of life history strategies these fungi possess. I’m obsessed with the seasonal fungi fruiting as we speak, and honestly, I can’t wait to go on a hike on my day off tomorrow to find them. But when you go on your hikes, don’t make the mistake I commonly make during this time; look and appreciate all fungi. See the forest floor through an ecological lens, and realize the amazing diversity of life history strategies fungi possess. K and r-selected species represent not just two types of species, but a gradient of life history strategies. The flask fungus Diatrypella quercina leans more towards the k-selection side of the gradient, as its adaptations allow it to fruit and produce offspring through the year, even in the driest months.