Observation 150375: Rhizopogon luteolus Fr.
When: 2013-10-28
Collection location: Braga, Portugal [Click for map]
No herbarium specimen

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Thank you
By: Elsa (pinknailsgirl)
2013-11-03 14:36:14 CET (+0100)

very much for the explanation, Daniel.

Yes,
By: Daniel B. Wheeler (Tuberale)
2013-11-03 13:50:05 CET (+0100)

Those are photos of animal mycophagy, Elsa. When you find these animal digs, it is an indication that some animal has detected a hypogeous (underground) fungus and is consuming it. An animal will not dig unless it finds something it judges mature.

The animal will dig and sometimes store the fungi found on tree branches for dessication. Later, it will put the dried fungi in underground caches for later consumption. Find either one, and you will be happy.

In my area, California Red-backed voles are the major animal mycophagists. They must eat their body weight each day in hypogeous fungi. Chris Maser first found that these voles were not threatened. The story is relevant here.

Chris Maser is a small wildlife biologist working for the Bureau of Land Management (BLM) and Forest Service (FS). In the early 1970’s, he was trying to find remains or animals in a proposed clear-cut in Northern California. He was using live traps, but not having any success. Day after day after day his traps came up empty. He knew from remains of California Red-backed voles found in coyotes and animal scat that the voles were found in the area, but couldn’t seem to find anything. He didn’t know if the animals were rare or merely rarely found.

Finally one day he found a dead vole inside one of his traps. He sent to vole to Dr. James Trappe for identification, and possibly to see what the vole had been eating. Trappe found lots of hypogeous spores inside the vole, and told Masser. The vole had apparently died of fright with a round object in its mouth. The object proved to be an Oregon White truffle. At the time in Oregon truffles were thought to be rare, and in California nearly impossible to find. Maser’s work changed that thinking.

Knowing that voles were now present in the area, he set out noctural traps for them. And suddenly the animals showed up. The animal are only active for a small portion of the day, in the darkest hours of the nght. The longer the nights, the more active the voles become.

Also, the voles were heavy predators of hypogeous fungi. Maser was able to catch a live vole and sent it to Trappe. Trappe received the vole on a Friday. He weight the vole and placed twice it’s weight in fresh truffles in the cage with the vole. Early Saturday he checked the vole again. The animal had died. The truffles were gone. An autopsy of the vole showed it had died of starvation!

An average California Red-backed vole weighs 15-20 grams.

Later studies showed that voles were not endangered in the area. In fact, they were the most common animals in forested lands west of the crest of the Cascade Mountains. I once asked Maser at a symposium how many voles he thought were present per acre of land: 1,000, 3,000, 5,000? He replied at least 3,000 individual animals per acre, more or less. This was astounding. That meant there were more California Red-backed voles on every acre of land than the combined weight of deer, elk, bear, puma, coyotes, wolves, badgers, and other vole predators. One of the smallest animals on the land outweighed the largest animals in the area!

Amd at least 80% of the vole’s diet was hypogeous fungi that were harvested in the dead of night.

The remains of Northern Flying squirrels were found in coyote scat. Flying squirrels and coyotes rarely come into contact during the day. How could the coyotes catch the squirrels?

The coyotes are active at night. The Northern Flying squirrels are also active at night. They are active on the ground only in their pursuit of truffles, which they eat almost exclusively for 6 months of the year. A flying squirrel on the ground is easily predated on by coyotes.

This explanation is getting quite long. Sorry. Stopping now.

here are
By: Elsa (pinknailsgirl)
2013-11-03 03:21:58 CET (+0100)

the photos Daniel. Could you give me your opinion, or anyone else, of course.

There should never be any confusion between Rhizopogon and puffballs.
By: Daniel B. Wheeler (Tuberale)
2013-10-31 01:11:54 CET (+0100)

Rhizopogons should be spongy and loculate. Rhizopogon spores form on the inside and never puff as puffballs do. Puffballs are soft (like marshmallows) and when mature the puff to release spores.

Animal activity is a good indication of hypogeous fungi. They are the first indication I have that mature truffles are in the area, provided the odor is not noticed first. Boars, mice, and voles are omnivorous and would be expected to search-out truffles and Rhizopogons. Rabbits are oppotunistic feeders when they find the sporocarps. Bear, cougar, elk, deer, larger ungulates would be expected mycophagists as well. We know at least 60 species of animals in the Pacific northwest have Rhizopogon and Tuber spores found in their scat.

The California Red-backed vole is known to be a prolific consumer of truffles and truffle-like fungi in my area. Northern Spotted owls predate upon them, and carry ingested truffle spores with them to new locations. A Northern Spotted owl can fly 30 miles a day in his search for food.

Mule deer and elk eat truffles just before going into rut in late October-early November.

Please post more photos. I would like to learn more about truffles in Portugal.

As
By: Elsa (pinknailsgirl)
2013-10-30 20:34:39 CET (+0100)

you can see in the picture in situ, there are pine needles and oak leaves, so the pine must be nearby, I didn’t look very well.

I was thinking… today on my walk near my house, I found some little pits…don’t know if they were digged by humans, but who did it must found something, because they were too many. I could take a picture, do you want to see and give me your opinion?

We have many predators, boars, mices, voles, rabbits, etc. but I don’t know who eats Rhizopogons, it’s the first time I see one… by the way, is there any hypothesis to confuse Rhizopogon with any of puffballs?

Rhizopogons are often associated with Pinaceae,
By: Daniel B. Wheeler (Tuberale)
2013-10-30 19:19:26 CET (+0100)

less commonly with Quercus, never (to my knowledge) with Eucalypts.

Alexander H. Smith collected most of his Rhizopogons in Idaho, with some in Washington and Oregon. While he was credited with being more knowledgeable about Rhizopogons than anyone, he also said he had the largest collection of unidentified Rhizopogons of anyone, too.

R. maculatus, nigrescens, ochraceorubens, roseolus, and vulgaris are also known from the Pacificnorthwest of the US. Pines predominate east of the Cascade Mountains. So that is the likely host of the above. I’m guessing R. corsicus and R. virens are found in Portugal for a reason.

Since Rhizopogons all sequestrate spores on the interior of the sporocarp and rely on animal mycophagy for dispersal, it would be interesting to see what animals dig and eat Rhizopogons in Portugal. Mice? Voles? Squrrels? Pigs? Predators of these?

There are
By: Elsa (pinknailsgirl)
2013-10-30 09:52:21 CET (+0100)

Pines. oaks and eucalypts there. In the place, I think it is a oak but there are pines nearby.

I’ve been looking for information, but didn’t find much. I found a portuguese site that mention these species for Portugal:

Rhizopogon corsicus
Rhizopogon maculatus
Rhizopogon nigrescens
Rhizopogon ochraceorubens
Rhizopogon roseolus
Rhizopogon virens
Rhizopogon vulgaris

Do you have any literature about?

Yes, here I can see.
By: Daniel B. Wheeler (Tuberale)
2013-10-30 03:51:19 CET (+0100)

Rhizopogon luteolus is a fairly common false truffle of Europe.

What did you find this obs. associated with?

Now you can see :)
By: Elsa (pinknailsgirl)
2013-10-30 01:11:19 CET (+0100)
I cannot see locules
By: Daniel B. Wheeler (Tuberale)
2013-10-30 00:29:22 CET (+0100)

in the gleba (center), Elsa. This would have to be something other than Rhizopogon, just for that reason. The presence of venae internae suggests the possibility of Tuber. For it to be Tuber, the exterior (peridium) would need to have venae externae as well (external veins). Rhizopogon luteolus is loculate, the locules related to the pores of Suillus mushrooms.

Created: 2013-10-29 20:49:38 CET (+0100)
Last modified: 2014-03-11 14:36:55 CET (+0100)
Viewed: 306 times, last viewed: 2017-02-06 10:34:17 CET (+0100)
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