Sunday, April 10, 2016

My Hairy Fungus Beetles, Mycetophagus sp

Over a month ago I was walking down a trail and was looking under stones, and I found two small beetles. I had never seen anything like them, and wanted to get them identified, so I caught them and continued looking for other bugs.

When I got home I took some pictures of them, and prepared an enclosure for them. I filled it with less than an inch of coconut fiber, put a layer of dead leaves and a piece of rotten wood in as hides, and a piece of cat food in the enclosure.

After flipping through "A Field Guide to the Beetles of North America", I identified them as a Mycetophagus species. I uploaded some pictures to and they agreed with my ID. What species exactly, I'm not sure, the one species I can find that has been recorded from Idaho looks nothing like my ones. Perhaps this represents a new species, who knows?

So after learning that they ate fungus, I tried putting some more cat food in the cage to get mold growing in the enclosure. It did get moldy, but there were no signs of them feeding on it. For about a month I kept them in that enclosure, twice I let the cage dry out due to forgetfulness, and I put a few more pieces of cat food in the enclosure as the old ones were rotting away. Nothing seemed to affect them, they were still alive after all that time, yet it did not seem like they were really eating anything.

A few days ago I glanced over at their enclosure and saw something pale moving around. I took a look in the enclosure and there were a couple dozen larva crawling around, of all different sizes. There was even a pupa in the cage! The substrate had dried out yet again, but it did not really seem to bother the larva at all. I moistened the substrate quickly, and took a look at the cat food in the cage. It had gotten rotten and brown, and most of it had been devoured by the larva. I put more cat food in, and the next day they were eating it. It would seem that these guys do not need fungus in their diet to develop, seeing as they ate fresh cat food as well as the rotten stuff.

Many of the larva have burrowed down and pupated, these guys grow really fast and soon I should have a bunch of adults in the enclosure! Anyway, here are some pictures I took of them today, I don't know if there are any other pictures of the larva of this genus on the internet.



Pre-pupal larva

These guys seem to be really prolific and hardy, and seeing as they eat old cat food they may make a good clean-up crew, I'll have to test it out sometime soon.

Anyway, That's gonna be it for today, I hope you guys enjoyed this post, and I'll see you all next time! :)


  1. Mycetophagus confusus closely resembles your specimens. Bugguide only has them shown in Arizona and New Mexico, but perhaps their range extends farther than we have data for...

    Suppose it is a new species. Give us a species name ;) This could be your place in the history books lol. Either way, exciting discovery. I hope these guys do well!

  2. Hmm you're right, they do really look like M.confusus, I don't see why their range couldn't extend into Idaho. I think I'll be listing these as Mycetophagus cf. confusus!

    It'd be cool if they were a new species though, "Mycetophagus idahoensis", lol! XD They seem to be doing really well, within a week I should have a bunch more adults in the cage, some of the pupa look like they are nearing maturity!