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Phellopsis obcordata - Eastern Ironclad Beetle

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One of the most productive location for finding new beetles this year has been a bracket mushroom covered hemlock tree about a half mile hike from my house. I'm blown away by the diverse ecosystem of creatures assembled around fungal colonies.

One of the biggest thrills has been discovering Eastern Ironclad Beetles there after dark (Phellopsis obcordata) https://bugguide.net/node/view/46042 . These things are bonkers little tough guys that look like smaller, browner, rougher textured versions of the Nosoderma (Diabolical Ironclad Beetles) out west. 

I've collected a small group of them and am hoping someone else might have tried keeping and breeding them. I have them in a high ventilation enclosure featuring a large bracket mushroom resting on a thin layer of crushed wood and leaves. 

I'm especially concerned about getting moisture levels right. I lost a group of Bolitotherus because they dried out, but keeping the Phellopsis too damp is making the bracket moldy.

I'm also wondering if anyone is aware if there are supplemental foods I should offer them? 

Their behaviors are interesting so far, they spend the daytime among the crushed wood and leaves, and then move to the bracket each night to chew on it. Such interesting little beasts



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I don’t know much about care, but keeping some bark behind the fungus might help them? Planning to sell any of these guys any time soon? Also, it might be good to isolate the fungus in a cage for a while, just until the mold takes its toll and dies off

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On 6/18/2019 at 9:00 PM, AlexW said:

They will likely eat at least some normal darkling foods

OK I will try this! I presume you mean dog kibble/carrot/fish pellets/apple ? Let me know if you've found other reliably standard darkling foods. Thanks!

On 6/17/2019 at 12:29 PM, Bugboy3092 said:

 Planning to sell any of these guys any time soon?

Part of my motivation in working with local species is to try to bring more diversity of North American inverts to the hobby, so I would love to share these with other keepers if I have any success :-) 

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5 hours ago, davehuth said:

OK I will try this! I presume you mean dog kibble/carrot/fish pellets/apple ? Let me know if you've found other reliably standard darkling foods. Thanks!

Yes, fruits/vegs/vertebratefood.

Petals of non-poisonous plants are highly attractive for tenebs, isopods, and other omnivorous grazers; for drought-tolerant spp. they can be dried and left in the cage for long periods (unsweetened cereals and sometimes lettuce can also be used this way).


Do note that grain moths/beetles like Plodia will breed in dried petal piles of sufficiently large size.


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  • 4 weeks later...

Just a brief update--

For whatever reason, I've stopped finding these in the wild the last couple weeks (though they're very cryptic as you can see in the photo below, which contains 3 individuals...)

I've divided the enclosure into 2 halves. 1. a slightly damp side of leaf litter, bark, decomposing wood, and broken chunks of a variety of fungus. 2. And a more dry side of just a single large bracket mushroom.

I've tried supplemental foods: they aren't interested in carrot or dog kibble, but they give some attention to apple. I'll try grains next.

They'll gnaw on multiple kinds of fungal growth. 

Their behavior is puzzling. They disappear for days at a time in the leaves and wood, and then return to the bracket mushroom to feed in the open. In the past week they've started energetically burrowing into the bracket for the first time, rather than scraping along the outer surface. I haven't observed mating (there are 7 unsexed individuals in my group) or anything resembling egg laying. But it's not easy to track what they're doing when they disappear into the various crevices and crannies of the enclosure.

So, they remain alive, active, and mysterious. 


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  • 1 month later...
  • 4 months later...


After about 8 months, the majority of these Phellopsis (perhaps all?) appear to be healthy.  I began this project with 8 adults collected in May-June 2019.

They continue to feed/burrow on multiple species of shelf fungus. The softer ones have been gnawed to dust.

 I keep them on a vertical humidity gradient — I keep the thin bottom layer of  leaves/wood/moss slightly damp, and let the pile of brackets above become more dry. 

They move around the enclosure a lot, mostly at night. They’re incredibly shy, I’ve basically never directly observed them eating or walking because simply the act of removing the lid causes them to tuck and freeze for extended periods of time. 

I've seen no mating, egg laying, or larvae. Larvae are likely to be in the bracket interiors. I’ve broken open a couple pieces but so far haven’t seen any definitive larval tunnels. Obviously I don't want to rough them up too much, so I'm trying to be patient.

Photos below:

- Adult just hanging out on a dry piece of moss

- Powdery remains of one if the older/softer brackets

- Individual wedged into a crack on a harder bracket

- The approximately 12-inch wide enclosure

- Individual burrowed more deeply, head first, into a bracket






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  • 1 month later...

So things seemed to be lagging the last couple months. It became hard to locate the beetles in the enclosure. The soft brackets were getting funky, the hard brackets were frequently dry and rarely had beetles on them. I cracked open the edges of a couple more pieces and still no sign of larvae inside. It was hard to know how to keep the humidity and I felt maybe something was off. 

so I decided to freshen the whole thing up. I tidied up the enclosure, and moved the moss to one side to keep one half consistently humid. Added a little dry leaf litter. 

most importantly I hiked out to the source tree and brought home a fresh bracket. 

This seemed to be what they were waiting for. The next day all the beetles had found the new bracket and nibbled the surface  

And it looks to me like mating in the upper left of the below pic

It’s been about 10 months with no fatalities. My hopes are still high that I can crack the egg laying code?




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Good luck, fingers crossed you can get offspring now that the new bracket fungus has reinvigorated them! :D

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  • 4 months later...


Too dry? Too moist? Who knows? After a year all original beetles remain alive. Honestly they seem able to adapt and deal with many environmental conditions, but how to induce egg laying remains a challenge. Either I haven’t yet cracked the code, or the brackets contain larvae that I can’t see. 

My local weather turned very hot and very dry. Worried about these beetles, I believe I over-misted them. I noticed this week they have left the new, fresher fungus they were enthusiastic about in February, and returned to the older, cruddier fungus from last year. Inspection revealed a kind of mold  or something growing on the newer fungus, I assume a hazard from too much moisture. 

I hiked out to the source tree, retrieved another fresh fungus bracket, and will allow the extra moisture to dry a bit. 

Photo: the fluffy pale growth that appeared after over-misting. 


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Update: Beetles have taken to the new fresh bracket that I placed in to give an alternative to the bracket from Feb. that was growing mold. I’ve set it into a dry corner of the enclosure and the mold appears to be fading. 

however, on the bottom stump of the moldy fungus, many beetles are burrowing into it. 

sometimes beetles graze the surface. Other times they burrow deep into the bracket. Why? Is the burrowing to create egg chambers?

just recording my observations as time goes by in case they become helpful in the future. 

photos below:

1. beetles grazing the surface edge of a fresh bracket while the moldy bracket off to the side is ignored...

2. ... except for under the stump of the moldy fungus all this burrowing is going on with 3 beetles packed into one of the holes. 



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