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Mites In Dermestid Colony - Control Options

Discussion in 'Skulls and Skeletons' started by MaddestMike, Jan 5, 2022.

  1. MaddestMike

    MaddestMike New Member

    * I have edited this post for clarity and additional information*

    It’s long so it’s broken up by sections -

    Best practices
    Available Mite control products
    My observations
    My treatment choice and results


    I have a new colony from Kodiak Bones (Ken is an excellent source for beetles!) and today I noticed I have mites. A dead adult had dozens on its underside and I could confirm them with a small USB/Wifi microscope. Gold-ish/yellow in color and appear similar to clusters of eggs or small frass clinging to the beetle to the naked eye.

    I assume I introduced them. I trust Ken’ beetles!

    Best Practices
    I contacted Ken for suggestions and he provided a very informative reply. It’s worth reading. —
    Mites appear as if most or all of the dermestid larvae and adults are covered with dust; these are hundreds of mites inserted at the leg joints and into the soft tissue between the “sections” of the larvae. They will look almost “stripped” without a hand lens.

    “Youtube” has two excellent videos discussing and demonstrating mites on dermestid larvae. These are worth viewing:

    I have occasionally had customers report other types of tiny invaders that occasionally infest beetle enclosures. I have not known of mites to infest the “container” and not the dermestids themselves. If the pests are found on the walls of the container and the dermestids are not themselves infested, it is not likely the traditional Lardoglyphus mites that cause problems for dermestid colonies. I do not claim to know all of the various bugs that might infest a colony, especially if “beetle-hygiene” has been loose. Fortunately, the same procedures generally cleans up these miscellaneous infestations as well.

    Unfortunately, Lardoglyphus mite infestations are usually close to catastrophic by the time they are discovered. While not caused by too-damp conditions, mites are favored by a too-damp conditions for an extended period. This is often an issue of high humidity or too-frequent watering of the colony. Many substrates, including the frass created by the dermestids, have a property of slowly pulling moisture from the air and slowly soaking into the substrate. The conditions causing the excess moisture should be corrected immediately. Reducing watering or placing a dehumidifier in the area may be considered. Humidity remaining consistently below 60% is considered the safe range for reduced mite potential.

    The substrate must be well stirred and dried out immediately, such as a fan blowing over the substrate.

    Concurrent with cleaning up the dermestids, it is critical to quickly remedy the conditions that allowed the mites to develop originally. Often, high humidity combined with inadequate air-flow through the colony allows moisture to accumulate in the frass or substrate. A vent system or a fan on a timer blowing through the container will help prevent stagnant and damp air.

    Also, the substrate/frass should be stirred up and turned-over frequently. Unlike the ant colonies of my youth, dermestids do not build subterranean structures. If the frass is kept light and dry, even the tiny larvae will have no problems quickly digging back to the surface.

    Importantly, like flies and other pests that can infest a dermestid colony, mites must also be introduced into the colony… Mites most frequently gain entry into the same way other pests do, as a contaminant, either of a food source or on material to be cleaned. Freezing of all material prior to adding to the colony will 100% preclude mites derived from these sources.
    In addition to Ken’s great advice this also is a very good post about mites and likely sources of contamination.

    Mite Control Products

    I looked at three treatments for
    Honeybee mite infestations. There maybe other options.

    I have a BS in entomology and experience with pesticide testing and education so I wanted to know what these options are, how they work, and share it.

    If you have used any of these products or others for mite control, please let me know me know and I’ll add it to the list.

    This is an excellent summary for mite control products for bees:

    Important! Using these products for dermestids is an off-label use. Use them at your own risk! I'm not recommending anything.

    Check Mite Plus Strips
    Mann Lake DC810 10-Pack

    (mentioned as used by others)

    Labeled use: varroa mites and small hive beetles (shb)
    Application - Apply to small carboard strip? Appears to release a vapor. Remove after 42-45 days.
    Active Ingredient - Coumaphos 10%
    Mode of Action - Coumaphos is an Organophosphate that is an Acetylcholine esterase
    inhibitor. This is essentially a neurotoxin that is non-slective (all animals use Acetylcholine in their muscles).

    Because it is listed as controlling SHB, I'm concerned about using with dermestids. However, it clearly is “safe” for bees... It may be a dosage situation - large enough for mites and SMBs but small enough for bees.

    Mann Lake DC799 Mite Treatment, 10 Strips, Brown

    Labeled use: varroa mites
    Application - Place strips such that bees walk on it. Remove strips after 56 days.
    Active Ingredient - Amitraz 3.3%
    Mode of Action - α2-adrenergic agonist / targets octopamine receptors I’ll

    This mode of action was a little tricky to understand for me, but it basically causes a stress response in mites that alters their behavior which later leads to death.

    Because its labeled only for varroa mites it seems like a safer option.

    Formic Pro for The Treatment of Varroa Mites
    (2 Dose (4 Pads))

    Labeled use: varroa mites and Tracheal Mites
    Application - Designed to release a vapor into the hive. Strips are applied for 14-20 days.
    Active Ingredient - Formic Acid
    Mode of Action - Targets the respiratory system of mites (irritant) but also seems to target the mitochondria of the cells (The energy factories of cells) in respiratory neurons.

    Because it is vapor based, rather than contact, it seems a much better option since I observed mites on cleaned bones as well. Mites might not reach a contact strip.

    ONE Box of Ten 50g Trays

    Labeled use: varroa mites
    Application - Place gel tray at top of hive. Tray is removed after 10 days and a second one is placed and removed after 2-4 weeks.
    Active Ingredient - Thymol 25% (a derivative of Thyme oil)
    Mode of Action - Targets octopamine receptors (sa) but may have other effects not well understood.

    Interestingly the gel is intended to be 'cleaned up' by the bees and they distribute it throughout the hive. This suggests that spreading gel throughout the colony (placed on cardboard squares for instance) would be beneficial.


    For me, it seems Formic Pro is the best option and I bought some.

    My Observations

    First: I overthink things and worry all the time. OCD combined with anxiety. So excuse the detail, and some heavy speculating. Even if I’m wrong that “my” mites are a problem, I hope my treatment efforts will benefit others. Onward..

    I believe I introduced them via a roadkill possum or squirrel. They were a mess so I skinned them and froze the rest. It’s very likely I transferred the mites to the tank while handling the pelts.

    My mites are NOT Lardoglyphus.
    They are a yellow/gold color and appear to be smaller as well.
    See Attached image of mite on cotton bud

    What I have observed was a dead adult that had many mites on its underside, with them clustered tightly on the thorax. Because they appeared to be actively feeding, as well as their high density, and clustering around legs and head joins to the thorax, I assume they are feeding on living/recently dead adults rather than scavenging on the dead - where I might see them covering all the leg joints or on molt skins for instance. The dead adult was in my feeding tray so death must have occurred within the previous 6-8 hrs. I check my beetles frequently.

    Additionally, I have seen a severe drop off on 2nd and 3rd instar (very tiny) larvae and what appears to be a drop/stagnation in adult numbers. My current colony is dominated by late instars that appear healthy, and eating a lot.

    I have been watering them by misting paper towels in addition to sponges to keep them hydrated lest dehydration hinder egg production, but my humidity is 30-40% RH and the substrate is dry.

    However, I have not observed mites on foraging adults or large larvae. They are in an aquarium and I can observe the beetles from above and below fairly often.
    The mites are obviously very small so I maybe missing them if there are only a few present. Hard to tell if it’s a bit of frass for instance. It has been confounding me however.

    Based on Ken’s suggestion, I sifted about in the media to check for moisture, and to look for dead adults. I only found two dead adults so I’m wrong that the adults are dying…. But my feeding tray has a stack of cardboard at the back and I call Lardoglyphus the ‘baby hotel’. Small instars will camp out there for protection and they don’t have to go far to eat. I pulled it and looked through it at a light (a cool view of the larvae!) and there were no 2nd or 3rds, but a few 4ths. Comfirms that egg laying has halted.

    My current hypothesis is that mite stress is suppressing egg laying. Or the mites might be feeding directly on the eggs. They might have some other effect or…
    Another distinct possibility is that the mites and my population changes could be entirely unrelated - especially since they are not Lardoglyphus mites. But their appearance and subsequent halting of egg laying leads me to think they are related. Maybe, maybe not.


    I’ve been using the Formic Pro for a few days now.
    See attached images of packaging and label.
    I was alarmed that bee mortality should be expected and in large numbers!!
    I placed one pad in the tank and the smell was VERY intense. (It smells like a combination of vinegar and ammonia. )

    Most of the beetles started diving into the substrate quickly and I couldn’t take a full breath from the tank. Seemed WAY too strong. So I pulled it and ended up putting a piece in a ziplock bag so I could control the release rate better.
    See attached image

    12 hrs after adding the Formic Pro I began seeing mites moving up the sides of glass and now find them on the outside glass as well. It seems the Formic Pro, at my current dosage, has a good repellent effect, and isn’t causing any behavioral changes in the beetles. I wipe down the glass sides with alcohol, (thanks for the suggestion Sea Wolf!) to remove the mites and see if or how many reappear.

    Currently the odor
    is strong enough to smell it faintly when near the tank, but isn’t irritating (to me and the beetles). I am slowly increasing the concentration and will update this post on developments.


    Maybe I have a new species of mite problem? That does, however, sound very unlikely on its face value. I know I have mites, and I know egg laying has stopped. The rest is speculation and educated guesses.

    Regardless, my experiment with Formic Pro might provide a safe and effective treatment for mites. I think it “should” be possible to save a colony if Formic Pro can be used quickly. I believe that once it is introduced, mite feeding is likely to end quickly, as they try to escape the vapor. But my mites are different…

    If you got this far in the post, thank you.

    Attached Files:

    Last edited: Jan 13, 2022
  2. PA

    PA Well-Known Member

    I know formaldehyde will kill and sterilize your dermestids from experiments running old dried-up whole turtles initially fixed in Formalin and then stored in alcohol. However, specimens preserved in only alcohol and later dried and fed to a colony did not sterilize the bugs.

    If Ken sent you clean bugs, and you used proper procedures, there should not have been a mite infection. Always freeze material before adding it to bugs after prep, and never let wild bugs enter your colony - they can have mites on them.

  3. Sea Wolf

    Sea Wolf Well-Known Member

    Years ago, I used Checkmite bee strips and the formulation was formic acid and they worked well. They no longer produce strips with that so the Formic Pro sounds like the replacement for them. The mite invasion was my fault. Introduced white pine shavings and dry dog food. Humidity was a little high and they took over the colony. The Checkmite worked as well as constantly wiping down the sides and edges of the enclosure with a rag wet with alcohol. It didn't get down to the beetles and it killed every one of the mites it came in contact with. By the next day, mites from below had climbed up on the sides again and were killed en masse by the alcohol rag.
  4. MaddestMike

    MaddestMike New Member

    Yeah, I assume I introduced them. I feel pretty confident Ken sends clean beetles.

    I think I brought them in by handling carcasses and not freezing them before skinning. (Roadkill Possum) I have a freezer full of little guys but the possum was a bit big to put in before skinning it and carving meat off. Next time I'll be using strict hygiene and isolation techniques. Lesson learned.

    It's great to hear about the formic acid working! I like the alcohol wipe down as they move to escape. Will do that for sure. I'll post updates with some pics.
    I wish I had taken a photo of the dead beetle. My scope can take pics... Might have been helpful for others. If another tragedy strikes, I'll record it.
    Last edited: Jan 7, 2022
  5. Sea Wolf

    Sea Wolf Well-Known Member

    I also had a small spray bottle that had an adjustable spray end. I misted the sides with alcohol before wiping with the rag wet with alcohol. What little bits of liquid ran down the sides to the frass really did no harm as the beetles immediately ran away from it. I would just avoid allowing a lot of it to run down the sides.
  6. MaddestMike

    MaddestMike New Member

    Good tip. On the alcohol spray.

    The Formica pro arrived today and I’ll update shortly.