# Mezium affine (spider beetles)



## pannaking22 (Mar 9, 2015)

Has anyone tried using _Mezium affine_ as feeders? I think they're about the same size as bean beetles, but a bit leggier, so they'd come off as larger. Probably wouldn't work as a feeder for smaller frog species, but they might work for some of the larger ones?

I'm basically just trying to figure out various different feeders I can have on hand to give the frogs variety and to have as backup in case something weird happens with the fruit flies. I don't have any frogs yet, the viv supplies are coming this week and then it'll be a month before the frogs come, but I want to make sure everything is as good and ready.


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## Louis (Apr 23, 2014)

"fullthrottlefeeders.com" is selling them as a feeder insect https://www.fullthrottlefeeders.com/
Springtails and isopods might be lower maintenance backup feeders but I have no idea how mezium affine is cultured. 
I culture Atheta coriaria beetles as an additional foodsource for my geckos and they are pretty easy to maintain. I don't know about darts but the geckos seem to prefer them to bean beetles.


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## hypostatic (Apr 25, 2011)

I've thought about spider beetles as a feeder, but the fact that they have such a varied diet including "vegetation" gives me a bit of pause. I don't know if they would be "safe" in a vivarium full of plants.


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## pannaking22 (Mar 9, 2015)

hypostatic said:


> I've thought about spider beetles as a feeder, but the fact that they have such a varied diet including "vegetation" gives me a bit of pause. I don't know if they would be "safe" in a vivarium full of plants.


Hmm, I guess I hadn't seen the vegetation part before. I was probably thinking more along the lines of they're typically cultured in oats or dry cat/dog food, therefore they'll be fine. Might need to re-evaluate those then. I'd guess they would feed on the decomposing vegetation, but that's probably not a good thing to assume or risk.


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## Louis (Apr 23, 2014)

Seems Hypostatic is onto something. 


> These tiny pests are even known to end up in taxidermied animals or will infest plants. Spider beetles can even end up inside terrariums or herbariums, eating their way through herbs, spices and other plants. You might even find spider beetles munching away at your leather shoes if the infestation is bad enough


https://www.jcehrlich.com/blog/5-facts-about-spider-beetles/


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## hygropunk (Aug 27, 2017)

> I culture Atheta coriaria beetles as an additional foodsource for my geckos and they are pretty easy to maintain. I don't know about darts but the geckos seem to prefer them to bean beetles.


I never knew about these, thank you! Apparently they're used as biological control against fungus gnats and thrips. Having an on again/off again thrip problem myself I'm very interested. The only issue is that they also prey on springtails... I wonder how much of a dent they'd put in a viv population? But I guess if you keep a separate springtail culture it doesn't matter.

How do you culture them?


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## Louis (Apr 23, 2014)

hygropunk said:


> I never knew about these, thank you! Apparently they're used as biological control against fungus gnats and thrips. Having an on again/off again thrip problem myself I'm very interested. The only issue is that they also prey on springtails... I wonder how much of a dent they'd put in a viv population? But I guess if you keep a separate springtail culture it doesn't matter.
> 
> How do you culture them?


Basically the same as you would isopods except I keep mine marginally drier and feed them chicken feed pelllets and a little dried dog food. You can feed both the larvae and adults to other animals. They definitely do eat springtails but adding them to my tanks has never caused the populations to disappear, I suspect they mostly eat springtail eggs and my geckos finish off the beetles before they can wipe them out as the adults beetles in particular are very mobile and don't tend to hide during the day like isopods. I also have strong populations of a large temperate springtail that is about the same size as the beetles themselves and they probably feed preferentially on easier to catch prey like tiny worms and nematodes that tend to be universally present in our tanks. 
Originally I hoped they might also eat small slug eggs but can confirm that they don't as their mouth parts just aren't powerful enough and the eggs are too slimy for them to grip. 
I haven't fed them to dart frogs but honestly there is no food my geckos prefer over these and other rove beetles, something about the way they move just triggers a really dramatic feeding response. 
They tend to be very expensive for an initial culture considering that they actually reproduce very quickly and I don't know about their nutritional profile, I just try to give my micro geckos as much of a varied diet as possible.

EDIT: just to add - Development time from egg to adult has been documented to be 11 to 12 days at 86º F (30º C)


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## pannaking22 (Mar 9, 2015)

Not sure how much I trust pest companies since their whole goal is to make money off of this, but it's definitely enough to make me push pause on these guys as a feeder. I'm talking with a couple people that keep them for fun to get more info as well, so hopefully we'll get info from several sources. It seems that dried goods are the focus of the feeding for them, but if they're willing to eat a variety of things like that who's to say they won't easily move to something else?

Maybe they're good, maybe they're not, but at this point I'm not going to risk my viv or frogs over these. 

Neat info about that staphylinid, thanks for that!


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## Louis (Apr 23, 2014)

pannaking22 said:


> It seems that dried goods are the focus of the feeding for them, but if they're willing to eat a variety of things like that who's to say they won't easily move to something else?


Yeah, even some almost exclusively carnivorous ground beetles _will_ eat plants and particularly decaying plant matter if they have no other option but it's rare. I'd imagine being a grain pest the same is possibly true for spider beetles but I wouldn't bet my rarest or slowest growing plants on it either.
Beetles are amazingly adaptable creatures, did you know mealworms can even eat flame retardant polystyrene?


> This new research found that the mealworms were safely able to eat laced polystyrene foam, and that they ended up concentrating and excreting the flame retardant material, isolating it from other materials. Even better, those polystyrene foam-chomping mealworms could be fed to other animals—the researchers used shrimp—without conveying any of the dangerous chemicals.


https://modernfarmer.com/2020/01/mealworms-can-eat-toxic-styrofoam-safely/


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## pannaking22 (Mar 9, 2015)

Louis said:


> Yeah, even some almost exclusively carnivorous ground beetles _will_ eat plants and particularly decaying plant matter if they have no other option but it's rare. I'd imagine being a grain pest the same is possibly true for spider beetles but I wouldn't bet my rarest or slowest growing plants on it either.
> Beetles are amazingly adaptable creatures, did you know mealworms can even eat flame retardant polystyrene?
> 
> https://modernfarmer.com/2020/01/mealworms-can-eat-toxic-styrofoam-safely/


Never bet against beetles, you'll always lose.

I've actually got a critter keeper full of mealworms I've been feeding Styrofoam to. If the pieces are too small to be of much use for shipping or I can't use them for pinning insects I just break them up and let the mealworms do their thing. Beats all of it ending up in the landfill. I've started experimenting with giving them Styrofoam cups I find all over the place here since people really like to litter. The pieces are a lot thinner, but I'm hoping they'll be eaten by the smaller larvae.


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