# Something is killing my Bean Beetles



## Reef_Haven (Jan 19, 2011)

I think my bean beetle cultures have been infested by predatory mites. 
My beetles get right to the point of emerging from the bean and then die.

I finally checked them under a microscope and found these little bastards. They are less than 1/10 the size of a bean beetle egg. 

Video quality sucks, but you can get an idea how small and fast they are. You definitely wouldn't spot them with a naked eye.

predatory mites - YouTube

The larvae pupate fine and then as soon as one breaks the surface of the bean, those little suckers can get in and kill any remaining larvae, pupae or beetles.

Guess I am going to destroy all my beetle cultures and start over fresh with mite paper.

Last 2 photos are of beetles that died before they could emerge.


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## jacobi (Dec 15, 2010)

Sorry about your cultures, but thanks for sharing. Very cool.


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## Reef_Haven (Jan 19, 2011)

So, after half a day researching these things, I'm pretty sure I finally ID'd them.

Pyemotes tritici is a species of mite known as the grain itch mite or straw itch mite.

Immediately upon emergence, females of P. tritici are mated and thus almost always disperse as fertilized adults. They can tightly attach to the host body and paralyze it by injecting its venom (toxins). The attachment is explained by their capability for easily piercing the cuticle with their chelicerae in order to suck the host (Tawfik et al., 1981). In addiction, the venom of a single female is enough to paralyze an insect host.

(1) high reproductive potential;
(2) short life-cycle (4-7 days);
(3) no intermediate hosts or food sources required-- all development occurs within the opisthosomal sac of the adult female and all offspring are born live as sexually mature adults;
(4) only females are parasitic and represent about 90-95% of the population;
(5) females mate immediately at birth and begin host-seeking activity;










They are really bad news. P. tritici, may produce severe skin lesions, asthma, or nausea in humans. 
Hope no one else has to deal with these. They are so tiny you'll never see them, but if you find yourself itching or develop a rash after handling bean beetles, these could be the culprit.
I destroyed all my cultures and have been disinfecting everything with bleach.

Some more pix.


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## Shinosuke (Aug 10, 2011)

That is one sexy bug. 



Reef_Haven said:


>


Seriously cool thread, though. Thanks for sharing all that with us. My BB's have barely been producing recently, too. Hopefully it's nothing to do with these little monsters!


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## frogface (Feb 20, 2010)

Interesting! My bean beetles died off too and I found mites in their containers. I wonder if it was the same type. Too late to check now and I don't have anything powerful enough to get detailed pics anyway. 

Thanks to Shinosuke for the new culture which proves to be mite free so far.


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## Enlightened Rogue (Mar 21, 2006)

frogface said:


> Interesting! My bean beetles died off too and I found mites in their containers. I wonder if it was the same type. Too late to check now and I don't have anything powerful enough to get detailed pics anyway.
> 
> Thanks to Shinosuke for the new culture which proves to be mite free so far.


At least it wasn`t one of you`re mutant spiders....this time.

John


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## Ed (Sep 19, 2004)

Enlightened Rogue said:


> At least it wasn`t one of you`re mutant spiders....this time.
> 
> John


Aren't mites still members of the class *Arachnida*?? 

Ed


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## Ed (Sep 19, 2004)

Reef_Haven said:


> So, after half a day researching these things, I'm pretty sure I finally ID'd them.
> 
> Pyemotes tritici is a species of mite known as the grain itch mite or straw itch mite.
> 
> ...


Any reason to think they also can't attack fruit fly cultures? Or isopods? 

Seems like a good reason to keep all of the bug cultures on mite paper. 

Ed


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