Mealworm pupae turning fushia red and dying

BermyBird

In the Brooder
Sep 24, 2015
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Hi All, What is the mortality rate of your mealworms during the pupal stage? Is it normal for a portion of them to die during pupation and turn black or dark brown? OR, more oddly still, to turn bright fushia red?

Until recently I had not been too concerned, assuming that some some death during this stage is just normal (they are often cannibalized by adult beetles as well). However, ours is a school colony and we recently made agar plates with our Y8's where they inoculated the plates with environmental swabs. The plates were left to incubate on the same shelf as our mealworms. Two days later, about 3/4 of the plates were growing these bright red bacterial colonies that I have never seen before in swab plates. I realized that the plates had been contaminated by grain mites from the mealworm colony being attracted by the agar. I assume that the red bacteria were deposited on the plates from the mites as they grew in little trails along the routes taken by the wandering mites. And that reminded me about those occasional pupae that turn the same colour and die. After looking up 'red bacteria' it seems it could be a rather nasty pathogenic bacteria called Serratia marnescens which is associated with flesh eating infections and is very hard to eliminate!

Has anyone else ever seen bright red dead pupae in their mealworm colonies? I've read that mealworms cannot carry human pathogens but now I have my doubts and have been advised to destroy my entire colony (4 containers worth that I have been nurturing and growing for ages). I'm reluctant but cannot afford to takes chances in a school. I have not been able to find anything similar online that would help me identify why my pupae sometimes turn red and die so perhaps we have a unique problem. If anyone has heard of anything similar please let me know!

Regards, Roz Wingate
 
Hi, welcome to BYC!
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Sorry, never heard of that. But yes, some dead loss during the pupal stage is normal. I would think the brown and black ones may have just dehydrated.

I thought others wouldn't munch the pupa if they had plenty of moisture, though I am sure some don't care even if there is.

You might try posting on this thread, lot's of users....

https://www.backyardchickens.com/t/492636/mealworm-farming/8690

Hope you find answer. Love an educator who has interesting thing for the kids!
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