Mealworm confusion, looking for expert
Website: http://www.rabbitindustrycouncil.com
December 18, 2011 7:44 pm
I know you’re terrifically busy in all senses of the word ‘terrific’, but I was hoping you might ask your entomologist backup crew to get in touch.
I’m starting out with mealworms and have some rather odd things going on in the colonies. Major size differences in larval stage just before pupation and in pupae is only the beginning…!
I’m suspecting a mix of species, but which species? Need to know so I can give them each their optimum environments, and I’m totally lost. 
Have pics, can send, can take more…
And any help, as always, is wonderfully appreciated!
Signature: Pamela Alley
Mealworm Pupae
Mealworm pupae size difference
Location: N. California
December 18, 2011 7:55 pm
You ROCK, folks…!
This is a picture of a darkling beetle, matured from one of my mealworm colony pupae–and in the next pictures, you can see there is a huge size difference between two distinct groups. Supplier A’s mealworms are larger at pupation and make large pupae; Supplier B’s mealworms are pupating at a smaller size and result in smaller pupae.
I suspect a mix of species–let me know what photos will be most helpful in ID’ing the darn things?
Thanks so very much for all you do–I swear, I recommend you to about six teachers a year. *evil grin*
Signature: onafixedincome
Mealworm Pupae
Ed. Note: These two emails came minutes apart, and despite the different signatures and email addresses, we suspect they have the same origin.
Darkline Beetle: Mealworm
Dear Pamela and/or Onafixedincome,
Since your two emails came minutes apart, and deal with a similar subject matter, we suspect they are related despite different signatures and different email addresses. Please confirm our suspicions. Additionally, since only onafixedincome sent photos, we are treating this as a single posting and we will respond to both together. Mealworms are a common commercial name for the larvae of Darkling Beetles that are raised as food for a variety of pets including larger tropical fish, turtles, lizards and frogs. The Aquatic Community website has a nice page on Raising Mealworms. The common commercial species is the Yellow Mealworm, Tenebrio molitor, though we suspect other species may also be raised commercially, which might be one explanation for the size discrepancy you have witnessed. Individual species also have considerable variation in size from individual to individual, and this may be partially explained by genetic traits. Perhaps one supplier has individuals that are passing on a gene that is producing smaller larvae and pupae, and this is producing smaller adults. We hope someone with experience will provide a comment to this posting, though sometimes comments take years to be posted. We would recommend that you place a comment to this posting so that you will be notified in the future if there are any comments or answers to your questions.
Whups! My apologies, wasn’t trying to be sneaky…Just brainless as usual, which takes little effort. 
I wasn’t going to send you pics, because they are ‘domestic’ insects, then thought you might find them fun, if not useful, so posted them. The difference in emails was a screwup, and I am sorry.
Any rate, I appreciate your input as always!–can’t imagine how you manage to keep up with all this stuff.
Given the current average of malformation (50%+) thus far on the large pupae, I’m leaning toward the theory that these were treated with with growth hormone to get size–and that the beetles from these may well turn out sterile.
So, I guess I’ll just have to wait and see….Much obliged for the link, it’s always good to learn as much as you can when raising anything, even bugs!
Again, you ROCK!!!
And of course, thank you so very much.
PA
onafixedincome
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