Yeast

[Dynastes]

Also known as the crazy guy who feeds dog food to his grubs (believe it or not the worldwide beetle community thought it was a crazy idea in the mid 90s) I'm never content to stop experimenting. I tried yeast supplementation over the last year or two and the final results with Dynastes tityus seemed moderate as the timing on emergence was almost perfect, even more congruent than when kept in batches, but there were no monsters or notable benefits. I only recently noticed a major drawback: it turned all the adult beetles gray that were fed yeast from 2nd to early 3rd instar. Also, many of the beetles have a thick black collar on the front of the elytra which is not part of the normal coloration of this stock. The adults should have all been yellow due to their specific ancestry. What's even more interesting is larvae fed yeast in the second year but not the first did not have their color affected and still came out yellow.

 

[Regiarbol]

Huh. So it sounds like yeast is more of a peculiar ordinator than a genuine benefactor.

 

[Phil Kuhns]

Huh! That is very interesting! do you have any pictures to post of the grey beetles?

 

[Dynastes]

There were about a 100 of them. I took a few representative photos I'll throw up eventually.

 

[What]

Isnt yeast a fairly common additive to substrate used for fermenting it? Interesting results though.

Edit: one of many links

 

[Dynastes]

Isnt yeast a fairly common additive to substrate used for fermenting it? Interesting results though.

Edit: one of many links

One problem with simply mixing yeast into substrate as though beetle media were dough is fungus and mites are likely to consume it before the beetles. Fermentation and feeding are not the same thing. The feeding methodology is usually more important than the food itself. In answer to your question: yeast has been added to various invertebrate media including fruit fly media since probably before your grandparents were born.

 

[What]

I guess the point I was making wasnt exactly clear.

What makes your "methodology" so different from those who use yeast in their substrates and have not noticed any color changes such as the ones you have? If it is a common additive to substrates and grubs usually have their substrate changed at one or more points along their life cycle... I would think maybe someone else would have noticed this too?

I do not doubt that your beetles displayed this change, Im just pointing out the possibility that yeast may not be the cause...

 

[Dynastes]

What makes your "methodology" so different from those who use yeast in their substrates and have not noticed any color changes such as the ones you have?

Your question assumes someone used yeast and also knew the original coloration of their culture stock. Neither may be true. Read the link you posted, the guy who wrote in about yeast fermentation wrote "I breed small wild pair right now." He may have killed all his larvae, we don't know. (He planned to use yeast and wood pellets for wood burning stoves as media so chances are they didn't make it past first instar.) I know what mine should look like, including common variations, and have fed them all sorts of things that haven't changed their color.

A tiny amount mixed into substrate and allowed to ferment for a few months probably would not have similar results to direct feeding. If you had read my post is wasn't just the yeast, it was also when they were fed it.

 

[Dynastes]

Here are some thumbnails. I did not adjust the images except to resize and both were taken by the same camera a few minutes apart. The left is normal coloration and the right is the odd coloration. The are the same stock but the normal yellow were started about ten months earlier (stragglers from the last batch).