How Protein Gets in Trees for Larvae (Theory)

[Acro]

There seem to be many decayed wood/leaf eating species of beetle larvae that need protein in their diets to develop.  Decayed wood and leaves contain little protein, and we know that many larvae will feed on other species of larvae in a tree hole.  Many will even cannibalize their siblings and other larvae of the same species.  However, after hearing/reading many accounts, it seems that many larvae species are found in tree holes with few protein sources (aka they ate all other available larvae).  So where is the protein coming from to help these larvae reach adulthood?

When culturing beetle larvae (of several beetle species) it was found (I believe by Orin McMonigle) that, by adding dry dog food, this would fill the need for protein, thus making it consistently possible to raise many larvae to adulthood.  There has been much experimentation since then, as many keepers have used different types of dog kibble, cat kibble, dry ferret food pellets, and dry fish food pellets, etc.   Currently, their seems to be a trend towards particular koi fish food brands, as they supposedly have a "high protein to low fat ratio".  Yet, people don't go around filling beetle tree holes with pet foods. 

So, that brings us to the theory that I've had for a while.  I came up with my theory, after learning about a tropical pitcher plant (Nepenthes lowii)that started relying on birds and tree shrew droppings for a food source.  At the time, I had a leopard gecko and I was cleaning out it's cage.  It dawned on me that I might be throwing away a precious resource. I mean, what are Leopard Gecko droppings but digested insects and some vitamin and calcium powder.  I tried using some of the gecko droppings in a Nepenthes pitcher plant I had (Tip, don't use the urates, the white chalky part of reptile droppings, as it's concentrated uric acid and it will rot the pitcher). 

This brought me to the thought that reptile/amphibian/mammal/bird droppings may be a natural way that protein gets inside tree holes that contain beetle larvae.  I don't have a leopard gecko any more, so I can't test if larvae will use reptile droppings as a protein source, but if you are keeping reptiles (or other insectivores) this may be a theory to test. 

Wow . . . I didn't mean to make this so long!  Please post your thoughts.

 

[Goliathus]

It's already been established that the larvae of Gymnetina are associated with tree holes, especially in oaks.  The larvae develop on the decomposing wood, leaves and other organic debris that accumulates in them.  I have also heard that because these holes often contain a considerable amount of frass from the nocturnal lasiocampid moth caterpillars that hide in them during the day, the larvae of Gymnetina and certain other Arizona cetoniines (such as Hologymnetis) may possibly feed on this caterpillar frass (either fresh, or as it becomes decomposed).

In Africa, the larvae of many cetoniines, such as Fornasinius, Hegemus and Argyrophegges, are associated with hyrax middens.

 

[Dynastes]

I swore I documented finding owl pellets (feces) in many tree hole habitats locally in beetle breeding articles. Mostly rodent bones in the dirt though I found bones from a deer once in a tree hole down south.