📌 What is beetle substrate? (Flake soil)

When I was a child living in Korea, I often asked my mother to buy fermented substrate from an online insect store trying to breeding beetles collected from the mountains.

My mother's first reaction was, "Son, I don't know much. But what's the difference between this and the soil in the mountains?"

And when I came to America, I heard the exactly the same question from my friend.

The rhino and flower beetles prefer Humus, and stag beetles live in rotten wood, so let's say that you are half right and half wrong.

To rearing the larvae of stag beetles, rhino beetles, and flower beetles, breeders must need a fermented substrate.

So what is a fermented substrate?

Fermented substrate is hard wood shavings, especially oak woods, which are crushed raw sawdust with microorganisms and organic compounds such as carbohydrates and proteins, which are then broken down by microorganisms to make energy and nutrients.

To put it simply, since wild stag beetle larvae eat rotten wood, so process of breaking down wood pieces(pellet/sawdust whatever) through microorganisms to create a similar environment or to make it easier to digest is called 'fermentation'.

Ok, so the substrate is made through fermentation of wood.
In the wild, stag beetle larvae eat fermented wood.
However, the larvae of rhino and flower beetle larvae eat humus, but they 'also' eat fermented wood.
Maybe that's the why they are big fatty and greedy.

To sum this up in a little more detail, stag beetles only eat woods that have undergone ‘aerobic fermentation’.

Aerobic fermentation means that the substrate is fermented by circulating air for smooth decomposition activities of microorganisms.
(This is why substrate producers mix their substrates periodically.)

Conversely, anaerobic fermentation means blocking air circulation and rotting the substrate.
A moderately rotten substrate can be a good substrate for rhino and flower beetles larvae, but if it is excessively corroded, it can be poisonous to them.
Above all, excessive moisture increases the chances of harmful bacteria growing, black mold and green mold forming.

In my case, aerobic fermentation is the basis,
First fermented substrates are used for stag beetle larvae.
Second and third fermented substrate is used as rhino and flower beelte larvae.
Aerobic fermentation is sometimes attempted for rhino and flower beetle larvae, but it is not common.

Substrate on which the first fermentation has been completed

Substrate on which the third fermentation has been completed