General Information:

To raise a beetle larva (grub), all you need is a plastic container and suitable substrate. Substrate that can be used for rhino beetle larvae are decayed leaves, white-rot wood, or artificially fermented Flake Soil. Details on these substrates can be found in the Beetle Substrate Guide, and my personal recipe for homemade Flake Soil can be found in the Flake Soil Guide.

Growth Stages:

Rhino beetles have 4 distinct developmental stages which are the following:
Egg -> Larva (L1>L2>L3) -> Pupa -> Adult

Within the larval stage, there are also 3 separate stages called L1, L2 and L3 which essentially stands for “Larval Stage one/two/three”. Every time a larva sheds its skin to grow larger, the “L” number increases by one. So L1 larvae are individuals that have hatched from an egg and have not shed yet, L2 larvae are individuals that have shed once since hatching, and L3 larvae are individuals that have shed twice since hatching.

Container Size:

The container size and volume of substrate should be increased every time the larva sheds into the next L number. As a guide, the minimum volume per larva for average sized rhino beetle species such as Trypoxylus dichotomus should be the following:

• L1 – 100 millilitres

• L2 – 200 millilitres

• L3 – 2000 millilitres

Temperature:

The temperature should be controlled according to the needs of the specific species, especially during hot summers or cold winters. Keep the container in a quiet place out of direct sunlight. For example, highland species such as Dynastes neptunus and Dynastes satanas should be raised between 15-20C, and lowland species such as Dynastes hercules and Chalcosoma caucasus should be raised between 20-25C.

Ventilation:

Ensure that there are several ventilation holes in the lid of the container to allow for the aeration so that the larva doesn’t suffocate. Care should also be taken not to add too big of a ventilation hole, or too many holes as this will increase the evaporation rate of water from the substrate which will dry it out quicker.

Humidity / Substrate Moisture:

Rhino beetle larvae will get all the moisture they require from the substrate they eat so there is no need to spray water daily, like when raising other types of insects. This however means that the control of the moisture level of the substrate is of the utmost importance. Substrate that is too dry will lead to larvae not being able to source any water, leading to dehydration. The substrate moisture level should be managed carefully to make sure that it does not dry out too much (to provide the larvae with enough hydration) and that it is not kept too wet.

Substrate that is too dry will cause larvae to shrivel up from the lack of water and die from moisture loss, whilst substrate that is too wet will encourage the growth of bacteria and fungi that can be harmful to the larvae, as well as allowing the proliferation of mite and small flies. The way to check the moisture level of the substrate is to make a ball of substrate in your hand and squeeze hard. If water drips out of the ball when squeezed, the substrate is too wet. If the ball of substrate does not hold its shape and falls apart when released, the substrate is too dry. If the ball of substrate holds its shape and does not drip any water, it is the perfect moisture level.