Before rhinoceros beetles reach their famously large size, they go through several stages of development. Successfully raising these beetles as pets means understanding their four life stages and providing them with the specific care they need during each of these stages.
Stage 1: Egg
If you are breeding rhinoceros beetles, you need to provide the proper environment for egg laying. In environments with multiple male beetles, the males may fight using their horns to determine who earns the privilege of mating with the female. After the winner mates, the female will deposit her fertilized eggs underground so you need to provide the proper egg laying environment. In the wild, females usually lay their eggs in areas of decomposing plants or vegetation. To recreate that environment, you need an aquarium that contains at least 8 inches of top or compost soil. If you want your beetles to thrive, you may want a layer of moist substrate below that layer as well. The female can lay up to 50 eggs at one time. The eggs usually take three to four weeks to hatch into larvae. When you realize the eggs have hatched, move the adult beetles into another container.
Stage 2: Larvae
When the eggs hatch, the rhinoceros beetles are in their larvae or grub stage. This stage actually includes three substages known as instar and referred to as L1, L2 and L3. Instar is a period between molts that insects experience as they grow. During all of these substages, the beetle grubs will look similar to maggots or other insect larvae. However, the larvae will grow larger during each molt.
If you want the larvae to thrive, separate the males and females as soon as possible. During the L2 substage, you will be able to see a dent on the underside of male grubs that is not present on the females. If you wait until the third instar, you will notice a size difference between the males and females. At this substage, male larvae can weigh around 3.5 ounces while females weigh less than 2.8 ounces.
During the larval stage, you will need to replace the compost or top soil because the beetles will use the material for food. Place rotting branches or other vegetation in the container with the larvae so they can use these items for food as well. The soil replacement should be done every six months during this stage.
The larval process is slow for rhinoceros beetles. Depending on the specific species of rhinoceros beetle you are raising and the sex of the grub, your beetles may not enter their next life stage for 12 to 18 months.
Stage 3: Pupa
When the larvae start changing from white to yellowish, stop changing the soil. The rhinoceros beetle is entering its third life stage. At this point, the grub will dig itself a chamber in the soil where it will molt one last time. For the next few months, the beetle will remain in that chamber and will not need any additional nutrition or care. The beetle will emerge from its molt but will stay in the chamber until its exoskeleton hardens. At the end of this period, the adult rhinoceros beetle will emerge from its chamber. The length of time required for the beetle to complete this stage varies with sex and species but can last anywhere from a couple of months to another 18 months.
Stage 4: Adult
When the rhinoceros beetles emerge as adults, they can begin breeding immediately. In fact, if male and female larvae were kept together, they may start matching as soon as they emerge from their pupae chambers. In the wild, adults live off tree sap. Pets rhinoceros beetles can be fed watered down syrup, apples, bananas or prepackaged beetle jelly. Rhinoceros beetles usually live only one to two years.