Posted Sep 01, 2016
The Hercules beetle is an ideal species if you have been breeding chafers or any of the smaller beetles and now want to try something ‘big’. There may be bigger but this must the 'easiest biggest' species to keep and breed. To succeed needs space and patience but less than many other giants. The subspecies I reared, septentrionalis, comes from Central America but needs the same conditions as its relatives.
I bought a batch of 20 large grubs at an insect show in Paris and took them back to the UK to rear.
Back home, the grubs were housed in a plastic box about 18" L x 14" H x 14" W. The general rule of thumb is that one L3 grub needs about 1 quart of soil. In my opinion this is overly generous and did not have the room, so each box had five large grubs.
I filled the box to about 2" from the top with a mix of 1 part organic peat compost to 1 part rotten white wood, mainly oak and beech. I avoided any coniferous/pine tree wood as it would have killed the grubs. When possible, I added handfuls of rotten oak/beech leaves. The wood and the leaves were rotten enough that I could easily crumble them into small pieces between my hands.
The mixture was kept slightly moist but I was careful not to make it wet. The box was checked regularly to make sure that the grubs didn’t need more food. What makes rearing beetles great is that you only need to check every week or so –very low maintenance!
When the grubs were full grown they turned yellow and wandered for a few days on the surface before going underground to make their pupal chambers. These are egg-shaped hollows made near the bottom of the box out of soil the grub hardens to make a protective shell. So far as I could tell, the beetles hatched from the pupa after about six weeks but remained in their pupal chamber for another one to two months while the casing hardened.
Breeding the Hercules beetles was easy enough. I used a 40 quart (45 litre) box and filled the bottom 6" with organic soil that I compressed very hard. Another layer of soil was added, similar to the mixture used for grubs. I patted this down hard but not as much as the bottom layer. The overall depth of the soil was about 16". On top of that I placed an inch or so of dead leaves and a few rotten lumps of wood. I left a gap of roughly 4" between the lid of the box and the dead leaves. These are strong beetles, so it was necessary to secure the lid.
I kept one pair per breeding box. I found that two males would fight. I also didn’t want to risk two females damaging each other’s eggs as they tunneled through the soil. After mating, the female disappeared into the soil and out of sight for days at a time, laying eggs deep in the compressed soil. The eggs took roughly a month to hatch.
The next generation of grubs took between 12 and 18 months to go from egg to pupa at room temperature.
The adults ate bananas, and some lived up to six months. It is hard to say how long the females lived as they spent most of their time underground.
My best adult males were 5 1/2" long. Not all had long horns but those that did were impressive. I found the species hardy and the larger grubs able to survive periods of ‘neglect’ when I travelled overseas for long periods. I would recommend this beetle species.