The Eastern Hercules beetle (Dynastes tityus) is one of the largest species of beetles native to North America, most commonly found in the Southeast region of the United States. These showy rhino beetles are known for their golden-yellow to olive green elytra, mottled spots, and lengthy cephalic and thoracic horns on males. They are a great beginner species, and are quite forgiving in their care for the first-time beetle keeper. This is not meant to be an exhaustive guide on every possible way to care for these animals, but reflects our personal experience.
Basic care:
For adults:
Optimal temperatures: 68-75F/20-24C
Optimal humidity: 60-70%
Adult beetles can be kept in enclosed terrariums at least three times the length of the beetle in any given dimension, or larger. More space is better, but small terrariums are just fine as an individual beetle does not require much space. Males are best kept in separate enclosures, while females can be kept in small groups of two or three with no problems. They should be kept in a loose, soft substrate that is at least two or three inches deep, as they often dig to hide when not exploring or feeding. Coco coir makes for a great substrate as it retains moisture well, will not scuff up and wear down exoskeleton as easily as soil, and resists mold. Sticks, leaves, and bark pieces should be placed on the surface of the substrate to give the beetles something to climb on and aid them in flipping over if they end up on their backs. A secure lid is recommended, as they easily push open loose lids. Metal mesh is fine, but not optimal, as it can wear down their claws faster than normal. The enclosure should be misted regularly to maintain humidity. Conditions outside the optimal ranges can adversely affect lifespan in adults.
Adults are sap and nectar feeders, and will eat soft, sweet, ripe fruits in captivity. Banana, mango, and melon are commonly fed and readily accepted, but citrus fruits should be avoided. Beetle jelly is another alternative to fresh fruit, and can be purchased or easily made at home. Check our resource on making your own!
Adult beetles, after eclosing and hardening, will remain buried and in a low-energy, dormant state for another 2-8 months before becoming active, exploring, and eating. Once active, the typical lifespan is around 4-6 months, but can be as long as an entire year.
For larvae:
Optimal temperatures: 68-75F/20-24C
Optimal humidity: 60-70%
After hatching, larvae develop and gain weight through three separate stages before finally pupating, known as instars; normally referred to as L1, L2, and L3. In optimal conditions, a larva will spend about 4-6 weeks at L1 and L2, and 8-10 months at L3. Taking care of larvae is mostly just a labor of patience, as your goal is to provide them with enough substrate and moisture to grow while disturbing them as little as possible.
The larvae feed on decayed wood and leaves. The best way to keep larvae in captivity is in a substrate of flake soil, an artificially decayed substrate made from sawdust and wood flakes. This can be purchased online, or made at home in 2-4 months. Check our resource on making your own!
Prepared flake soil should hold it’s shape when compressed in your hand without dripping water.
A normal terrarium setup isn’t going to be the best method for keeping larvae. Lidded deli/food containers are perfect. Some ventilation holes are needed, 12-24 pinholes in the lid will suffice. L1 and L2 grubs will do well enough in a 5oz deli cup filled with damp flake soil. Early L3 should be upgraded to a 16-24oz container, and after a few months (we do around when the larva reaches 20g in weight) should be upgraded again to a larger container – we use 64oz containers. Containers wider than they are tall are better, as D. tityus form pupal cells horizontally.
The idea is to keep them in a size of container that will hold enough for the larva to eat in a single month. From there, you can check in and refresh the flake soil each month to sift out frass and replace the portion that has been eaten. Ideally, some of the remaining soil should be retained and mixed in with the fresh flake as it contains beneficial bacteria and will reduce the potential for shock to the larva from any PH differences between the spent and fresh substrate. Occasionally spraying the surface of the can help keep the substrate moist if it dries out some between changes.
Around the 6-7th (or later) month at L3, the larva will begin to look more yellow, and may not be eating as much. This indicates that they are getting ready to pupate. They will form a hollow, oblong chamber as a pupal cell. If you are using a transparent container, you may get lucky and be able to see if they are forming a cell. The larva will lose weight and become wrinkly as it uses fluid stored in its hindgut to line and smooth the chamber. At this point you do not have to replace the substrate and the best course of action is to just leave them completely alone so you do not accidentally collapse their cell. If you cannot see the larva from the outside, dig slowly and carefully if you are doing maintenance, if you start finding an oval area that sounds hollow or is more compacted than the surrounding soil, that is likely a pupal chamber and should be left alone.
For Pupae:
After constructing a cell, the larva will lose all mobility and pupate. This is when the beetle is the most vulnerable and fragile. Any damage, even a minor crack or dent will be fatal, even if it looks like the pupa is still moving, so the best thing to do is not need to touch it.
If during prepupation when the larva has become wrinkly and immobile, or as a pupa, the cell is accidentally disturbed and either collapses or is broken open, you will need to prepare an artificial cell. One method often used in the hobby is to carve a hollow recess into a block of dampened floral foam, approximately the size of the original pupal cell. It should not be much wider than the pupa itself, as the adult will need to be able to reach the sides to flip itself over when it ecloses.
An easier method of preparing an artificial cell that we have started using is dampened 2-inch peat plant pots cut to fit together end to end. After placing the pupa inside, the artificial pot cell can be half buried again to secure it in place. When moving a pupa for any reason, the best way is to gently tilt them to roll into the palm of your hand so you can avoid accidental damage by picking them up with your fingers.
After 4-6 weeks, the color of the pupa will darken and the head, horns, and ends of the legs will be dark brown, indicating the beetle will eclose soon. A fresh adult will expand its wings and elytra and be soft and white, flipping over multiple times during the process as they begin to harden. If they are unable to flip over due to using too large of an artificial cell, the elytra may be deformed, or they may not be able to fold their wings properly. Elytra deformities may adversely affect the adult’s health, but misfolded wings are not usually much of an issue.
After a day, the adult beetle will have darkened to a deep red, and in a couple days they will have completely hardened and become a dark green/yellow color, and their spot pattern will be visible. As noted above, the new adult will remain dormant for 2-8 months before becoming active. Keeping dormant adults at cooler temperatures (50-65F/10-18C) can help ensure they are fertile and increase longevity. Warmer temperatures will cause them to become active faster, but can subsequently shorten their lifespan.
Breeding:
Eastern Hercules beetles are very straightforward and easy to breed, and a single adult female beetle can lay anywhere between 30-90 eggs if a suitable location is provided for her to do so. Pairing them is as easy as putting a male and female beetle together in a small enclosure with bark to hold onto and a bit of substrate for traction. If both are active and ready, they should mate within a couple hours. Once confirmed, the male should be separated out and returned to his own enclosure. The female can then be placed in a specially prepared laybox, given plenty of food, and left to dig and get to work.
Laybox Preparation:
Optimal temperatures: 68-75F/20-24C
Optimal humidity: 60-70%
Choose a large container with a secure lid – plastic totes or bins work well. A 19Qt/18L storage bin or larger is recommended. Add ventilation holes. For the egg laying medium, a substrate of either pure flake soil, or a 50/50 mix of flake soil and organic garden soil (no additives like fertilizer, perlite, or definitely pesticides!) will work. It should be hydrated enough to hold its shape when compressed without crumbling. If using garden soil, it helps to sift out any stones, clay chunks, or mulched wood pieces to create a more uniform soil mix.
First, fill your bin halfway with loose substrate.
Next, press this down with your hands firmly to create a well-compacted layer at least 3inches/8cm deep.
Fill the rest of the bin back up to at least 50% of the way with more loose substrate.
Finally, add bark, sticks, plenty of food, and of course the female beetle to the bin and secure the lid, leaving it in a place where it won’t be disturbed.
Egg Collection:
Once you have a laybox prepared, it’s up to you for how you want to handle any eggs potentially being laid. You can simply leave the bin alone for a few weeks, changing the food as needed, remove the female, and then wait a couple months to dig in and look for larvae. We prefer to collect eggs to catalog and document how many eggs are being laid, and monitor egg development. This is our schedule and method:
Two layboxes are prepared using the same substrate.
Week 1: Female is placed in Box A.
Week 2: Female removed from Box A and placed in Box B. Box A is left alone, giving any laid eggs a week to absorb water, firm up, and become less fragile.
Week 3: Collect eggs from Box A. Return substrate and re-prepare Box A. Female removed from Box B and placed in Box A. Box B is left alone.
Week 4: Collect eggs from Box B. Return substrate and re-prepare Box B. Female removed from Box A and placed in Box B. Box A is left alone.
This pattern of rotating the two layboxes repeats until we are only finding a few eggs each week, and the beetle is returned to her normal enclosure.
During egg collection, the loose top layer is dumped off and sifted through by hand to see if any eggs were deposited near the surface; normally there won’t be any. The compacted layer is where most or all of the eggs will be. The compacted layer serves two purposes. The first is to create a sense of depth for the beetle, as she will try to dig and lay eggs in deep soil where they’ll be more safe. The second is to pre-compress the soil which lowers the amount of work the beetle needs to do form an egg chamber to deposit in. The female will use her ovipositor to hollow out a small hole that won’t collapse on the egg, so the compacted soil ensures it is more stable and require less work to prepare.
Gently dig out a section of the compressed layer, starting from an edge to try and avoid damaging any eggs. It should be able to be removed in mostly solid chunks. Break these chunks apart by hand, they will often split naturally along egg chambers.
Once eggs are found, they can be gently moved with a spoon and placed in a deli cup. Moist flake soil should then be lightly added on top, and a lid (with a few ventilation holes poked in it) put on. Invert the cup so the lid is on the bottom, this creates a dome where humidity and condensation will form and help the egg to continue absorbing moisture and develop. Freshly laid eggs are very sticky and fragile, but leaving the bin alone for a week lets them begin to develop and are less likely to break or go bad after collection.
Eggs will develop over the course of 4-6 weeks, and the curled larvae inside will become visible. Dark spots for mandibles and spiracles are able to be seen within a day of hatching. Fresh L1 larvae will often eat their egg shell while their head capsule hardens to a brown color, and dig down into the flake soil after a day or two. From here, refer to the larval care section above! Congrats!
