Goliath beetle is one of the largest insects in the world. They make great pets, but they can be difficult to keep if you have no prior experience. Here’s a guide for those who are interested to keep goliath beetles as pets.
To keep the goliath beetle, place the adult beetle in a ventilated tank filled with 2″ of substrates. Feed the beetle with beetle jelly. Gravid beetles need deeper substrates to lay eggs. Transfer the emerged grubs in containers with substrates and feed them with koi fish food. They turn into adults in 8-15 months.
Goliath beetles are not easy to keep. They behave differently compared to other common beetles. Continue reading to understand more on how to care for your beetles.
- Introduction to Goliath Beetle
- Getting a Goliath Beetle
- Preparing Housing for Adult Beetles
- How to Care for Adult Goliath Beetles
- Temperature and Lighting
- How to Breed Goliath Beetles
- How to Take Care of Goliath Beetle Grubs
- Goliath Beetle Pupation
- Emergence of Adult Goliath Beetle
- Recommended Supplies
- Handling the Beetle
- How to Deal with Mites?
Introduction to Goliath Beetle
Goliath beetle is also known as Goliathus spp. It is a type of flower beetle originated from Africa. The male goliath beetle can grow up to 4 inches (~11 cm) in length.
The male goliath beetles have a small Y-shaped horn on their head used to fight each other for food and ladies. Female goliath beetles lack such a horn.
The back of goliath beetles are painted with colorful markings. Like other beetles, goliath beetles have a pair of hardened wings (elytra) for protection and another pair of wings for flying.
Getting a Goliath Beetle
Depending on where you live, you can buy goliath beetles from your local pet store or online store. Make sure you ask for recommendations from the seller on how to take care of the beetles.
You may want to buy the grubs as they are way cheaper than an adult beetle. You should consider buying at least 3-4 grubs as some of them might not survive to adults.
Always check the age or larval stage of the beetle before buying. Adult beetle can live for 6-12 months. You won’t want to buy a 5 months old adult beetle. If you are getting the beetle from local store, look for sign of injury or lost limbs.
Note that there are several species of goliath beetles, and each species may have different morphs. For instance, there is a white morph or quadrimaculatus form of Goliathus goliathus. It can be up to 10 times more expensive than the normal morph. Due to the high demand by hobbyists though, the white morph population in the wild is declining.
Preparing Housing for Adult Beetles
The dimension of your housing for 1 beetle should be at least 3 times the length of your beetle in length, 2 times in width and 2 times in height. For each additional beetle, increase another 50% to the length and width of the housing.
Bigger housing is better as it gives more space for the beetles to move around. A goliath beetle can be housed easily in a 4 gallon (~16 L) tank. The male goliath beetle is rather aggressive towards other beetles. Hence, do not place a male beetle together with other male or female beetles.
The substrates used for housing are not extremely crucial as they don’t feed on the substrate. Coir, potting soil or peat moss will do the job. You can also use non-soil substrates such as hays.
Remember to put some tree barks or tree branches onto the substrates so that the beetle can hold on to something. When the beetle gets upside-down, it needs to hold on to a solid surface to turn around. Otherwise, it will die trying.
How to Care for Adult Goliath Beetles
The adult goliath beetles naturally feed on tree sap and fruits. You can give them cut fruits such as bananas. Place the fruit onto a sauce plate so that you can clean it easily. Remove any unconsumed fruits every day to prevent growth of molds. Water in the fruit is usually sufficient to support the beetle.
Another option is to feed them with brown sugar syrup. Meier recommends mixing brown sugar and boiled water in a 3:1 ratio and absorbing the mixture using a sponge.
Before using the sponge, it should be washed with water repeatedly to remove any harmful chemicals. You should wash the sponge thoroughly every 5 days between uses to prevent the growth of molds. Always put the syrup sponge onto a plate to keep the substrate clean. I personally think it is rather troublesome to use the sponge method due to the washing requirement.
You should consider feeding your beetles with beetle jelly. It is more convenient to use in terms of cleaning and storage. The jelly doesn’t grow mold as easily unlike the fruits. Some beetle jellies even boast various fitness benefits such as improved longevity, stronger beetles, and larger offspring.
Here is a recipe for beetle jelly that you can try by yourself if you can’t find them in stores.
Temperature and Lighting
You should keep the temperature consistent within 73-80 °F (~23-27 °C). Use heat mat/rock during the winter to maintain the temperature if it is too cold. It is not necessary to provide additional lighting to the beetles. The housing should be placed away from direct sunlight.
How to Breed Goliath Beetles
House both male and female goliath beetles together for mating. Move the gravid female into a container filled with deep substrates for 1-2 months. Feed her with beetle jelly.
Pairing of Male and Female Goliath Beetles
The goliath beetles are ready to mate after they emerged naturally from the pupation cell. To get them mating, put the male and female beetle into the same container. The male goliath beetle will mount itself onto the female to attempt mating. After mating is completed, please separate them.
Goliath beetles can live for 6-12 months in captivity. Try not to mate them when they get too old to ensure a higher success rate in breeding. Note that mating will greatly reduce the longevity of the goliath beetles. If you do not intend to breed them, it is best not to let them mate.
Use a mixture of flake soil and peat in 3:2 ratio as the substrates for the nursery chamber. Add some water to make the substrates wet. You want be able to squeeze the substrate into a shape that holds itself momentarily and there shouldn’t be any dripping water. If it is too wet, add more substrates and mix evenly; if it is too dry, add more water. You should not see condensation on the wall of housing over time, which signifies that the substrates are too wet.
Fill a 10 gallon (38 L) container with substrates up till 12″ (~30 cm) in depth. Compress the substrates at the bottom 2-3” (5-7.5 cm). Cover the chamber with a lid and secure it to prevent the beetle from escaping. Ensure there is adequate ventilation in the chamber.
You can continue to feed the gravid (pregnant) female beetle with beetle jelly or fruits but she may not eat them. One month after mating, the female beetle will start laying 40-60 eggs at the compacted portion of the substrates throughout a couple of weeks. The white colored eggs resemble seeds and are about 0.2″ (0.5 cm) in length.
How to Take Care of Goliath Beetle Grubs
Place the grub in flake soil and give it koi food. Change the substrates every 2 weeks. Move the grubs to a bigger enclosure as it grows. The grub takes 8-15 months to turn adult.
The eggs usually hatch into grubs in around 2-4 weeks time. The grubs of goliath beetles molt 3 times before turning into a pupa and the stages between molts are called the instars.
The first instar grubs can be kept in the same substrates where the eggs are laid. They feed on the rotten woods in the substrates for 1-2 weeks before molting into the 2nd instar. Keep the moisture of substrates slightly lower than the moisture of substrates used for egg laying.
Immediately after the first molt, you should transfer the grub into a 10 oz (~300 mL) container filled with substrate. Do not put more than 1 grub in the same container as they can cannibalize each other. The depth of substrates added should be around 2 times the thickness of the grub.
Make sure your housing is covered tightly while allowing ventilation. Goliath beetle grubs are can be quite aggressive and are able to knock over the housing. Place the housing in the dark.
At this stage, the grub requires high protein food. Take a few pallets of koi fish food and soak it in water for 2-3 minutes to make it soft. Briefly drain the water out from the softened pallet before putting it onto the substrates. The grubs will feed on it.
Alternatively you can use dog food. Koi fish food is preferred due to its higher protein and lower fat content compared to dog food. When you feed your grubs with high fat food, the fat will accumulate on the surface of its mandibles, which may make it difficult for the grubs to feed. Moreover, it also promotes the growth of mites. If you use dog food, you need to soak it longer in water.
The amount of food a goliath beetle grub can consume varies in each day. The grub may eat a lot on certain days but may eat less on some days. They will stop feeding before molting. You can give them enough food that can last for up to 4 days. After that, remove and replace the unconsumed food with fresh food to prevent growth of molt and reduce the chances of mite infestation. Do not leave the grubs without food!
Due to the high protein and fat diet, the substrates get dirty over time. You should replace the substrate every 2 weeks. Otherwise, you will see the grubs wandering above the substrates searching for a cleaner home. Make sure you wash the housing thoroughly with mild soap. You can put the grub under a slow running tap and gently brush the grub with a soft brush to remove all the dirt and fats on its surface.
After another 2 to 4 weeks, the grub will reach the 3rd instar. Move it to a bigger covered and ventilated container (~100 oz/3 L) filled with the same substrate. If you are using a plastic container, secure it with weights or tapes so that it doesn’t topple easily. The grub will continue to feed and grow until it is time to pupate. Continue to clean the grubs and replace the substrates regularly until then.
Because the female grubs tend to grow faster than male grubs, it is not uncommon to have a female beetle dying before a male beetle emerges. This can be prevented by regulating the temperature: keep your male grubs at higher temperature 78-80 °F (~25-27 °C) to accelerate his growth; Meanwhile, female grubs can be kept at 73-75 °F (23-24 °C) to slow down her growth.
But how do you know if the grub is male or female? To sex the goliath beetles grubs, look at the abdominal. You would notice a small dot on the ventral part of the last third segment of a 3rd instar male grub. This is not visible in the female grub. This dot is more conspicuous as the approaches the late 3rd instar stage.
Goliath Beetle Pupation
Pupation is the most crucial step in keeping goliath beetles. The grubs will not pupate without the suitable substrates, and even if they did, they might not survive into adulthood.
It can take around 6-12 months for the grubs to turn pupae. Generally, female goliath beetles pupate earlier than their male counterparts. When you see the grubs start ignoring the food, wandering on top of the substrates and banging the container wall continuously for around a day (that’s why it might topple), you should move it to a new container for pupation.
Fill a 1.5 gal (~6 L) container with loam at least 6” (~15 cm) in depth and place the grub into the container. The goliath beetle grubs require inorganic substrates (which are available in loam) to pupate. If you don’t provide them the suitable substrates, they will continue wandering to look for a suitable place, and may eventually die. The loam used should be half as moist as the substrates used for the younger grubs.
Once the grub feels the substrates are suitable for pupation, it will start constructing a pupation cell. You should stop disturbing your beetle from now onward. Ensure adequate ventilation in the container. Spray a little bit of water as the substrates dry over time to keep it at most half as wet as the initial moisture of the loam. High moisture can kill the pupa.
If you are rearing multiple grubs, you can carefully remove the pupation cell from the loam 2 months after you last saw the grub. Place it together with other pupation cells in a ventilated container. Bury half of the pupation cell into moist substrates (eg. pesticide-free potting soil).
Emergence of Adult Goliath Beetle
The pupae would turn into adults in around 2-3 months. After emerging, the goliath beetles remain dormant in the pupation cell for another 3-4 months before it breaks out from the cell.
Certain beetle keepers will break the pupation cell during the dormant stage. This is because when the goliath beetle attempts to break the pupation cell, the pattern on its back might be scratched.
To do that, first, hold the pupation cell and slowly rotate it in your palm. Pay attention and feel if there is an object in the cell. If you feel something rolling as you rotate the cell, put the cell back and wait for 1 more week. Otherwise, carefully poke a hole on the pupation cell using an ice breaker. Be careful not to hurt the beetle.
Through the small hole you should be able to see the beetle. If it is indeed an adult beetle, carefully peel off the pupation cell like how you peel off the shell of a hard-boiled egg. Note that the pupation cell is quite hard. If it is still a pupa, put the pupation cell back and wait for a few more weeks.
Here’s my recommended supplies that you can consider getting for your goliath beetle. The 10 gal container is for breeding.
Note that I get a small commission when you buy the items through the links in this page. This helps me to maintain the site without incurring additional costs to you.
Handling the Beetle
The grubs and pupae are quite fragile. You can put them onto your hand if you want but be careful not to drop them. They will be severely injured and may die if you drop them! You can also put a koi fish food pallet on your finger and feed them!
Try not to disturb them too much, especially when the late 3rd instar grub is building its pupation cell.
While the adult beetles are protected with a thick layer of armor, you should still be gentle when handling them. You should be able to hold them easily. Always grab their thorax instead of their legs. Their legs are fragile and have spines that might hurt you.
Never forcefully pull the beetles from a surface they grasp because that may break their legs.
How to Deal with Mites?
Mite is an issue with many insect pets, especially goliath beetles due to their diet. Do understand that mites do not just come out of nowhere. If the food and substrates are mite-free, you will not have any mite issues.
If you do encounter mites, dispose of all your substrates and thoroughly clean your container. Hold your grub under a slow running tap and brush it gently to remove all the mites before putting it back to the cleaned housing with new substrates.
Remember to check out our recommended books to learn more about goliath beetle keeping.