Dorcus Hopei Binodulosus (Ookuwagata)
These beetles can be found around Japan. The pair above are from Saga Prefecture on the island of Kyushu. Japanese people call them "Ookuwagata," which is literally translated into English as "large stag beetle." They are the most popular Japanese beetle in Japan due to their large sizes, mandible shape, life longevity, temperament and ease of breeding. Japanese people also find the single tooth on both sides of the mandible attractive.
These beetles can easily live for 3 years. They have also been known to live up to 5 years if they are allowed to hibernate in the winter months. They are not an aggressive beetle. If they are handled, they generally just open their mandibles, pull in their legs and remain motionless. However, if they are provoked, they will clamp onto your fingers, which is extremely painful and will draw blood.
These beetles can easily live for 3 years. They have also been known to live up to 5 years if they are allowed to hibernate in the winter months. They are not an aggressive beetle. If they are handled, they generally just open their mandibles, pull in their legs and remain motionless. However, if they are provoked, they will clamp onto your fingers, which is extremely painful and will draw blood.
Male Dorcus Hopei vs. Female Dorcus Hopei
Both males and females are a jet-black color.
Males can reach a size of 80mm long and have large mandibles. Their mandibles have a tooth on each side that protrudes inwards. They use these mandibles to fight with other males over food and mating rights. Their bodies are wide and flat. The females have much shorter mandibles that are used to break down wood when laying their eggs. Females can reach a size of 48mm long. Their elytra are shiny and have many small dots that join together to make lines down its wings. |
Caring for Dorcus Hopei Stag Beetles
Dorcus Hopei beetles are not very active beetles, so they can be put in a medium-sized container, such as the container above. This container is very good for keeping out fruit flies and also keeping in moisture. In summer, since mites can be a problem, it is best to use a matting that is made from a coniferous blend. This matting should be kept moist. Water should be mixed with it if it becomes a little dry.
Dorcus Hopei beetles need pieces of wood to hide in or under and to walk on. The male will spend most of his time hiding in his piece of wood, like the picture to the right. Females will spend most of their time under the pieces of wood placed in their container. You can use wood that you find in the wild, but you will need to heat treat it to kill off other insects. Many wood pieces sold in shops for beetles also act as jelly holders. The jelly sold in Japan is specifically made for beetles. They come in a wide range of flavors, but a jelly that is high in protein, like the jelly above, is believed to help beetles live longer. However, these beetles will also eat fruit, such as apples. Never use fruit that has a high water content, such as watermelon. |
It is best to keep the male and female in separate containers until you are ready to breed them. Never put two males in the same container, as they will constantly fight for food and mating rights. Japan has a big beetle fighting culture, but there is always a chance that the beetles will get seriously injured. Dorcus Hopei beetles are quite expensive. Paying 10,000 yen for a pair of Dorcus Hopei beetles with a male that is over 70mm long is considered normal. It is a lot of money to spend to have it injured in a fight. Common injuries include loss of limbs, antennae or scratches on its body. These injuries will significantly reduce its life expectancy.
When the temperatures become lower, they will want to hibernate. In Japan, this happens around November. They will hibernate until about April. When the temperatures rise, they will begin to eat beetle jelly again.
Their needs in the colder months are very limited. You just need to fill up a container with humus. Make sure it is a little moist and then keep it In a cool part of the house. They don't need any food during this time. |
If the temperatures are too high, the hopei beetles won't hibernate. If you want them to live long lives, it is advised to let them hibernate in the winter months.
Breeding Dorcus Hopei Beetles
When choosing a male and female for breeding, you should make sure that they are both from the same area or prefecture. You will find that breeders do not like to mix beetles from different parts of Japan. For example, they will not breed a beetle from Yamanashi Prefecture with one from Saga Prefecture. They will want to breed a male from Saga with a female from Saga.
Also, the size of both the male and female should be considered. You should pair a male with a female that is between 20mm and 30mm shorter than the male. If the size difference is too great, it can be difficult for them to successfully mate, making the male become frustrated with the female. The best temperature for breeding is between 21 and 26 degrees Celsius. In Japan, the best time to pair Dorcus Hopei beetles is between May and July. Both beetles should be 6 months old or older. Dorcus Hopei stag beetles less than 3 months old are not ready to reproduce. |
When the temperature is between 21 and 26 degrees Celsius, put the male and female together in the same medium-sized container. Place pieces of wood around the container and add some beetle jelly. It can be a good idea to introduce the female a few days after the male. Wait until the male is hiding and put in the female. This may reduce the risk of the male becoming violent with the female. However, generally speaking, male and female Dorcus Hopei beetles do tend to get along quite well.
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There may be some occasions where the male and female are incompatible. If this is the case, separate them before one gets injured. If they get along fine with each other, leave them together for 1 to 2 weeks. In this time, they should hopefully mate. It can be difficult to catch them in the act, as they will spend the days hiding and will only become a little more active at night.
While you are waiting for them to mate, you can prepare another container where the female can lay her eggs without being disturbed by the male.
While you are waiting for them to mate, you can prepare another container where the female can lay her eggs without being disturbed by the male.
1) The female will only lay eggs in wood. In pet shops you can buy oak wood specifically for egg laying. The wood should have a diameter of 8 to 10 cm. Select 2 to 3 pieces, as females prefer some wood over others. Female Dorcus Hopei beetles like wood that is a little hard.
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2) Soak the pieces of wood in water for 3 to 6 hours. You can use the large container that you will put the female in. Simply fill up the container with water and add the wood. Turn the lid over and place a heavy object on top, such as a brick, to keep the wood submerged in the water.
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3) Remove the pieces of wood and use a flathead screwdriver to remove the outer brown bark and the orange part just under the bark.
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4) Allow the pieces of wood to dry for a few hours under the sun. It is fine if the wood is still a little wet when you are ready to use them.
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5) Use your fist to compact humus suitable for stag beetles in the large container. It doesn't need to be expensive humus, as Dorcus Hopei beetles will not lay any eggs in it. Make sure the humus is moist, but not dripping wet.
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6) Place 2 or 3 of the oak pieces on top of the humus. You may find that the female will not like one or two of the pieces, but hopefully she will find at least one suitable for her to lay her eggs in.
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NOTE: In step 9 above, the photo shows the male also being put into the container with the female. You can do this if you didn't pair them beforehand, but you may find the male will get in the way of the female when she is trying to lay her eggs.
After you have left the female in the egg laying container for 1 month, you can remove her and put her back into her original container. You should find that she has used her mandibles to break down parts of the wood. In the little holes she has made, she should have deposited an egg. You may or may not be able to see the eggs.
Don't disturb anything yet. Just wait for another month for the eggs to hatch into larvae. If you interfere with the eggs before they hatch, you may find that they won't hatch. The key is patience. There will be occasions where the female won't have laid any eggs. It does happen and this is very disappointing. If this is the case, you will need to try again. Reasons for this happening include the female not liking any of the oak pieces put into her container. Remember that Dorcus Hopei beetles do like wood that is slightly on the hard side. Perhaps the temperature was not in the right zone. You may find that the male and female also weren't able to mate before transferring the female to the egg laying container. |
Caring for the Larvae
After waiting for a month, you can start to carefully look through the wood. Seeing frass is a good indicator that larvae are in the wood.
If the wood is hard, you can use a flathead screwdriver to carefully open up the wood to reveal the larvae. The larvae may be in slightly different stages of development, depending on when they hatched. In the setup I did above, I found 9 larvae in the wood. |
In Japan, there are contests to see who can make the biggest ookugawata or even the most beautiful ookuwagata. People who breed Dorcus Hopei stag beetles use kinshi bottles. "Kinshi" means hypha, which is the structure used to make fungus. When larvae feed on this, they can become much larger than if they were left in the oak wood. However, using kinshi bottles can be quite costly, especially if your female laid lots of eggs.
Each Dorcus Hopei larva will go through three to four kinshi bottles before it pupates. It is best to put the larvae in a 500 to 800cc bottle after you remove it from the egg laying container. Approximately 3 months later, you will need to transfer the larva to another kinshi bottle that is between 800 to 1500cc. Another 3 months later, you will need to do the same thing. In some cases, you will need to do it a fourth time. The most popular kinshi bottle is called the G-pot. Using kinshi bottles is very easy and requires little work to take care of. |
Use a spoon to dig out the top of the 500 or 800cc kinshi bottle. You can discard this part.
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Use a spoon to add the larva to the top. It should dig its way in. Leave it for about 3 months.
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When 60 to 70% of the hypha has been eaten, you should move the larva to a new kinshi bottle. This will maximize larvae growth.
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Move the larvae to a larger kinshi bottle. The one above is 900cc. To make large males, larger kinshi bottles are better, but they are also more expensive.
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The G-pot stout is a wider type of kinshi bottle. They recommend leaving it this way, as shown in the photo, for a few days while you wait to see if the larva can enter the bottle.
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After a few days, you can turn the G-pot stout the other way. Check it every few days to make sure the larva stays inside. You should be able to see the white hypha being eaten within a few days.
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If after a month or so you haven't seen any hypha being eaten, the larva may have died. This sometimes happens.
If you can identify the larva is a female, you can just keep them in kinshi bottles that are up to 800cc. When looking at the larvae which is either at the second or third instar stage, females have a yellowy area. Males don't have this yellow part. Males should be kept in 1200 to 1500cc bottles if you want them to grow large. Keep changing the kinshi bottles once 60 to 70% of the hypha has been eaten. The last change should be made mid April if needed. However, refrain from changing bottles in May, as the larva will soon become a pupa. When you change kinshi bottles, it is nice to weigh the larva and record this information. On the larger kinshi bottles, there is often a space to write when you changed bottles and how heavy the larva is.
You can often predict how big the beetle will be based on its weight. The larva pictured to the left is only a few months old, so it still has a lot of growing left. A male larva nearing pupation that weighs about 20 grams will become an adult that is about 70mm long. |
In May and June, the larva will start to make a pupa chamber. It will remain a pupa for about a month. If you are lucky, you will be able to see the pupa through the kinshi bottle. Try not to move the bottle too much at this stage, as it is a very delicate time for the beetle.
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Once the beetle becomes an adult, you should wait at least two weeks before even attempting to take it out of the kinshi bottle. You will find that if it is left undisturbed, the beetle will remain in its chamber for a longer period of time. Some sources say you should wait at least one month before removing the beetle.
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This ookuwagata male is 65mm long. It is not quite as big as his father, which is pictured at the top of this page. His father was 72mm long.
The position of the tooth on the mandibles depends on the size of the beetle. The smaller the beetle, the closer the tooth is to its head. The tooth on this beetle is slightly lower than that of its father. |