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Rainbow Stag( Phalacrognathus muelleri) 

Rainbow Stag Beetles are one of my favourite  beetles. They are bright, colourful, and easy to care for. Go to the care sheet  on this website Rainbow Stag Beetle | TheInsectNerd   if you are new to stag beetle care. 

So, I have also recorded a vlog for you. I ,however, wanted to write a fact sheet to go with it. 

The Vlog link is here :

Breeding Stag Beetles, whether Rainbow Stag or glass stag is relatively simple. We will first go through the steps.

1. Pairing- First, you will need to pair your stag beetles. You need a female and male stag beetle. They need to be placed together in a  medium container with a small amount of  soil for substrate. Why is it a little amount of soil? Well, if there is too much soil,  the female will hide deep inside it, and the male will be unable to find her, and therefore they will not pair properly .  Once the female and male have paired successfully, you need to wait two weeks  for the female to be properly fertile. 

2. Building the Breeding Box: You do not require much to make a breeding box.  You will need a plastic( preferably see-through) box. The box must be deep enough for two medium to large logs to be placed at the bottom.   Why the logs? Well, stag beetles lay their eggs inside wood. In some case, rainbow stags have laid them loose inside the soil, but this doesn't always happen. The logs also make it easier for you to see and collect the eggs.


For box size, I  recommend a  size of around  25 litres. However, you can use  a bigger size if you want. I recommend using two logs. I would say two is a good number of logs, as it will provide two options for the female to lay her eggs. 

For the breeding box, it is crucial to pierce holes in the side, bottom and top of the plastic box to provide adequate ventilation.

The specifics- Things you will need

1. Flake Soil: Flake soil is required for stag beetles and rhino beetles in particular. If any type of soil is used the grubs will become diseased and malnourished. Flake soil is expensive but it is the best quality substrate for beetle grubs and beetle breeding.  There is another substance called Kinishi, but this is very difficult to obtain in the UK.

2 Rotten wood logs ( preferably oak): These must be rotted or rotting logs, the female will struggle to burrow through a fresh one. Also, a good tip is to remove any hard bark to make the job easier for the females to dig through the wood. 

3. Beetle Jelly: for sustenance! The female will be under the soil laying eggs but will still require a form of nutrient. You can use fruit, but I prefer beetle jelly as it lasts a few days, and doesn't attract as many flies as fruit does. 

4. Scissors or a knife: This is to cut the holes in the container to  make air holes. 

The Process- Adding your stuff to the Breeding Box 

1. Place the logs in first:  Remember the logs  must be rotten, otherwise the female will not be able to burrow through it to lay her eggs. I also pour some hot or boiling water clean pests that may be in the log. The log must be left to cool for 24 hours before going into the soil. 

2. Add the flake soil and press with your fist to make it smooth or flatterRemember it must be flake  soil you use. 

3. Move the females: The female needs to be alone in the breeding box. The male beetle needs to be kept separate as they can stress the female out.

4. Put half of the tub on a heat matt:   Part or half of the tub must be placed on a heat mat. The temperature must be around 24 degrees Celsius. However, if it is summer, it will be warm enough, so you would  not have to have the heat mat.

5. Play the waiting game: You must wait for the female to lay her eggs. This can take  up to a month. Remember, you must ensure the temperature is 24 degrees Celsius; rainbow stags will not breed below this temperature. 

6. The Eggs are Laid, Horroah!: The eggs will appear clear, white and very small, so be careful as you go looking for them. I highly recommend that you carefully scoop the eggs out with a spoon, or use gloves or kitchen roll to pick them up as they are incredibly delicate. Some breeders do not separate the eggs, but I like to as when the grubs hatch sometimes the females can become cannibalistic. I also highly recommend that you  separate the eggs and grubs as stag beetle grubs are known to want to nibble each other too!


Picture B: Shows L2 grub. 

Picture A: Shows what the stag beetle eggs look like. 

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