Saturday, 9 November 2013

Jelly for the tropical beetles at home (includes recipe)

It is a massively disputable issue what is the best food for exotic beetles. During my beetle breeding experience I found that beetles are interested in some food more than others.  Sweet, well-ripened fruits could serve as a healthy meal for some beetles. However, knowing what kind of food is the best for your beetles, could be important for maintaining their activity and for a prolonging the life of imagos.  Some cetoniidae, such as large tropical mecynhorynha will live well on ripe banana, other, such as stag beetles will prefer more watery food.  A commercially available jelly for beetles could be a good option at some point of your beetle breeding experience, however, if you have massive numbers of active adult imagos, it could be quite expensive to support  all of them using such food.  Using ripe fruit all the time is also not a great option; firstly they go off  instantly, and secondly you must have them "in stock" all the time.  Plus they may attract a lots of fruit flies, particularly in the summertime. I found it most convenient to use home-made jelly as a fruit substitute, and supplementing beetles' diet  from time to time with fresh ripened fruits, such as sharon fruit, grape or banana. I also believe that most of the stag beetles have relatively short lives and their digestive system is not well-developed. That's why they may require mainly watery food. Currently I am using a jelly recipe which I slightly modified from recipe found somewhere on the internet. I am using agar-agar as a jelling agent, it is available on ebay; it's cheap and will cost pennies per substantial amount of jelly. Agar agar is obtained from algae, in contrast to common jelling agent gelatin that obtained from animal tissues.  I never tried to replace agar with gelatin, but I believe that it is possible.   

For my jelly  (about 350 ml in total) 
I use following ingredients:

1) 1 ripe banana, mashed

2) 40 g dark brown sugar

3) 1 teaspoon of honey

4) 1/4 teaspoon of agar-agar

for stag beetles or 1/2 teaspoon of agar for cetoniidae and dynastinae

(agar could be of different strength, so you may need to determine it's amount by yourself)

5) 250 ml of water

Combine all ingredients in one pan, bring it to boil on small gas, boil for 1 min and pour it into a jar.   It can be stored in the jar in a fridge for weeks and has beetle container life from 3 to 5 days. I spoon it into plastic milk bottle cups and feed it to my beetles like that. If you feel that the jelly consistency is a little hard for your beetles, you can put a few drops of warm sugary water on the top of the jelly, it will make it much softer and watery in minutes. 

To see more photos of beetles, please visit my flickr page at

You can also contact me via regarding any related issue and availability of beetles.

Tuesday, 15 October 2013

Sexing flower beetle (cetoniidae) larvae

Sexing flower beetle (cetoniidae) larvae, such as mecynorrhina ugandensis, protaetia or goliathus is not very difficult, however, requires some practice. It is much easier when larvae are reaching their third (L3 stage). In smaller larvae, such as at their L2 larval stage, finding the "right spot" is quite difficult because of their size and because of their mobility:  small larvae are normally very active:) With some practice anyone can do it. Determining the sex of the larvae by the size of its head capsule is not reliable, simply because the smaller larvae of the same age will have the smaller head capsule, irrespectively whether it's male or female.  It is best to see it in larvae which are clean of dirt and debris. On the bottom (ventral) side approximately in the middle of the last abdomenal segment in males of cetoniidae there is a small black slit/spot which is a part of  such-called "Harold's organ" (please see the photo of the L3 male larvae of the Mecynorrhina ugandensis, on the left). The spot may often look like as a hair root spot, apart there would not be any hair growing from it. The bigger larva is the bigger the size of the spot will be. That's why it is more easier to determine the sex of bigger larvae, which also normally less mobile than smaller larvae. Females (photo on right) do not have such black spot. 

Sunday, 22 September 2013

Giant flower beetles mecynorrhina torquata immaculicollis/ugandensis care

General requirements

Temperature: 18-26C; 23-25C day and night is optimal
Humidity: high for both larvae and adult beetles.  Less humid for pupae.
Light: 12-14 hour day light/daylight bulb for adults.
Breeding tips on my Youtube channel


     Larvae of giant flower beetles (Cetoniidae) require for their development rich organic wood derived substrates such as mulched well-decayed leaves (normally from hardwood trees such as oak or beech) which could be mixed with some mulched soft rotten wood  from the same trees.  They also grow well on just mulched soft rotten wood or artificially rotten hardwood sawdust (flake soil).  No conifers can be used, as they are toxic for the larvae. Part of the substrate needs to be replaced regularly once the most of it is consumed. Larvae of the similar size can be kept together, however, some breeders recommend to keep them separately, suggesting the possibility of the cannibalism. However, in my experience I have never observed any cannibalism in similar size Mecynorrhina torquata immaculicollis/ugandensis larvae which were kept in groups. However, make sure that the larvae are not to crowded, because they may bite each other accidentally.  Larvae need to be kept in a closed plastic container, with air access holes in its top or upper part of the box sides.  Normally a ~1.5-2 liter container is needed for one L3 stage giant flower beetle larva. To improve larvae's growth many hobbyists use protein rich supplement (e.g. dog or fish food pellets).  As an example 1 pellet of Bakers Meaty Meals (1 kg box from supermarket will last for generations of beetles) is placed at the bottom of the container per one L3 larva per week.  If pellet is left uneaten then the food supplementing can be skipped.  Well developed larvae should normally reach 30-40g in weight before they get into the a pupation stage.  It is always useful to weigh larvae every couple weeks to ensure that they're putting on weight. Inexpensive jewelry watches, which can be bought cheaply on eBay, are great for this purpose.  During pupa period (6-7 weeks) the larvae should not be disturbed as pupa may die inside pupal chambers or it may lead to the deformed imago which normally will die shortly afterwards. Both pupae and freshly molted adults are very sensitive to mechanical stress.  It takes several days for larvae to construct pupal chamber out of substrate. With some care fully formed pupal cell can be gently removed and transferred into another container. 


After pupae turn into adults the beetles stay inactive in their cells for 3-5 weeks. The beetles should not be disturbed first week, when their exoskeleton is hardening during this time. While dormant, the  beetles do not require any food as I understand that they still finish their development.  After they become active (start moving actively in search of food) they can be fed on any sweet ripe fruits.  Ripe banana is recommended, as it contains a significant amount of proteins. Commercially available beetle jelly is considered as a very good food for these beetles due its high protein content and because of it’s long shelf life and resistance to moulding. A simple version of the home made beetle jelly can be found here ( Breeding container is normally a plastic box (20-30l) with about 15-20 cm of top soil at the bottom mixed with about 5-10% of rotten leaves and mulched decayed wood. Healthy males are very active and normally will chase females even underground. Mated female will lay eggs into soil.  You can start checking for eggs after about/ every 3-4 weeks. After female died soil needs to be carefully inspected and all larvae and eggs transferred into the larvae rearing boxes. Food needs to be present in the container all the time as it normally results in more eggs laid by beetle females.

Monitoring the development of a larva with a jewelry scales.   Mid L3 larva of Mecynorrhina torquata ugandensis.

Pupal cells of Mecynorrhina torquata ugandensis. One opened cell at the bottom has imago beetle which can be seen through the whole.

Please visit my youtube channel, it has plenty tips about raising giant fruit beetles.

You can also contact me via
regarding availability of these beetles for sale or exchange.

Cyclommatus Metallifer

A Stag beetle, Cyclommatus Metallifer, family Lucanidae 

The origin of this stag beetle is jungles of certain islands of Indonesia (Sulawesi, Peleng, Sangir,  Bangkulu, Sula, Bachan, Halmahera and Morotai).  It is even considered that the different population of these islands are of different subspecies.  The males of these beetles can reach 9 centimeters (reported record is of 100 mm) in length, of which more than half are mandibles  equipped with spines which male uses in battles with other males to win female's attention. Females, in turn, are rather small and rarely exceed 3 centimeters in size. The males of these beetles have beautiful metallic-brown colouration which at right light angle appears as a golden-brown one. These beetles are quite popular in beetle breeders as well as with amateur hobbyists because of their attractive looks and by easiness in care.  The development from an egg to imago (adult beetles) can  take 9-11 months, but from my experience this term could be shorter if grubs are kept at higher temperatures. The larvae of these beetles are not cannibalistic so they can be kept together in larger containers under condition that sufficient amount of feeding substrate is provided. It is also reported that fungi based kinshi substrate bottles are not really suitable for rearing larvae of these beetles and fermented wood flake substrate needs to be used.   

A major male of Indonesian stag beetle   Cyclommatus Metallifer, captive bred almost 80 mm.

Rearing and breeding tips.  

Food for imago

These beetles seem do not like any "harder food" and any liquid food is more acceptable for them. In my experience they prefer liquid food, such as liquid from juicy ripe fruits such as sweet oranges or clementines even to popular beetle jelly, available at various pet shops. A watermelon and a melon, any sweet apple,  half of a grape or a sharon fruit will be also fine.  Just mush top of the fruit slice with a teaspoon to allow juice to come out of flesh of fruits. This seems help beetles to obtain the juice that they needed.  Try use some sort or tray for the fruits, and do not put them directly on a substrate as it will accelerate their moulding. I am using plastic milk caps for this purpose. Lightly moulded fruits are still fine, as they still have some sugars in them and beetles still enjoy them.   To obtain juice from fruits beetles piercing the fruit's flesh with their “feathery mouthpart bits” which are called galeae in the scientific language. I normally also put a few drops of water sweetened with brown sugar or honey. This seems stimulate beetles to start feeding. Sometimes,  initially it  requires to put a beetle on the top of the food encouraging it to feed. Although the discussions between expert breeders whether some imago stags need protein supply in their diet are not conclusive, you may still want to increase the protein content in their diet. I would not recommend adding any "yogurt"; as using plain ripe banana mash will perfectly work for this purpose.  Banana has relatively high protein content (up to 6%) so banana well mashed with some still water sweetened with brown sugar or honey will work just fine.  

After you have obtained a pair of these beetles it is the best if you can visually confirm that the pair has mated.  This can be done by placing male and female into a mating container which is a small clear plastic box with some substrate and a few pieces of wood which would allow beetles to hang on it. This allows to observe the mating easily. Best way is to put a hungry female on top of a fruit slice and while she is feeding on it, gently place a male on top of her. Male needs to be well-fed  beforehand, otherwise meal would be his first and only goal:).  Female will eat and go into a hide and male still will be busy with his meal:) Sometimes female is not interested in mating, if it is not mature enough or possibly because she feels that the mating box is not suitable for her to lay the eggs. If mating does not occur for some time, the female can be placed directly into an egg laying container with 1 or 2 males in it. In my experience the dominant male normally takes place near the provided food, and often the one who lives longest. Males will also often fight for the dominance, which often leads to a premature death of a weaker male.  

Egg laying setup. 
Female of this beetle will lay eggs into softer parts of the dead wood collected in the forest.  In my experience the female would prefer oak to other kind of trees, but beech and other trees such as ash or poplar could be also fine for egg laying.  It is considered that wood for the majority stag beetle species should not be very hard and should not be very soft too. You should be able to scratch it easily with a nail, but is should not be very hard.  With these beetles I have been finding eggs even in substrate, but not in logs.  female would chew a 1-5 cm hole long hole about 1 cm deep and fill it with chewed pieces of wood until it forms a clump. The ovum normally is in the middle of the clump.  My setup is normally a 25-30L plastic box, filled with garden soil from the bottom (10 cm pressed hard), then 2-3 logs (8-15 cm diameter, 10-30 cm long ) all covered with foul white wood mixed with soil so the substrate just cover logs.  The humidity is high, with a few small holes in the side of the container. Fresh food needs to be placed  regularly to keep female active and make her lay more eggs. Female usually would come out at night, unless she is very hungry.  Optimal temperature is around 22-25 C, however, females will lay eggs even at 16-18 C.

Rearing larvae

After about 3-4 months logs are carefully removed and inspected.  The female most likely will be dead by this time. Logs are carefully split with hands or using a screwdriver and grubs are removed.  Grubs are placed into containers with fermented wood individually, although they can be kept together and separated when they reach late L3 stage. Larva of this beetle species are not cannibalistic and it was reported of successful raising several larvae until imago in same container. I usually mulch original wood logs where larva initially lived and mix it with fermented wood flakes (30/70%), by this transferring some beneficial bacteria that helps larva to digest cellulose.  

L2 Cyclommatus Metallifer larva in split log. Logs needs to be split carefully and larva needs is traced by by following the holes in he wood. Also some larva may leave in the substrate of the breeding container, so the substrate also needs to be checked carefully. Please note shape of the last segment characteristic for various stag beetles (Lucanidae) species

Clear deli cups 0.3-0.6L is convenient for this purpose, as they allow to observe larvae's activity. Grubs tend to eat substrate close to the sides of the containers so it helps in checking on their development and providing food supplements. If you want to obtain bigger adults, some high protein food supplement such as dog food needs to be provided. I use Bakers Meaty Meals chunky pellets,which are relatively dry but soft and 

  they are not getting mouldy very quickly compared to fish flakes or some other additives. Often larva would not eat a pellet, unless it is placed right in front of it. I make hole in substrate with pencil and place about a quarter of the pellet next to the larva. After about 3 months about 50 percents of the substrate is replaced with fresh fermented wood. Depending on the temperature and conditions it may take as little as 8 months to obtain imago of the beetle. The larvae normally pupate close to the side of the container, so it's activity could be observed. In my experience, I had much higher rate or survival during molting to imago if pupa transferred into the artificial pupa chamber which could be easily made at home (I will illustrate this in a future post).

Female (left) of the Cyclommatus Metallifer is chased by the male (right)

To see more photos of beetles, please visit my flickr page at

You can also contact me via
regarding availability of these beetles for sale or exchange.

Wednesday, 19 June 2013

What lives in your plant pot?

Just a few days ago I found rose chafer, Cetonia aurata, buzzing in our bathroom. Although I have some cetonia aurata grubs living in my beetle cupboard, it is still long time before they turn into adult beetles. The window was closed so the beetle could not come from garden. Then I saw some some debri from orchid pot scattered on a window sill, and after closer inspection I found a hole in the soil in the pot. The beetle must have come out of the plant pot! I have changed substrate for this orchid about 2 years ago, so all this time the grub of the beetle was living and growing there!

Here are some photos of this wonderful beetle!