Sunday, 13 September 2015

The rose chafer, cetonia aurata in the garden.

The underneath photo of the rose chafer, cetonia aurata, female 

Although it is considered that the rose chafer is widespread in the UK, I have never seen one in nature feeding or flying. Some photos found on internet showed the presence of these beetles in relatively close places, mainly big parks, such as Richmond Park. So I assumed that their habitat in London is mainly associated with woodland and park areas. However, about 3 or 4 years ago I left a big plastic box that I used for breeding of my beetles outside in our back garden; the box was filled with some garden soil mixed with rotten wood and leaves. The box was not covered and stayed outside for about 6 weeks. When I decided to reuse it, to my surprise, I found about 40 small larvae in the soil with a female of the rose chafer on the top the soil. This suggested that this female, which was flying in the area, found the box with substrate rich in decaying wood and leaves and decided that it is acceptable for her offspring. 

I normally remove quite a lot of the used beetle larvae substrate from my boxes and I usually "discard" it into the vegetable patch in our back garden. This used substrate apart from larvae's frass still contained a significant part of uneaten material such as rotten wood and decayed leaves. This spring I was digging soil for the tomato patch and discovered 5 larvae similar to appearance to rose chafer larvae. We have plenty of summer chafers (amphimallon solstitiale) flying in spring and summer in our garden, so automatically I assumed that these are the larvae of this species. However, I decided to keep these 5 larvae and put them in the box with some decayed leaves. About 2 month ago these larvae pupated all together and later emerged as 5 beautiful rose chafers, 2 females and 3 males, which seems almost a perfect ratio! I made and break with these species about couple years ago but it seems that I will be starting with them again.   The males of the rose chafers, as many other flower beetles, have a distinct "invagination" on their abdomen, which often appears longitudinally divided (please see the photo below)  

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Thursday, 18 June 2015

A brief (and hopefully) comprehensive guide to the substrates for rearing larvae of flower, rhino and stag beetles

When I was starting with  beetles, I had trouble with finding info about what kind of substrate is suitable for different sorts of beetles. The things were further complicated by information obtained from various beetle "keepers" enthusiasts which used different substrates to raise same species of beetles.  Since I am often being asked similar questions, I have decided to break down this information in one post. This information is mainly based on my own knowledge/experience and presented in a very shortened generalized form, and thus may not be suitable for some specific beetles. However, most likely it will suit very common groups of beetles and the post could particularly be helpful for beginners.
There are 3 most popular groups of beetles which are kept by breeders. 
These are flower beetles (family of scarab beetles, Scarabaeoidea, subfamily Cetoniinae; such as Pachnoda ssp, Dicronorrhina ssp or Mecynorrhina ssp), rhino beetles (family of scarab beetles, Scarabaeoidea, subfamily Cetoniinae, Dynastinae; such as Megasoma ssp or Dynastes ssp), and stag beetles (family Lucanidae, such as Lucanus ssp or Dorcus ssp). 
The development of larvae of all these groups in nature is usually attributed with decaying organics, mainly rotting wood.  However, in captivity many breeders often grow major adults using leaf litter or leaf litter mixed with decayed wood as the main substrate. It is also generally accepted that the simplest substrate is the one consisting of decayed leaves and wood of hardwood trees such as oak or beech. Therefore "the basic" substrates are:

1) Pure leaf litter. 

This substrate normally consists of a lower layer of partially disintegrated decayed leaves which could be mixed with some woodland top soil (humus).  The leaves should be well decayed, not freshly fallen, preferably at least 1 year old. In such substrate, hard parts of leaves are pre-digested by microorganisms. The presence of soil in such substrate could help distributing the moisture and developing of the beneficial bacteria, particularly if a container with larvae is not very deep. 
This substrate is good for any flower beetle larvae, although some species may require some additional protein supplement during their later stages, e.g. starting from the late L2-early L3. Some beetles such as goliath beetles, starting from L2 stage require mainly high protein food, and almost do not consume any other substrate. 
This substrate is also used by many breeders for raising larvae of some rhino beetles, particularly of megasoma ssp.  

2) Pure decayed (rotten) wood.
This is normally pure rotten wood from hardwood trees (oak or beech are always preferred), which ranges from soft white to brownish/black in colour and either soft or just soft, but not hard wood. The soft wood is that kind that you can easily brake and crumble it with your hands, the "just soft" wood is that kind that it is difficult to brake it with your bare hands, but it would be very easy to hammer the nail in. This wood is usually the result of part of the tree being damaged by fungi and in such wood the most of the lignin is destroyed either by fungal and/or bacterial activity. The softer wood can be used for rhino beetle substrate and for oviposition of majority stag beetles such as lucanus, although the "just soft" wood could be also good for the some other stag beetles such as dorcus or phalacrognathus. Both types of wood could be mulched and used as food for both stag and rhino beetles right away, although the majority of stag beetles may prefer the harder ("just soft") decayed wood.  Since the nutritional value of freshly decayed wood is not exceptionally high, some additives such as soy protein powder or dog food pellets are often recommended, particularly at later stages of the larvae development. The decayed wood which you can find inside of large dead oak trees and which has pure brown colour and feels like a cork is not suitable, as in such wood all nutrients such as cellulose are already disintegrated.

3) Decayed wood and leaf mixture.

This is normally the mixture of mulched decayed wood and leaf litter mixed together. Stag beetles normally do not grow well in "leafy" substrate and require decayed wood or more advanced substrate for their growth.  This substrate, however, works quite well for many rhino beetles, particularly with some additional protein supplements starting from the early L3 larvae. In my experience the early larvae of many rhino beetles grow better in decayed leaf substrate with only little wood in it; then the bigger the larvae may require more wood as they grow. I normally end up with like 40% of the wood in the substrate for the late L3 larvae. All bigger chunks of decayed wood (ideally a log) need to be placed at the bottom of the container so the larvae could easily access it, if they would require more wood.   

Advanced substrates.

1) Fermented wood (flake soil)
In this substrate the harder wood components such as lignin are pre-digested by micro fungi and bacteria. The substrate is normally made using hardwood sawdust/shaving, baking flour/bran, often larvae frass and sometimes yeasts. The yeasts develop "feeding" on carbohydrates of the additives bran/flour and products of the fermentation at the beginning of the process and it is believed they are closely associated with some fungi which digest harder components of the wood. Yeasts are not necessary if larvae's frass is added as an additional source of favourable microorganisms and nitrogen. Ultimately, the process leads to exposing cellulose of the wood and at the same time enriching of the substrate with nitrogen-rich biocompounds/microorganisms which later are assimilated by the larvae. The "indoors" process is most effective at the temperatures above 20C and in bigger volumes and requires often mixing of the substrate. At 25C using air dried oak sawdust it takes about 2 months to obtain a good substrate for stag beetle larvae  or 3-4 months for rhino beetle larvae.  The substrate can be made oudoors in well ventilated capacities, e.g. woven bags, preferably in direct contact with the soil.  It allows a massive influx of bioactive microorganisms from soil which together with efficient oxygenation provides faster wood degradation and does not normally require regular mixing, heat or addition of the yeasts. The ready substrate could be from dark brown to black in colour when moist and should not smell ammonia or alcohol but have rather "earthy" smell. As the composition and degree of wood degradation of fermented substrates obtained from different sources may vary, it is always wise not to replace the existing larvae substrate with a new one right away completely, but to introduce the new substrate gradually especially for slow eating larvae such as hercules beetle.  The advantage of such substrate is a high availability of the remaining cellulose and nitrogen-rich bacteria/components which promote the larval growth. The fermented substrate for rhino beetles can also be used for flower beetles, although I personally did not find much difference in development between flower beetles larvae growing in fermented wood flakes and in the leaf litter substrate.

"Stag beetle grade" fermented wood flake soil

"Rhino and flower beetle grade" fermented wood flake soil

2) Kinshi
Kinshi is the well developed mycelium of fungi, which is normally grown on oak or beech sawdust/woodflakes. Due to the high nutritional value kinshi represents an excellent substrate for various beetle larvae, particularly some stag beetle larvae such as dorcus or phalacrognathus. Kinshi  can also be given to rhino beetle larvae but only as a part of the substrate. The woodflakes, mixed with some additives such as baking flour, are sterilized, and the mushroom spawn is introduced. It normally takes at least 2-3 months for spawn to completely colonize the substrate. In ready to use kinshi the fungus colonizes almost all free space of the container and the substrate should have a  bright white colour. The most common fungus used for this purpose is king oyster mushroom, pleurotus eryngii,   perhaps because its mycelium develops much quicker than other similar mushrooms. This allows fast colonizing of the substrate, thus decreasing the chance of the  contamination with mold. Another fungus, which is important for the development of some stag beetles such a Allotopus ssp, is turkey tail fungus, trametes versicolor, is often used for making kinshi. The biggest challenge of the kinshi production, particularly the one at home, is a contamination of the substrate by mold which can easily put off  any breeder from making it:(    

kinshi at early stage;  various degrees of colonisation of the substrate can be seen

ready to use kinshi

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Tuesday, 16 June 2015

Goliathus orientalis preissi broken pupal cell and artificial puaption chamber

Just before constructing a pupal cell, a goliath beetle larva enters "the wondering phase". During this time the larva comes to the top of substrate "wondering" around, and trying to escape its current container. Such larva needs to be placed into a new box containing the mixture of peat and sand, where the larva will later construct its pupal cell. Sometime ago, I placed one of my golaithus orientalis larvae into such box and forgot to label it. Then later when I thought that the box had no larvae inside I decided to use it for another wandering larva goliath beetle larvae. The result was not very nice, as the first larvae finished its cell already and I accidentally broke it while preparing the substrate in the box for the larva N2.  The larva inside of the cell was still pretty active, and I was hoping that it will have some energy to repair the cell, although the damage was massive:(.  Normally such cell damage in large flower beetles such as Mecynorrhina results in larva leaving the cell and dying eventually, as it would not have enough to build a new pupal cell. I left the larvae in the broken cell as it is, and luckily one month later I discovered that it did not leave the cell. I transferred the larvae into the artificial pupal cell made from floral foam and about 2 days ago I discovered that it turned into a gorgeous female pupa! Please see the photos below.

Thursday, 30 April 2015

Identification of the larvae of common European Lucanidae

There are just a few species of the beetles of Lucanidae family found in Europe, with the biggest one being European stag beetle, Lucanus cervus cervus. The species of this family which can be found in the United Kingdom are Sinodendron cylindricum (sometimes called Least Stag Beetle), Platycerus caraboides and Dorcus parallelipipedus (Lesser Stag Beetle). Apart from the European and lesser stag beetles, the other two do not look much as stag beetles since their males do not develop impressive mandibles. Although the larvae of the Lucanus cervus is considered polyphagous and often found feeding on decaying roots of garden trees or rotting fence posts, their typical food source is normally associated with decayed wood of hardwood trees such as oak or beech. Despite the fact that the stag beetle's larvae occasionally found above the ground, e.g inside of heaps of decayed woodchips,  their larvae is usually live underground in their natural habitat. Similarly, sinodendron cylindricum larvae is also usually found in decayed oak or beech wood.  In contrast the lesser stag beetle larvae also can be found in decayed wood of various deciduous trees, often in logs above the ground and often in big numbers. In our South London area I often find these inside of decayed poplar logs above the ground, and normally adults beetles can be found in the same rotten log with the larvae. 

The least stag beetle, Sinodendron cylindricum, despite that it belongs to the lucanidae family, looks more like a rhino beetle.  The photo shows a (dead) female of the species which was found in Mitcham park in South London.

The lesser stag beetle, Dorcus parallelipipedus male looks as a smaller version of the minor male of lucanus cervus cervus.

Obviously it always interesting to know what lucanidae species is the larvae that you found.  However, because the larvae (particularly the smaller one) of all lucanidae look pretty much the same, it is very difficult to determine to which species the larvae belong to. This is particularly applicable for the dorcus parallelipipedus and lucanus cervus cervus, as the late L3 larvae of the DP could be as big as early to mid L3 larvae of the LCC. Considering the fact that DP is an abundant widespread species and normally live in the same areas as LCC this could be quite an issue.  However, apparently it is still possible to identify the larvae of the common UK's lucanidae by comparing the shape of their last (terminal) segments. Here I came across the diagram published by T.E. Leiler in 1950 which could be useful:)

The diagram below shows the caudal and ventral view of the last segments of common lucanidae larvae

Leiler, T.E. (1950) Bestimmungstabelle der schwedischen Lucanidenlarven (Coleoptera). Opuscula Entomologica, 15, 157–160. 

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Sunday, 25 January 2015

The Western Hercules Beetle, Dynastes Granti, breeding report

Some time ago I purchased 3 late L3 larvae of Dynastes granti as an impulsive buy:). One larvae died in a few days and the other two successfully molted into the pupae after the month or so. I did not check their sex initially, so was a bit disappointed as they both turned out to be females. By the time they eclosed into adults, it was winter here in the UK and purely out of pity I purchased the male from Asia for something like 5 times its normal "seasonal" price. Luckily, we had a  few relatively warm days here, during which he arrived safely. Here is the brief breeding report.

Setup and adults:  A 40 litre  plastic box filled with garden soil/peat/rotten oak wood and leaves mixture.  Wood and leaves were mulched well into small particles and mixed with soil (garden soil/peat mixture), with 1:9 ratio. Bottom 15 cm layer was pressed firmly. Top of the soil was covered with small logs, sticks and leaves. I used my beetle jelly recipe ( ) and ripe banana sprinkled with diluted honey for adults,  which they loved and consumed lots of it. The temperature was 25C day and night. The box had only a few small holes, so the humidity in the container was high all the time. Once the females became active they started to come out and feed. The male was guarding food and and stayed close to the feeder all the time. 

Eggs: I made the first dig after about 8 weeks when the females became active and started feeding. I dug up 50 eggs. The majority of the eggs were deposited very close to the bottom of the container, some of them were literally at the plastic bottom of the container.  I rearranged the soil in the box and let the beetles into the container again. 
After another 6 weeks when the male died and the food was not touched for a several days I made another dig and discovered that both females were dead and removed another 38 eggs from the soil. I was pretty satisfied with my results obtaining 88 eggs from two females. Interestingly, it may take ages for eggs of dynastes granti to hatch; first eggs started to hatch after about 8 weeks, while some hatched only after 6-8 MONTHS!!! Some of my larvae were solid L3, when the late eggs just hatched.  

Larvae:  The larvae of the Western Hercules beetle turned out to be pretty hardy, similarly to the Eastern Hercules beetle (dynastes tityus) larvae. I tried both oak rotten wood and decayed oak leaves substrates and they were doing just fine. Moreover, I even switched the substrate during the development of the small group of larvae, and observed that it did not affect their development drastically. I also had very low die out percentage of the larvae; may be just one or two out of the whole lot.   

I found the breeding and rearing of these species quite easy. The only pity is that such beautiful beetles do not live long as adults, just about 3-5 months.