Egg-laying problems in palearctic Cetoniinae
Short post on some breeding problems I had with some of my European species: Protaetia (potosia) cuprea, Protaetia (potosia) affinis and Cetonia aurata. Three different problems for three different species. Feel free to help me find out what exactly the problem is and how to solve it.
First some may think that these palearctic species come easy in breeding. My breeding experience so far has learned me that this surely isn't the case. Ofcourse the named potosia species aren't the most difficult species, but they aren't comparable in difficulty to the most common starter beetles. They have their points of attention, and in some cases things just don't turn out as aspected. Cetonia aurata on the other hand is a super easy species, but i noticed something interesting in their egg-laying behaviour. The three scenario's:
Protaetia (Potosia) cuprea cuprea: A fresh generation that just won't lay, nor age
I received a whole bunch of protaetia cuprea cuprea from Padua, Italy some years ago. The first generation (wild beetles) did really well and produced me some hundreds of larvae. I kept a nice bunch myself and sold some and gave away the rest.
The beetles were set in diapause in winter (not controlled, just put them up in a cool attic). In spring they started pupating in quite good synchronisation. Although I ended up with many adult beetles while some were still pupa, and some still L3. I made a big breeding box with leaf material and rotten wood, the usual basic recipe back then. I put the remaining pupal cells and L3 in the box too, so they could emerge naturally. During spring and summer the beetles were very active, buzzing about. They had daily sunlight and were fed solely on jelly. When I checked the breeding box in september there wasn't a single larvae or egg to be found! God dammn!
First of all I can wonder how this happened, and see only four possible explanations:
The beetles were set in diapause in winter (not controlled, just put them up in a cool attic). In spring they started pupating in quite good synchronisation. Although I ended up with many adult beetles while some were still pupa, and some still L3. I made a big breeding box with leaf material and rotten wood, the usual basic recipe back then. I put the remaining pupal cells and L3 in the box too, so they could emerge naturally. During spring and summer the beetles were very active, buzzing about. They had daily sunlight and were fed solely on jelly. When I checked the breeding box in september there wasn't a single larvae or egg to be found! God dammn!
First of all I can wonder how this happened, and see only four possible explanations:
1) The smell of late larvae and pupae in the soil inclined the beetles to lay eggs (?)
2) A bad sex ratio in beetles, allthough I have over 15 beetles being active (?). Or do they refuse to mate with siblings naturally (?). Potosia cuprea are also notoriously difficult to sex as adults.
2) A bad sex ratio in beetles, allthough I have over 15 beetles being active (?). Or do they refuse to mate with siblings naturally (?). Potosia cuprea are also notoriously difficult to sex as adults.
3) Sub-optimal diapause: not long enough or too long (?), not cold enough (?). Sadly at the time I didn't control my
diapause very much, nor did I take notes on it.
4) Sub-optimal nutrition due to only being fed jelly (?)
Any other suggestions by readers? Any feedback?
In autumn the beetles dug down in the substrate, preparing for another winter. I dug them up, put them in a smaller, more controlable box and set them up in the attic again from end of september to end of februari. After putting them up in a rather cool room temperature they got active again, and were found on top of the substrate trying to get to the light.
I gave them a luxury breeding box with new substrate made up out of white rotten wood, sphagnum peat, crushed kinshi blocks and some small amounts of bio pesticide-free potting soil to make the soil more "diggable" for the beetles and control moisture better.
The beetles now are again enjoying the light and (fresh) food, have had extra pollen for protein, and are being sprayed with water every other day, which they seem to like a lot. They are still full of energy, but I havn't seen a single mating yet. I really wonder if they will get to reproduction soon or not.
I gave them a luxury breeding box with new substrate made up out of white rotten wood, sphagnum peat, crushed kinshi blocks and some small amounts of bio pesticide-free potting soil to make the soil more "diggable" for the beetles and control moisture better.
The beetles now are again enjoying the light and (fresh) food, have had extra pollen for protein, and are being sprayed with water every other day, which they seem to like a lot. They are still full of energy, but I havn't seen a single mating yet. I really wonder if they will get to reproduction soon or not.
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| Active again and feeding in the beginning of march |
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| Part of the group before diapause end of september |
Protaetia (Potosia) Affinis: Too traumatised to lay?
Potosia affinis, a species I deeply love for it's variations and body-composition has also been refusing to lay eggs.
I received also wild beetles from this species some years ago. It was a big breeding group, of about 10 pairs. They reproduced without issue and gave me several hundreds of larvae. Same story as with cuprea: sold/gave away the mostpart and kept a big group myself. Sadly a Mecynorhina polyphemus larva that accidently got into the wrong tub (ofcourse by my own mistake). After some weeks only one single fat and happy Mecynorhina larva remained, and zero of Potosia affinis. Needless to say I felt like a joke :)
I received also wild beetles from this species some years ago. It was a big breeding group, of about 10 pairs. They reproduced without issue and gave me several hundreds of larvae. Same story as with cuprea: sold/gave away the mostpart and kept a big group myself. Sadly a Mecynorhina polyphemus larva that accidently got into the wrong tub (ofcourse by my own mistake). After some weeks only one single fat and happy Mecynorhina larva remained, and zero of Potosia affinis. Needless to say I felt like a joke :)
A friend helped me out because I was really deseperate to breed and select this species again. He had some P. affinis that had layed some eggs already. He send me these. I prepared a breeding box with flakesoil, peat and white rotten wood. I fed the beetles further with jelly and banana.
After checking this box too, there were no eggs nor larvae to be found.
The beetles themselves were never really active, moved rather slow and seldom attempted to fly, nor did they attempt to mate.
Once again a sad experience with this species. I question myself why they didn't breed. The substrate forms no problems with the other species I breed, humidity etc were the standard that I use for almost all species. Was it the turbulent shipment from Czech Republic to Belgium that might have caused this? Any other reason? I have no clue.
After checking this box too, there were no eggs nor larvae to be found.
The beetles themselves were never really active, moved rather slow and seldom attempted to fly, nor did they attempt to mate.
Once again a sad experience with this species. I question myself why they didn't breed. The substrate forms no problems with the other species I breed, humidity etc were the standard that I use for almost all species. Was it the turbulent shipment from Czech Republic to Belgium that might have caused this? Any other reason? I have no clue.
As summer got to an end ,the beetles were still slow but alive. I put them into diapause. Now in early march as the weather starts to get warmer, the beetles got active again. I put them together in a new breeding box now. They feed well and walk around slowly, but still, no mating to be seen.
Now I have my fingers crossed again, let's hope they lay a handful of eggs.
Cetonia aurata aurata: They don't want the good stuff
Not really a breeding problem, as Cetonia aurata is about the easiest palearctic species to be found, but some friends and I all got to same conclusion after trying to breed the species in some different ways.
The first time I bred this species I was still very novice. I received some wild beetles, and made them substrate out of leafs and wood. Just for the experiment I also added 1/3 of compost which we make at home to fertilise the vegetable garden. Cetonia aurata seemed to really like the substrate, and they produced over 200 larvae from 3 females. A very good reproductive rate indeed.
A year later I had already produced my first amounts of flake soil. The second generation of C. aurata thus got flakesoil instead of the usual substrate. After the adults passed, it was time to control the boxes. This time a group of 4 females (in a bigger tub than before) only produced about 60 larvae. After communicating with some other breeders I heard about the same results. This species doesn't seem to like high grade substrate. A french and italian breeder also reported that the species is often found in compost heaps and other accumulations of rotting plant material.
Conclusion: don't waste you flake on them, they like more low-grade substrate far more!
I'm watching the comment-section, my mailbox and social media to hear on your experiences with egg-laying problems in Cetoniidae, and perhaps on how you managed to solve them.
Should you have advice on how I can induce these species to lay eggs or know any reason why they don't do it at the moment, feel free to share your experiences :)
Regards from Belgium,
Domien
Comments
when breeding as a young boy, not so much with Protaetia affinis and Protaetia aeruginosa and literally none with cuprea cuprea. I bought a lot of larvae of Protaetia speciosa jousselini some years ago, after having seen the habitat of the latter in a trip to eastern Turkey and of Protaetia speciosa speciosa in southern Armenia, and made up my mind which circumstances have to be met, in order to give them good breeding conditions. I have the feeling that there is something with breeding the Genus Protaetia, that has yet to be understood. I am also curious if others find certain ways to improve breeding, because I am absolutely sure, there is a good recipe out there that only needs to be discovered.
For me, I had quite a good rate of upbringing beetle from larvae I think, but then failed mysteriously breeding them. I think it is very important to have the larvae grow in big containers, firstly because I think they are near to never cannibalistic, but also because they need a biologically stable substrate in my opinion, one that has a constant moisture(not so high), that doesn't have to be changed during one circle (ideally). Basically something like the cavity of an old tree, where this beetle breeds. That's my opinion. I used substrate which I collected from hollow trees, mixed with some dark flake soil that was already used a little by larvae before. I found it very, very helpful to put a top layer of dead oak leafs on top, cut into small pieces (but not mixed with the substrate) I helps keep the top layer from drying out and larvae also seem to like it.
I put them in the basement in winter, where they would have a few months of cold "weather", they tolerate it with no problem. After the second winter as I recall it, they emerged from their pupal cells and almost all of them seemed healthy and active. I had them a 60L terrarium, with a substrate-depth of firstly 20, then nearly 30 cm, next to the window and with artificial light also. White rotten wood was also put in there. After some months, they became so active, I saw them copulate, eat beetle jelly and other fruits and flying in the terrarium almost every day. They lived for a very, very long time, most of them came close to a year, which I found very cool. But to bring this story to an end, I never found eggs or larvae, which was very disappointing. Some tropical beetles in same conditions layed so many eggs like I've never seen before, but nope not speciosa.
I have very little time for breeding experiments right now due to job, but I know that I am not finished with Protatia yet, i will continue some day. That's my experience for now. Curious what others find out!
Best regards!
Indeed these species seem to have a difficult side to them. I neither know people who have reared protaetia cuprea for multiple subsequent generations. In p. cuprea is suppose this also has to do with the substrate.
Species like C. speciosa, C. speciossissima,... pose less of a problem and will lay in any high grade material if they had enough cool temperatures in winter. For P cuprea I think it goes beyond diapause. Many (often older) books state the larvae an be found in ants nests. Perhaps they need to smell something alike? I don't know really, just guessing!
Stability of substrate is im^portant for all saproxylic beetles. The most succesful Dynastes breeder of Europe in my opinion, a dutch guy who has been breeding for a long time, never changes his substrate, only adds more as the substrate get eaten. An interesting strategy, because indeed, tree hollows and other accumulations of detritus are very stable when it comes to temperature, humidtity etc.
Happy to meet another enthousiast for the protaetia genus! Never let work become an excuse to breed beetles :) I work a lot but still take my time for it. Sometimes a bit stressy but worth the effort!