Protaetia (Potosia) fieberi: charasteristics and breeding
The Protaetia genus contains over 300 species. This genus is well established in Eurasia and the old world tropics. About some species that occur in Europe we know a whole lot thanks to the work of both early and modern entomologist. Since a collecting trip last year I added some new species to the list, one of which is Protaetia (Potosia) fieberi (Kraatz, 1880). Here a detailed macro of this species, by Thomas Moeyaert , photo used with permission ofcourse.
Like many of these widely distributed species it comes in many different forms and a couple of subspecies. The typical forms is shown also on the picture above. A dull green-bronze colour on the elytrae. There or even some hyperchromatic forms, which display a high black or red tone. Colour variations are estimated to occur only 1 per 1000 specimens; 0.1%.
The life history of this beetle remains little understood. Larvae and frass of this species have been found in tree hollows made by different species of woodpeckers and small mammals.
Larvae of Potosia fieberi have never been found living in the same hollow with other species of Cetoniinae. The explanation for this is unknown.
Potosia fieberi seems also to avoid altitudes higher than 1800m. It's number are signicantly lower on altitudes higher than 1000m above sealevel, even if the associated flora is present.
The species is a strict forest species depending, like many sacrophagous beetles, on old trees.
The beetles are diurnal. The period of activity differs based on location. In more warm area's like France, Italy and Greece these beetles get active in late may/june. In Ukraine and Russia these beetles get active later, having their peak in august. Beetles can remain to be found in september. They probably die of cold in october.
They fly mostly during midday on sunny days, from aprox. 11h to 14h. They are not specific when it comes to prefered food source. The species is mainly found on flows of tree sap. In the wild they also visit flowers of different kinds of trees that flower in their period of activity. Given they get active in june to july, this trees are mostly chestnut trees, roses and many others.
They are attracted to typical window-traps with yeast, rotting fruit, beer or wine.
Substrate:
These beetles have been bred on leaf-substrate, but have proven to not lay eggs abundantly in it. Better results are reported in substrate consisting of leafs with a big proportion of finely mulched white rotten wood.
From my own experience: I reared these beetles on a mix of approximately 30% sphagnum peat, 30%flake-soil and 40% white rotten wood (both mulched and big chunks). I had 6 wild beetles in the substrate (sex ratio not determined), resulting in over 110 larvae, of which I sold some at a recent fair.
The remaing larvae are being kept in the same substrate as was used for egg-laying.
Life cycle:
Both in the wild as in captivity these beetles need a diapause.
Larvae develop from july to october. When temperatures drops during fall and winter, the larvae go into diapause. When temperatures start rising in march, they get active again and develop further. Pupation starts around half april to may. Pupation takes about 26 days. The beetles get active in june.
Egg laying is reported to take only 2 months. In my personal breeding I still found eggs in late september, at a time when my Potosia fieberi where already 4 months active.
In the wild these beetles, as described earlier, probably die in october. From my personal collection I have a very different experience with this. From the six specimens I caught in Czech Republic in late may, one survived until october, another I found dead just 3 weeks ago, in early december. This beetles had lived almost 7 months!! Ofcourse this beetle had the best care it could have possibly found :)
The results and my succes from my own breedings will be reported later on. The larvae are currently in diapause. According to discussion on fora and personal communication, this species is not easy to get to imago stage. But the big difference is that many used leaf-substrate, which has the risk of being full of diseases.
We will have to see wether the substrate I used might offer better results. Also we can hope that with the 60+ larvae I have in breeding, hopefully I might hit the odds and hit a rare variation.
I will report on my results in a later post.
Fingers crossed.
--------------------------------------------------------------------------------------------------------------------------
Update June 2019: The breeding so far did go perfect. I send some larvae to two other entomologist and remained with 23 larvae. They were all together in a 10L box. My approach was to give them plenty of flakesoil for their entire development. I didn't dig up all the larvae for controlling. Just checked once every now and then to see if there were no troubles in the substrate, look for a couple of larvae to check their health. All went well. After the diapause they started feeding again and soon turned into bulky L3 larvae. I kept adding flakesoil as the the substrate got consumed, but didn't remove anything.
The beetles went into an almost perfectly synchronised pupation, most against the sides of the box, allowing perfect monitoring. See picture below.
After about a month after I noticed the pupation, the beetles were enclosing in synchronisation. From a total of 23 cells I had 21 beetles. Two larvae deceased in their pupal-cell without having entered pupation. The remaining beetles were active from the beginning. The elytrae were smooth without deformities, and the beetles themselves looked bigger than the wild beetles Petr Malec and me caught in Czech republic. I still have to do the measurements on size.
 |
| Protaetia (Potosia) fieberi, by Thomas Moeyaert |
Unlike many other European Cetoniinae, the specific life history of this beetle is little understood. Also the breeding of this beetle seems to be difficult according what I read online and from discussions with other enthousiasts of Palearctic Cetoniinae. The things that are known about this beetle are buried deep in the multilangual chaos that is European entomology.
I decided to dig down into this mess and make a synopsis. In this blogpost I will discuss the physical aspects of this species, their natural history and their breeding.
I decided to dig down into this mess and make a synopsis. In this blogpost I will discuss the physical aspects of this species, their natural history and their breeding.
Characteristics:
Potosia fieberi is a rather small Cetoniinae, measuring between 15-24mm.
It is heavily punctured across the pronotum, elytrea and and head. Halfway down the elytrae it has a depression, which has a diagonal upper edge. Due to this depression it looks a lot like Potosia cuprea. The difference is well explained in this picture:
It is heavily punctured across the pronotum, elytrea and and head. Halfway down the elytrae it has a depression, which has a diagonal upper edge. Due to this depression it looks a lot like Potosia cuprea. The difference is well explained in this picture:
 |
| Source: This forum , picture by Stephane Vassel. |
Potosia fieberi in general has very subtle markings, markings can also be completely absent.
The species can be divided into 3 subspecies, of which some have variations described. A short list of variations and subspecies:
- Protaetia (Potosia) fieberi ssp fieberi var. typica, Kraatz 1880:
The typical form occuring in most of western- and central-Europe.
As described ealier. Dull green-bronze elytrae with fine markings. Ventral side varies: Deep purple, red, green.
- Protaetia (Potosia) fieberi ssp fieberi, var. barilloti, Devecis, 1992:
I found little data on where this form can be found, only collections I could visit online show this subspecies present in central-france.
This variation is almost completely black. The elytrae have a reflective black shine, the pronotum doesn't relfect. The ventral side is black, legs are black.
- Protaetia (Potosia) fieberi ssp fieberi var. dumasi, Devecis, 1992:
I found little data on where this form can be found, only collections I could visit online show this subspecies present in central-france.
Published in the same article as the one before. Variation dumasi is highly red in the pronotum. The elytrae are either deeply green or red-purple. The ventral side is deeply green. Probably not determinable by people who have daltonism :).
- Protaetia (Potosia) fieberi ssp borysthenica, Medvedev,1964:
Occuring in Ukraine and Western russia
This subspecies is highly green and has a bright metallic reflection on the elytrae and pronotum. Markings on the elytrae very bright and white. The most reflective of all the subspecies and variations.
- Protaetia (Potosia) fieberi ssp boldyrevi, Jacobson, 1909:
Green metallic subspecies with plenty of white marking on the elytrae and on the ventral sides. It often displays white spots on the outer edges of the sternites. De ventral side is red, the legs are red.
- Protaetia (Potosia) fieberi ssp fabriciana, Reitter 1898:
Known from central-Europe and Greece. These specimen have bronze elytrae and pronotum, with a red ventral side. Markings ar often completely absent or are not expressed brightly white.
Sidenote: It seems to me that fieberi is a beetle which is often underrepresented in collections. Online information is hard to find, especially when it comes to distribution of the different forms and subspecies. Given the rarity of certain variations and the absence of variation descriptions within different subspecies, I think there is still promising work to do for taxonomists here. Finding and describing this subform would require trapping of thousands of P. fieberi in the hopes of catching that 0.1% chance. I think that this would especially be interesting in Eastern and Central-Europe, as well as in Russia and ex-soviet countries. In these territories there is abundance of P. fieberi ,but very little typology to match it.
The species can be divided into 3 subspecies, of which some have variations described. A short list of variations and subspecies:
- Protaetia (Potosia) fieberi ssp fieberi var. typica, Kraatz 1880:
The typical form occuring in most of western- and central-Europe.
As described ealier. Dull green-bronze elytrae with fine markings. Ventral side varies: Deep purple, red, green.
- Protaetia (Potosia) fieberi ssp fieberi, var. barilloti, Devecis, 1992:
I found little data on where this form can be found, only collections I could visit online show this subspecies present in central-france.
This variation is almost completely black. The elytrae have a reflective black shine, the pronotum doesn't relfect. The ventral side is black, legs are black.
- Protaetia (Potosia) fieberi ssp fieberi var. dumasi, Devecis, 1992:
I found little data on where this form can be found, only collections I could visit online show this subspecies present in central-france.
Published in the same article as the one before. Variation dumasi is highly red in the pronotum. The elytrae are either deeply green or red-purple. The ventral side is deeply green. Probably not determinable by people who have daltonism :).
- Protaetia (Potosia) fieberi ssp borysthenica, Medvedev,1964:
Occuring in Ukraine and Western russia
This subspecies is highly green and has a bright metallic reflection on the elytrae and pronotum. Markings on the elytrae very bright and white. The most reflective of all the subspecies and variations.
- Protaetia (Potosia) fieberi ssp boldyrevi, Jacobson, 1909:
Green metallic subspecies with plenty of white marking on the elytrae and on the ventral sides. It often displays white spots on the outer edges of the sternites. De ventral side is red, the legs are red.
- Protaetia (Potosia) fieberi ssp fabriciana, Reitter 1898:
Known from central-Europe and Greece. These specimen have bronze elytrae and pronotum, with a red ventral side. Markings ar often completely absent or are not expressed brightly white.
Sidenote: It seems to me that fieberi is a beetle which is often underrepresented in collections. Online information is hard to find, especially when it comes to distribution of the different forms and subspecies. Given the rarity of certain variations and the absence of variation descriptions within different subspecies, I think there is still promising work to do for taxonomists here. Finding and describing this subform would require trapping of thousands of P. fieberi in the hopes of catching that 0.1% chance. I think that this would especially be interesting in Eastern and Central-Europe, as well as in Russia and ex-soviet countries. In these territories there is abundance of P. fieberi ,but very little typology to match it.
Life history:
The life history of this beetle remains little understood. Larvae and frass of this species have been found in tree hollows made by different species of woodpeckers and small mammals.
The available information doesn't show a prefered wood type or tree species. They seem to inhabit both hard wood (Quercus sp., Tilia sp., Fagus sp.) as well as more fast growing wood types like willows and poplar (Salix sp, Populus sp.). This species is also associated with white accacia (Robinia pseudocacacia) in Russia and Ukraine.
Larvae of Potosia fieberi have never been found living in the same hollow with other species of Cetoniinae. The explanation for this is unknown.
Potosia fieberi seems also to avoid altitudes higher than 1800m. It's number are signicantly lower on altitudes higher than 1000m above sealevel, even if the associated flora is present.
The species is a strict forest species depending, like many sacrophagous beetles, on old trees.
The beetles are diurnal. The period of activity differs based on location. In more warm area's like France, Italy and Greece these beetles get active in late may/june. In Ukraine and Russia these beetles get active later, having their peak in august. Beetles can remain to be found in september. They probably die of cold in october.
They fly mostly during midday on sunny days, from aprox. 11h to 14h. They are not specific when it comes to prefered food source. The species is mainly found on flows of tree sap. In the wild they also visit flowers of different kinds of trees that flower in their period of activity. Given they get active in june to july, this trees are mostly chestnut trees, roses and many others.
They are attracted to typical window-traps with yeast, rotting fruit, beer or wine.
 |
| A wild P. fieberi feeding on elderflower by Cyril Lefevre |
Captive breeding:
Substrate:
These beetles have been bred on leaf-substrate, but have proven to not lay eggs abundantly in it. Better results are reported in substrate consisting of leafs with a big proportion of finely mulched white rotten wood.
From my own experience: I reared these beetles on a mix of approximately 30% sphagnum peat, 30%flake-soil and 40% white rotten wood (both mulched and big chunks). I had 6 wild beetles in the substrate (sex ratio not determined), resulting in over 110 larvae, of which I sold some at a recent fair.
The remaing larvae are being kept in the same substrate as was used for egg-laying.
Life cycle:
Both in the wild as in captivity these beetles need a diapause.
Larvae develop from july to october. When temperatures drops during fall and winter, the larvae go into diapause. When temperatures start rising in march, they get active again and develop further. Pupation starts around half april to may. Pupation takes about 26 days. The beetles get active in june.
Egg laying is reported to take only 2 months. In my personal breeding I still found eggs in late september, at a time when my Potosia fieberi where already 4 months active.
In the wild these beetles, as described earlier, probably die in october. From my personal collection I have a very different experience with this. From the six specimens I caught in Czech Republic in late may, one survived until october, another I found dead just 3 weeks ago, in early december. This beetles had lived almost 7 months!! Ofcourse this beetle had the best care it could have possibly found :)
The results and my succes from my own breedings will be reported later on. The larvae are currently in diapause. According to discussion on fora and personal communication, this species is not easy to get to imago stage. But the big difference is that many used leaf-substrate, which has the risk of being full of diseases.
We will have to see wether the substrate I used might offer better results. Also we can hope that with the 60+ larvae I have in breeding, hopefully I might hit the odds and hit a rare variation.
I will report on my results in a later post.
Fingers crossed.
--------------------------------------------------------------------------------------------------------------------------
 |
| Protaetia fieberi larvae |
The beetles went into an almost perfectly synchronised pupation, most against the sides of the box, allowing perfect monitoring. See picture below.
 |
| Protaetia fieberi pupae |
I prepared a big breeding box for the beetles to breed in. This will be the final step of this species: checking if they are fertile. If not I suppose the diapause wasn't sufficient.
Pictures of the new set up below. I keep this box outside in the shade of chestnut tree. The beetles can handle the cool spring nights and buzz around when the days get a bit warmer. I will leave the box unchecked for some months. If all goes well I will have some hundereds of larvae from this big breeding group.
From my previous stock I learned that this beetle can live very long. One of the beetles I collected in early june kept on livig until december. Not bad for a little cetonid.
From my previous stock I learned that this beetle can live very long. One of the beetles I collected in early june kept on livig until december. Not bad for a little cetonid.
 |
| Protaetia fieberi in breeding |
 |
| Munching |
 |
| Protaetia fieberi breeding box |
 |
| Protaetia fieberi ventral side |
Comments