Written by Time to write about a flower beetle again, it has been many posts on stag beetles recently, but I still have some Cetonidae on the side. One of these species is Protaetia cretica, a Cetonid from the Island of Crete in Greece. These are relatively easy, but have some special requirements that they share with most other species from the Palearctic regions, and I think it makes sense to write this down.
Protaetia cretica
I got a group of four pairs last year September, which were somewhat active, and feeding, but no interest in mating. This normally means two things, either they are missing some hibernation period, or they are just not active yet. In the case of Protaetia cretica it was the first. I decided to provide them with a winter period. For that purpose, I filled a container with slightly humid substrate to the top, put in the beetles, and then stored it in my refrigerator, where the temperatures fluctuate only slightly, from 1-5 degree Celsius. After they had been placed in the fridge, all I needed to do was to check on them every other month, to see if the substrate was still humid enough (refrigerators are also very efficient in drying things). Interestingly they would move around in the substrate, albeit super slowly. So I wasn’t entirely sure if I was doing the right thing. That said, they seemed fit overall, and in March I decided to set them up for breeding, just in time for spring.
I prepared a box with wood-leaf compost, and placed it on the windowsill of a South facing window. When summer progressed, I moved them to an East Facing window, to assure they are not cooked. Why this works, is that the window frame blocked the box portion that had the substrate, so was not affected by the heat. Why sunlight? Well, this is an old/new epiphany I had. I have a few years of being quite unsuccessful with Cetonidae, and was always wondering why. With the move to a new apartment and the availability of windows, I tried to place breeding containers on the windowsills, and all of a sudden, lots of activity and eggs, eggs, eggs. I think that for the day-active species sunlight is very important and that my other light sources were never strong enough or did not provide light of the right composition, to actually enhance my beetles to lay many eggs.
Probably no news to the many Cetonidae breeders in this world, but a mistake I had made, and another piece in the puzzle. I offered banana, apple and beetle jelly as a food source, and while they preferred banana over everything else, they did not turn down the other options. That said, fermenting banana seems to provide a lot of good nutrients to the beetles, and I would suggest it’s use over beetle jelly, if I was forced to decide.
I moved the beetles on a cool day, so the shock of temperature was not too great, and had the window open during the day. They were easy though, and the next day already eating and mating. The daylight and good food did their part as well, and I ended up with many eggs.
Protaetia cretica female eating a larva
With regards to development, Protaetia cretica is super fast. Eggs were laid from March onwards, and I do now have the next generation in cocoon, and ready to go into the refrigerator again. Total cycle is still a year, but 6 months are hibernation. With regards to larval feeding, keep them communal and feed them with leaf compost or flake soil. Protaetia creatica are easy and undemanding that way.
Protaetia cretica
The hibernation is necessary in my opinion, maybe not for the first generation, but there have many issues with continuous breeding of Protaetia and others from climate regions. Lesser and lesser eggs and more and more problems. So, if you are keeping these, or any other that are considered hot now, like Protaetia speciosa cyanochlora, reserve them a spot in your refrigerator. One last word, I have also hibernated larvae of another species, Protaetia marginicollis, which worked fine. They pupated after it warmed up again, and then started laying eggs now. I am still unsure which is the better process – follow the normal pattern of seasons, or keep them cool when they have just become beetles. Let me know your thoughts.
Protaetia cretica
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