Chrysina beyeri (video)

[Goliathus]

More of my Chrysina beyeri (Purple-legged Jewel Scarab) are starting to emerge.  Based on their size, I think that most if not all of the ones shown in this video are males, but I'm really not certain.  I expect that larger specimens will be emerging a bit later (in another 4 to 6 weeks or so).  These particular ones were reared at some density in a communal, 10 gal. tank.  I suspect that those I reared individually in 16 oz. containers will be larger.

 

[aspenentomology]

Wow, they're absolutely gorgeous... The name jewel scarab is very well deserved, although I would consider these to be even better looking than actual jewels lol.

 

[MasterOogway]

I'm interested to know the size difference in singly vs communally raised grubs.  Please let us know once the single-raised grubs start to emerge!

 

[Goliathus]

Wow, they're absolutely gorgeous... The name jewel scarab is very well deserved, although I would consider these to be even better looking than actual jewels lol.

I totally agree!

I'm interested to know the size difference in singly vs communally raised grubs.  Please let us know once the single-raised grubs start to emerge!

I just had my first single-raised beyeri adult emerge last night, and indeed, it was noticeably larger.  My feeling is that the size difference is not so much related to the larvae being reared in a group, but is more just a result of crowding.  So, if you keep perhaps 25 C. gloriosa (or perhaps 20 beyeri) larvae together in something the size of a 10 gal. tank filled to 50% to 75% capacity and make sure that they have good substrate conditions, they would probably grow just as large as larvae that were kept singly.  What you want to be careful to avoid when rearing in a group, is to not let too much of the substrate be converted to frass, as this will ultimately result in smaller growth.  So, for optimal results, best to keep the density of larvae within reasonable limits, so that they aren't really competing with each other for space and food resources.

 

[arizonablue]

Wow, those are beautiful! Thank you for sharing the video!

 

[MasterOogway]

Good to know. I've got a 17L bin ready for some grubs, but have plentiful 32oz deli cups available as well. I may give both a try and see how it goes. As always, thanks for the information on these guys! 

 

[davehuth]

What you want to be careful to avoid when rearing in a group, is to not let too much of the substrate be converted to frass, as this will ultimately result in smaller growth. 

This caught my attention. I presume this would be the same for other Scarabaeidae? My second generation Gymnetis thula are popping out smaller than the founding adults. They're in about an 8-ish gallon enclosure, but I bet I have more than 50 larvae in there. I change it all out fresh twice a year. I think the substrate is fairly high value (all rotting wood and hardwood leaves, no filler like coconut fiber). And I supplement with surface treats like fruit and squash that are actively dragged under. But maybe they're still just motoring through it all too quickly? I guess I may have to step up my maintenance game?

 

[MasterOogway]

This caught my attention. I presume this would be the same for other Scarabaeidae? My second generation Gymnetis thula are popping out smaller than the founding adults. They're in about an 8-ish gallon enclosure, but I bet I have more than 50 larvae in there. I change it all out fresh twice a year. I think the substrate is fairly high value (all rotting wood and hardwood leaves, no filler like coconut fiber). And I supplement with surface treats like fruit and squash that are actively dragged under. But maybe they're still just motoring through it all too quickly? I guess I may have to step up my maintenance game?

I'm replacing/adding oak leaves (primarily) to my Gymnetis bins at least once a month at this point, with probably anywhere between 25-50 grubs in some 17L bins.  They don't eat as much as my Pachnodas, but are still hungry little monsters.  

 

[Goliathus]

This caught my attention. I presume this would be the same for other Scarabaeidae?

Yes - if larvae are kept in groups, I'm always careful to keep the number below the limit at which competition will occur.  That way, the larvae will reach their full potential size.  In the case of Dynastes tityus for example, I keep no more than 8 larvae per 10 gal. tank (filled to 75% capacity with substrate) once they reach L3.

My second generation Gymnetis thula are popping out smaller than the founding adults. They're in about an 8-ish gallon enclosure, but I bet I have more than 50 larvae in there. I change it all out fresh twice a year. I think the substrate is fairly high value (all rotting wood and hardwood leaves, no filler like coconut fiber). And I supplement with surface treats like fruit and squash that are actively dragged under. But maybe they're still just motoring through it all too quickly? I guess I may have to step up my maintenance game?

50 thula larvae in an 8 gal. container is fine - it's the frequency of the addition / change of substrate that matters.  I typically keep 50 thula larvae in a 16 quart plastic storage box, and so long as I make sure that the substrate supply is kept up, they all reach normal size.  I screen out all of the frass at least once a month, and mix in whatever amount of new substrate is needed to bring the depth back up to what it was originally.  50 thula larvae can convert quite a bit of substrate into frass over the course of a month.  And yes, it's definitely helpful to offer the larvae of this species supplements such as apple if rearing them at some density, just to make sure they get what they need.