Rearing Blaps gigas

Matt

Matt

Pupa
Does anyone have any experience of rearing Blaps, or more specifically Blaps gigas. I met a nice lady at a recent bug show who brought a couple of Blaps gigas back to the UK from Morocco. Her beetles are laying and the eggs are hatching, the larvae grow happily but then fail to pupate and die.

I'm thinking the problem is something to do with their pupation requirements, a bit like Giant Mealworms never really pupating sucessfully if they are kept with other larvae, so I will be trying various options such as providing a big lump of dead wood or keeping a few larvae in solitary to see what happens.

Meanwhile, any advice. I notice there was something on Blaps published in Invertebrates magazine a while back, does anyone have a copy of the article please.

Thanks

Matt

 
Orin says that all darklings (even North American species) except T. molitor and grain pests need to either be isolated in cups or given an environment with six inches or more of substrate and lots of room for the larvae to pupate. It is also mentioned that in the non-isolated environment the larvae have to be around the same age, since pupae are happily cannibalized.

Did the lady have the larvae die before or after they became pupae? If the latter is true, then B. gigas has special requirements for keeping pupae alive which may have nothing to do with isolation.

 
The larvae have never managed to get to the pupal stage. Her description of events is "the larvae hatch, they get big, then then they reach a maximum size and then just die", which suggests to me that an appropriate pupation site is lacking.

 
I suggest you put each larva in its own container with substrate so it can dig a cell whenever it needs to.

Even Z. morio larvae will make pupal cells from compost if they are alone.

 
A quick update. I separated out 10 or so of the larger larvae and potted them individually in various sized plastic lidded tubs / deli containers. After a week or so most of them appeared to have made a cell and were laying on their backs. Finally the other day I saw the first pupa in one of the cells, so it looks like they have a pre-pupa time of 4-5 weeks.

Fingers crossed I get a few more to pupate and then get adults.

 
Pupation and pupation sites seems to be the key for this species. I lost the first couple of pupa which built cells in the substrate to mould, which suggests they need a fairly dry pupation site. Removed the next few from their cells soon after pupation and have kept them in a bare plastic tub. Got the first adult out about a week ago which i think is a male. 1 more emerged yesterday and one more is about to emerge immanently, both of which I think are females.

DSCN5653_zpsgg5l0yxb.jpg


Blaps gigas shortly after emergence - the elytra are still very soft and uncoloured.

 
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