Basic beetle life cycles for stag, rhino and flower beetles.
Most beetles have a hugely fascinating life cycle. Some species have a very short life cycle and reproduce fast others have a very long grub stage. The basic principles are that the beetles lay eggs generally in the substrate or within rotting logs. These eggs hatch out and the grubs develop. Grubs go through 3 main development stages named L1, L2 and L3. Grubs then form a cocoon using the substrate and any other materials around them to create a protective bubble to pupate in. This can sometimes be found attached to logs, sides of enclosures or onto other cocoons. It is important not to open these or move them around when the grub is developing.
Rough Grub Sexing
Figuring out the sex of your grub before they pupate isn't the easiest job in the world. Firstly grubs generally don't like to participate in the fondling that is required, they can bite, they are normally covered in soil and finally you will need a to wait until the grub is at L3 stage before this is possible.
To sex a grub, you will need to hold the grub so that is underside is showing. Be careful as they will try and bite you at this stage.
Look for a single dark black dot in the centre of the lower segments. This can often be mistaken for hair, however once you trains your eyes to its location it will be easier to find.
A black dot means that your grub is male.