Lucanidae

There are about 1200 species of stag beetle (so called because the horns are meant to resemble the antlers of stags). The horns are used in fights with males over mating and food. Interestingly , the female jaws though much smaller are more powerful than the males

The larvae feed on rotting wood for several years (3-7), the females can be identified by fat ,cream coloured ovaries about 2/3 of the way along the back.

The size of the males jaws depend on genetic and nutritional factors during development.