Egg The common cockchafer begins as an egg, usually laid in the soil. Eggs are small, oval, and whitish, transitioning to a darker shade before hatching. At this stage, common cockchafer are immobile and are developing the basic structures for the next stage.
Larva Upon hatching, larvae resemble small, white grubs with a C-shaped body. As larvae, common cockchafer have a strong appetite, feeding voraciously, and they molt several times, growing larger after each molt. They lack wings and resemble neither parent.
Pupal In the pupal stage, common cockchafer transform inside a pupal case. Color changes from white to brown, indicating development. The size increases slightly, and the shape becomes more similar to the adult, with wing pads and leg outlines observable.
Adult The adult common cockchafer emerges with distinct hardened elytra and functional wings underneath. The body is robust, the color is typically brown or black, and the size is significantly larger than earlier stages. Adults are sexually mature, focusing on reproduction and dispersal.