Reproduction and development of insects
Insects have separate sexes. Males are often smaller than females, with strongly developed antennae and a good sense of smell. The female has a pair of ovaries and the male a pair of testes in the abdominal cavity. The rose chafer lays fertilised eggs in rotting wood; a whitish, thick, arc-curved grub hatches, feeds on humus, moults several times and becomes a pupa. The pupa is motionless and does not feed; complex changes occur and an adult beetle emerges. This development is complete metamorphosis (egg – larva (grub) – pupa – adult); it occurs in beetles, butterflies, flies, bees and ants. In incomplete metamorphosis there is no pupal stage: the larva that hatches from the egg resembles the adult, only small and wingless, and grows by moulting several times (cockroach, locust, dragonfly, bug).
Card game: put “egg, larva (grub), pupa, adult” in the right order, then compare diagrams for a beetle and a locust. Safety: collect insects only with adults and do not harm them.