Ladybugs are known as a symbol for biological crop protection:
- One larva eats up to 150 aphids each day.
- The adult beetles are predators as well and eat up to 50 aphids daily.
Adult Adalia bipunctata can occur in two different appearances:
- red beetles with two black spots
- black beetles with two red spots.
Ladybirds lay their oval, yellow eggs as packages near the aphids. The egg laying period takes 2-3 weeks. After about one week, the larvae hatch and immerdiately start to search for aphids. As the larvae are blind, they find the aphids via tactile sense. Shortly before each moulting, the larvae cling to the underground and remain immobile for a period of several hours or even a whole day.
Before pupation, the larva moults three times within two weeks. After 6-8 days, the adult beetle breaks the pupa cyst. In the beginning, the hindwings are yellow and spotless, and the beetles look for a save place to dry and harden them. After several hours, the black spots appear.
At this stage, only 20% of the insects survive in open nature.
For overwintering, the beetles seek hiding places such as under bark or in recesses of facades.
T he beneficials are delivered in the larval stage.