Two-spotted Lady Beetle

• It is one of the most colour-polymorphic species known among beetles, to the point that identifying it by eye is not always straightforward.
• Its elytra carry glands that secrete a waxy substance by which individuals recognise one another and trigger courtship.
• The larvae are cannibals: when aphids run short they eat the eggs and larvae of their own species.
• Its coloration is extraordinarily variable: there are red forms with two black spots and black forms with red spots, and both live side by side in the same population. The proportion shifts with pollution and climate, a case comparable to the industrial melanism of the peppered moth.
• It carries bacteria that kill its males. Several species of maternally inherited bacteria, among them Wolbachia, Rickettsia and Spiroplasma, kill male embryos inside the egg; the females eat their dead brothers and start life with an advantage.
• In some populations those bacteria go so far as to skew the sex ratio, leaving populations with vastly more females than males.
• It is bred and sold as a biological control for aphids in greenhouses and gardens.
• It is being pushed out across much of Europe by the harlequin ladybird, Harmonia axyridis, which preys on it and displaces it.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat & environment

Trees and shrubs in green spaces, gardens, parks and farmland, wherever there are aphid colonies

Size at birth

Rugby-ball-shaped eggs, orange-yellow, 1 to 1.5 mm long

Sexual maturity

The full cycle from egg to adult takes about 20 days at 20 °C

Litter / clutch size

The female lays her eggs on the underside of leaves, near aphid colonies. The cycle passes through four larval stages before pupation

Sources consulted: Asturnatura; controlbiologico.info; Wikipedia (Adalia bipunctata); Agrológica (ficha de plaga); De vueltas por el mundo

Best time: From spring to autumn, on the trees and shrubs of gardens, parks and crops