Adalia bipunctata

Adalia bipunctata, the two-spot ladybird, two-spotted ladybug or two-spotted lady beetle, is a carnivorous beetle of the family Coccinellidae that is found throughout the holarctic region. It is very common in western and central Europe. It is also native to North America but it has heavily declined in many states and provinces. It is commonly introduced and imported as a biological control agent.

Taxonomy

The two-spotted ladybird was one of the many species originally described by Carl Linnaeus in his 1758 10th edition of Systema Naturae; its original name was Coccinella bipunctata. Its specific name is from the Latin bi- "two", and punctata "spotted".

Varietas

Adalia bipunctata var. annulata (Linnaeus, 1767)
Adalia bipunctata var. bipunctata (Linnaeus, 1758)
Adalia bipunctata var. fasciatopunctata (Faldermann, 1835)
Adalia bipunctata var. quadrimaculata (Scopoli, 1763)
Adalia bipunctata var. revelierei Mulsant, 1866
Adalia bipunctata var. turanica Luis, 1947

Description

Adalia bipunctata is a small Coccinellid that can feature any one of a large selection of red and black forms. Some forms are similar to Mulsantina picta, but the two white spots on the head of Adalia (in contrast with a large white region or more than two spots) readily separate it. Additionally, Adalia is entirely black on the ventral surface with black legs, which helps rule out any other options.

The two-spotted ladybird is highly variable in many parts of its native range. The most familiar form, form bipunctata (forma typica) with two black spots on a red base, is common throughout. A melanistic form that is black with four or six red spots is uncommon, but not rare, while the truly melanistic form is exceedingly rare. In North America the species shows the most variation, with several forms that do not occur elsewhere including a spotless form, a four-banded form, a nine to twelve spotted form, and a "cross-hatched" form. In addition, there are intermediate forms such as form annulata, but they occur rarely.

Prey

Two-spotted lady beetles feed on aphids and other small insects. However, the sterile soldiers within colonies of aphids such as the gall-forming Pemphigus spyrothecae, can attempt to protect the aphid colony by fighting this species.

thumb|left|Adult beetle eating an aphid

Life cycle

The two-spotted lady beetle's life cycle starts with eggs that are usually laid in clutches. Rickettsia, and Spiroplasma) which are present in between 0 and 20% of females, depending on locality.

Parasitism

The two-spot ladybird also carries a sexually transmitted infection in Central and Eastern Europe. This is an ectoparasitic mite Coccipolipus hippodamiae that transfers between male and female (and female and male) during copulation. The infection sterilizes female two-spot ladybirds, and at some points of the year, up to 90% of adult two-spots become infected.

As biological control agent

A. bipunctata is used as a localised biological control agent against aphids in, for example, greenhouses. The two-spotted lady beetle was introduced into Australia specifically as a biological control agent.

Gallery

2 spot ladybird (Adalia bipunctata) (7392018428).jpg|A. bipunctata var. annulata

Two-spotted lady beetle (11036).jpg|A. bipunctata var. bipunctata

Jacobson coccinella fasciatopunctata.png|A. bipunctata var. fasciatopunctata

Adalia bipunctata 122756835.jpg|A. bipunctata var. quadrimaculata

Adalia bipunctata v sexpustulata (14438448853).jpg|A. bipunctata var. sexpustulata

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