Wikispecies has information related to: Adalia bipunctata

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Adalia bipunctata, commonly known as the two-spot ladybird, two-spotted ladybug or two-spotted lady beetle, is a carnivorous^[1] beetle of the family Coccinellidae that is found throughout the holarctic region. It is very common in western and central Europe and North America. It is used as a biological control agent.

Taxonomy

The two-spotted ladybird was one of the many species originally described by Linnaeus in his 18th century work, Systema Naturae, its original name was Coccinella bipunctata.^[2] Its specific name from the Latin bi- "two", and punctata "spotted".^[3]

Phenotypic variations

The most familiar form of the two-spot ladybird beetle is the red one with the two black spots. However, there also exists a black form with red spots on it. In addition, there are intermediate forms, but they occur only rarely in nature.^[4]

Prey

Two-spotted lady beetles feed on aphids and other small insects.^[1][4][5]

Life cycle

Life cycle

The two-spotted lady beetle's life cycle starts with eggs that are usually laid in clutches.^[1][5] The larvae hatches from the egg by biting a hole in it. The larvae look very different from the adults: they have elongated, grey, soft bodies with six legs but no wings. They are cannibalistic. Larvae go through four larval stages: by eating they grow and at some point they shed their old skin and appear in a new one in which they can grow more. The last larval stage is approximately the size of an adult beetle. Once it has eaten enough, the larvae attach themselves to a substrate and moult into a pupa. Inside the pupa, the adult develops. Finally the adult ecloses from the pupa.

Sex ratio anomalies

Spotted lady beetles mating

Symbiosis

In some populations, the majority of the beetles are female. In these populations, 80-90% of the offspring of a female are female. The cause of this anomaly is the presence of symbiotic bacteria living within the gametic cells of the female lady beetles. The bacterium is too large to live in the male gametes (sperm), so the bacterium can be transmitted to the next generation only through female gametes. When it ends up in a male, it will die when the male dies. Therefore, it kills most of the male embryos in the newly laid eggs. These dead embryos then serve as food for their sisters when they emerge from their eggs. This trait is associated with a variety of different bacteria (Wolbachia,^[6] Rickettsia,^[7] Spiroplasma^[8]), which are present in between 0 and 20% of females, depending on locality.^{[citation needed]}

Parasitism

The two spot ladybird also carries a sexually transmitted infection in Central and Eastern Europe. The infection is an ectoparasitic mite Coccipolipus hippodamiae that transfers between male and female (and female and male) during copulation.^[9] The infection sterilizes female two spot ladybirds, and at some points of the year, up to 90% of adult 2-spots become infected.^{[10][citation needed]}

As biological control agent

A. bipunctata is used as a localised biological control agent against aphids in, for example, greenhouses.^{[citation needed]}. The Two-spotted lady beetle was introduced into Australia specifically as a biological control agent.^[11]

References