Two-Spotted Lady Beetle

Fascinating facts about the Two-Spotted Lady Beetle

• In some populations, the majority of the beetles are female. In these populations, 80-90% of the offspring 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 bacteria (Wolbachia, Rickettsia, and Spiroplasma) which are present in between 0 and 20% of females, depending on locality. The skewed sex ratio gives sisters a food boost.
• Adult two-spotted lady beetles are 4-5mm long, and ovoid in shape. The head and thorax is black with yellow markings, while their elytra (wing covers) are orange with one black spot on each side. 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.
• The two-spotted lady beetle's life cycle starts with eggs that are usually laid in clutches. The larva hatches from the egg by biting a hole in it. They are cannibalistic. A larva goes through four larval stages: by eating, it grows, and at some point it sheds its old skin and appears in a new one in which it can grow more. The last larval stage is approximately the size of an adult beetle. Once it has eaten enough, the larva attaches itself to a substrate and moults into a pupa. Inside the pupa, the adult develops.
• 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 sterilises female two-spot ladybirds, and at some points of the year, up to 90% of adult two-spots become infected. Such high infection rates can dramatically reduce reproductive output, threatening local populations and highlighting how parasite pressure can shape ladybird community structure.
• 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. This species helps control populations of aphids that are agricultural and horticultural pests.

Sources

Every fact above was checked against these pages, and kept only where one of them states it.

• Wikipedia
• Animal Diversity Web

At a glance

About the Two-Spotted Lady Beetle

In a whirl of vibrant red and black, the Two-Spotted Lady Beetle dances across the sun-kissed petals of wildflowers, its delicate legs moving with a quiet purpose as it searches for aphids to devour. With an air of gentle determination, this tiny, spotted gem navigates the intricate landscape of leaf and stem, its compound eyes drinking in the details of its surroundings. As it flits from bloom to bloom, the lady beetle's very presence seems to embody the carefree essence of a warm summer's day, its beauty and charm woven seamlessly into the fabric of the natural world.

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