Predatory beetle Adalia
If you are looking for the perfect pest control, look no further than the Adalia bipunctata predatory beetle. This tiny beetle is native to Europe and Asia, but is found all over the world. Adalia bipunctata is a voracious predator of aphids and other small insects, making it an invaluable ally in the garden. In this blog post, we take a closer look at what makes Adalia bipunctata so special, and how you can attract them to your garden.
How do you recognise the Adalia bipunctata predatory beetle?
Adalia bipunctata, also known as the two-toed ladybird or two-toed ladybird, is a small coccinellidae beetle. It has a black body with two red spots. Adults are oval-shaped and about 3 mm long. They are red or orange with two black spots on their wing feathers. Larvae are crocodile-shaped, dark grey or black with orange or yellow markings, and about 6 mm long. Pupae are reddish-brown and about 5 mm long.
The life cycle of Adalia bipunctata
Adalia bipunctata has a multivoltine life cycle, meaning that it can reproduce several times in one season. The duration of each life stage varies depending on temperature, but the entire cycle usually lasts 30-50 days. Eggs are laid singly or in clusters on the underside of leaves. The larvae hatch after 3-5 days and immediately start feeding mainly on aphids, as well as other small insects and mites. After 10-14 days of growth, the larvae pupate in a thin silk cocoon attached to a leaf or other surface.
Adult beetles emerge from the pupae after 7-10 days and mate soon after. Females lay eggs for the next generation, while males die within a few weeks.
Adalia bipunctata as biological control
Adalia bipunctata, better known as the two-spotted ladybird or two-spotted ladybird, is an important predator of aphids and other small soft-bodied insects. They are native to Europe and were introduced to North America in the early 1900s for biological control of aphids. The "two-spot" ladybird is now widespread across the continent.
How long does the population of predatory beetles persist?
Adult ladybirds overwinter in protected places such as under tree bark or in leaf litter. In spring, they emerge and start feeding on aphids and other small soft-bodied insects. Females lay eggs singly or in small groups on the underside of leaves near aphid colonies. The eggs hatch after 3-5 days into larvae that immediately start feeding on aphids. The larvae go through four stages (growth stages) and moult after each stage. The entire life cycle from egg to adult takes 4-6 weeks, depending on temperature and food availability.
Which pests prey on this predatory beetle?
Ladybirds with two spots are important predators of aphids and other small soft-bodied insects, such as:
- scale insects
- white flies
- moth eggs.
A single adult predatory beetle can consume up to 60 aphids a day! Ladybird beetles can reduce populations of serious crop pests such as the green peach aphid (Myzus persicae) by up to 80%.
This can protect crops from damage and reduces the need for chemical insecticides that can harm beneficial insects such as honey bees (Apis mellifera).
More benefits of Adalia bipunctata
Adalia bipunctata is not only a voracious eater of crop pests, but is also an important part of the food chain itself! Birds, bats, spiders and even some fish eat ladybirds - making them an important link in terrestrial ecosystems.
Adalia bipunctata is not only a valuable part of the food chain, but also provides a number of environmental benefits simply by being present in an ecosystem.
Adult ladybirds give off pheromones that attract mates and repel predators, preventing them from becoming prey themselves. These pheromones can also have a negative effect on certain species of parasitic wasps, reducing their ability to parasitise pests such as aphids. By preventing these parasites from finding their hosts, Adalia bipunctata indirectly helps control pest populations.
The perfect habitat for Adalia bipunctata
To attract Adalia bipunctata into your garden, you need to provide a habitat that meets their needs. They prefer areas with plenty of sunlight and some shelter from the elements. A good way to provide this is by planting native plants that create a dense canopy. This gives them the food and shelter they need, while also giving them a place to lay their eggs.
The best food for Adalia bipunctata
Adalia bipunctata are attracted to gardens with a variety of flowering plants. They feed on the nectar from these flowers, so it is important to have a variety of flowering plants that provide them with food throughout the season. Some examples of good flowers to plant are daisies, marigolds and zinnias.
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