Not all ladybugs are happy beetles – tierwelt.ch

«Himugüegeli», «Herrgotschäferli» and «Glöckschäferli»

Lucky beetles are considered useful insects in the garden. But there are also invasive species among them.

There are over 80 different species of ladybugs in Switzerland and they can come in a wide variety of colors. The head, chest and underside are mostly black. However, some species also have a light or rusty brown underside. In Switzerland, the two-point ladybug (Adelia bipunctata) is the most famous. Red with two black dots or black with two red dots – these are his typical colors. However, there are various intermediate forms with black or red spots. The seven-spot ladybug (Coccinella septempuncta) is slightly larger than the two-spot ladybug and has a classic seven-speckled appearance.

“Fortune beetles” for gardeners

Although the coloration of ladybugs varies, they are all conspicuous and serve as a warning signal to predators. In distress, ladybugs secrete a yellowish fluid from the blood that contains toxic substances. The blood of happy beetles is also unpleasantly bitter, so they eat less.

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Ladybug eats up to 50 lice a day. It mainly feeds on aphids and scales, mites, beetles, and among them also butterfly larvae. Two-point ladybugs can also be used as pest control.

Asian pest control

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Asian relatives of the colon beetle are even more productive at eating pests. It comes from Japan and China. According to Umweltberatung Luzern, the Asian ladybug (Harmonia axyridis) was released in the USA and after 1982 also in Europe as biological pest control. However, pest controllers have left greenhouses and are threatening native species of ladybugs such as the two-point or seven-point ladybug. The first Asian ladybug was spotted in Switzerland in 2006 and has multiplied greatly since then. It is considered an invasive species and is illegal to release in this country.

It is the same size as the seven-branched ladybug, but its color can usually be distinguished from the locals. They are mostly yellow or orange and, according to “Umweltberatung Luzern”, have 19 black dots on the elytra. However, they can also have other colors such as red, dark red or black. There are also those without black dots or with two black dots. It is best recognized by its pronotum, with the characteristic black M. There are, however, other color variants, and even completely black beetles.

The most similar to the Asian one is the native ladybug “Anatis ocellata”. However, the native species has white markings on a black background in the prepitium, the Asian species has the opposite, it has black markings on a white background.

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The spread of the exotic

Asian ladybugs are hardy, according to Schweizergarten. However, it owes its spread to another factor: parasites. The ladybug larvae eat not only the aphids, but also their kind. The Asian ladybug is affected by a fungus-like parasite. However, the body of the Asian ladybug can stop this parasite. However, if an infected Asiatic larva is eaten by a native ladybug, the latter will die from the parasite.

Strengthening native species

According to Schweizergarten, no insecticides should be used to limit the spread of the Asian ladybug, as native and invasive species share the same ecological niche and both suffer from it. A varied garden with native plants, flowering meadows and species-rich perennials is a better way to protect and promote native species.

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