Living rooms invaded by ladybugs:
"Simply show them the door“, says a biologist of the University of Hohenheim. [10.11.11]
Aggressive, die hard, and equipped with a strong reproductive urge: Asian ladybugs are conquering the habitats of local species. It seems unlikely, however, that the indigenous species will become extinct.
Swarms of freckled ladybugs descend on and cling to balcony doors and windows or even entire living rooms. The Asian variety of ladybug, harmonia axyridis, has been expanding its foothold in Europe for a good ten years. More recently, the bringer of good luck has started commandeering living quarters during the winter months on an ever-increasing scale.The only remedy for those unwilling to share their accomodation, according to Prof. Dr. Johannes Steidle from the Department of Animal Ecology at the University of Hohenheim, is to show the ladybugs to the door. To have a bad conscience is unnecessary since the little creatures can well survive out in the cold.
According to Prof. Dr. Steidle, the Asian ladybugs were originally introduced into local habitats as a kind of natural pesticide. "It was also let loose in Germany since it has a voracious appetite for plant lice“ in addition to its formidable reproductive and survival qualities. Sooner or later, "the Asian ladybug simply took off and started to multiply in the wild".
Successful immigration: "well-adjusted to life in the city“
Being aggressive, die hard, and equipped with a strong reproductive urge, the Asian ladybugs from Japan and China are not only conquering the habitats of indigineous ladybugs, but they are also "making a meal out of these local species to a certain degree", says Prof. Dr. Steidle.
Currently there is no effective method for preventing the further expansion of the foreign species. In contrast to the local ladybug, they are even immune to certian insect-killing fungi.
The Asian ladybug is apparently also not afraid of living in discomfort, as is evident from its prevalence in uncommon habitats, such as in cities.
Extinction is unlikely
It is too early to tell whether or not the Asian ladybug will turn into a real menace. "It's true that they do multiply quickly. Naturally the issue of a plague all depends on the creatures' access to natural resources, such as how much food and space are available to ensure their survival".
The animal ecologist is also not overly concerned that the indiginous species could become extinct at the hands of the invader. "I wouldn't go so far as to talk of extinction, but the local species are definitely on the retreat", he says.
And the new ladybug is fast. "My colleague, Till Tolasch, first observed the Asian species in Hamburg ten years ago. At least 90% of ladybugs in collection samples were of foreign origin. Today we see swarms of them clinging to the windows of homes around Stuttgart".
Colourful and winterproof
Asthetically speaking, Prof. Steidle finds the Asian ladybug with its wider array of colours "even prettier" than the local European ladybug. With their mixtures of black with red dots and yellow with black dots and black with yellow dots "they do, after all, also go by the name of harlequin ladybug".
Yet if you are reluctant to share your living room with these freckled guests, you can, in all good conscience, simply round them up and throw them out. "They are used to winter's cold", Prof. Dr. Steidle says "and will simply have to find other lodging for the winter".
Text: Mayer / Klebs, Transl.: O'Mealy
Contact for press:
Prof. Dr. Johannes Steidle, Universität Hohenheim, Fg. Tierökologie, Tel.: 0711 459-23667, E-mail: jsteidle@uni-hohenheim.de