The Asian lady beetle, also known as Japanese ladybug in North America and Harlequin ladybird in the UK, comes in many color variations, from yellow to black. However, many have the familiar red back with black spots. The number of spots varies as much as the color, but the most common form has ten spots on each shard. To identify a lady beetle as Harmonia axyridis, look at the upper side of the thorax: Several black dots merge together to form an M-shaped marking. This marking is visible in my photograph.
Each Asian lady beetle is capable of devouring over 12,000 aphids a year. This voracious appetite is why it was introduced to North America and then Europe, in order to protect crops as a natural pest control. It established successfully and become very common.
Unfortunately, the Asian lady beetle has a very large prey-range. Its voracity allows it to eat all aphids, out-competing native ladybirds whose populations decline by starvation. Furthermore, when it runs out of aphids, it starts eating other invertebrates – other ladybird species, hoverflies, lacewings, butterflies and the like. These other species, many of them beneficial, are put at risk. This has happened in North America and is currently happening in Europe.