Insect Journal
October, 2001
Answer to this month's Insect Quiz

    1. What kind of lady beetle is this and how many different kinds are present?
      This insect is known as the multicolored Asian lady beetle. Because it is common around homes in October, it is also sometimes called the Halloween lady beetle. Despite variations in its color and the size of the spots on its wing covers, there is only one species present. The multicolored Asian lady beetle can be readily identified by the 'M' marking behind its head. In some cases this 'M' is thick, while in others it is thin or even broken. Also look for the number of spots on its wing covers; there are usually 19.

    2. Where did they come from?
      These lady beetles are native to China. No one is sure exactly how they got into this country. They were deliberately released in California in 1916 and in the 1960s for biological control of aphids. There were also releases made in the south and the east in the 1980s. However, the lady beetles apparently did not become established through these releases.

      In 1988 a population of multicolored Asian beeles was found in Louisiana. It is speculated that this population was the result of an accidental introduction by a freighter in New Orleans. From there, they spread throughout the southeastern and eastern United States. Multicolored Asian lady beetles were never released into Minnesota, but they eventually migrated into the state from adjacent areas. They were first found in Minnesota in 1995. The first major infestations around buildings occurred in 1998, and by 2000 the insect was generally dispersed throughout the state.

    3. Do these insects cause any harm?
      Fortunately, these lady beetles do no real harm and are chiefly a nuisance when thy congregate in large numbers around the outsides and insides of homes. They do not eat our food, destroy furniture or clothes, or harm people or pets. People are sometimes concerned because they may occasionally pinch the skin, but this does not cause any real injury. As a reaction to stress, lady beetles can secrete a yellow liquid that can stain surfaces.

    4. What can you do about these insects?
      When these insects are numerous, it is not possible to completely prevent them from entering homes. To minimize the problem, start by caulking and sealing obvious entry points around the exterior of the home. You may need to supplement this with an insecticide application around the exterior of your home. There are some products containing permethrin or bifenthrin that are available to the public for this purpose. You may also contact a reputable pest control service to do this job. Concentrate on the south- and west-facing exposures. Once the lady beetles find their way indoors, there are not many options except to physically remove them.





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