OCTOBER
2001

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

10-25-01

Ladybugs Are Notorious Halloween Trick or Treaters

Some people call them Halloween beetles. This might be due to their color pattern - orange with black spots. But these beetles also show up during the last half of October, just in time to play tricks on homeowners everywhere. So to name them after the halloween celebration seems appropriate.

Halloween beetles are actually ladybird beetles. They are also known as ladybugs. There are several hundred types of ladybugs found throughout the world, and the Halloween beetle is just one of them. Ladybugs are generally considered to be beneficial insects. that's because the feed on aphids. Aphids are plant pests that farmers and gardeners have come to hate.

Ladybug is a name that is based on an ancient perception of how helpful these insects can be. The insect grained the name back into he Middle Ages when bold knights, dreary castles and damsels in distress were commonplace. Farmers of the Middle Ages, like farmers today, had trouble with insects damaging their crops. Especially troublesome pests were aphids on the flax crop. So when aphids appeared on the flax, the people would go to church and pray for help. There weren't any insecticides or pest control companies during those days!

Almost always the prayers of the people were answered when beetles showed up and started eating the aphids. Consequently, the beetles were considered to be bugs sent by "Our Lady the Virgin Mary." The beetles became known as "Our Lady's Bug!" Today, the name has been shortened to ladybug.

Almost all of the insects known as ladybugs are predators on aphids and have come to be regarded as beneficial insects. One common exception, however, is the Mexican bean beetle which has taken up the habit of feeding on plant leaves.

Enter the Halloween beetle.

To be sure, this ladybug eats aphids. And that is good. But the Halloween beetle has a nasty little habit of wanting to spend the winter in our homes. Many of us draw the line when insects want to share our homes - even if the insect is one that we like to have in our gardens.

The Halloween beetle is officially known as the multicolored Asian lady beetle. It is a species that is native to Western Asia. In its native habitat, the Asian lady beetle, like other ladybeetles, migrates to overwintering sites. The Asian lady beetle spends the winters in great numbers in light-colored, rocky cliffs in its native area. Unlike many other lady beetles, the Asian lady beetle varies greatly in its color pattern. It ranges from light yellow to orange to red to black. It also is marked with various numbers of sots on its wing covers.

The scientific name of this insect, Harmonia axyridis, is descriptive of its congregating habit and its color variation. The genus name Harmonia suggests the rather congenial clustering habit of the overwintering beetles. The species name axyridis is based on the colors of the rainbow, reflecting the wide variation in color patterns that exist.

So why has a lady beetle with such a warm-and-fuzzy scientific name become a pest here in the United States? The insect has been very successful, so there are lots of beetles each fall. When these beetles seek a place to overwinter, they frequently are attracted to our homes. They manage to find their way into houses and, once inside, crawl around producing an odor and leaving beetle specks hither and yon.

The Halloween beetles show up in great numbers around Halloween but they will be drawn out of hibernation to filter into the living quarters of the house all winter long. And that, to most homeowners, is a Halloween trick that lasts far to long!

 

Writer: Tom Turpin
Editor: Olivia Maddox