The Multicolored Asian Lady Beetle: Welcome Guest or Home Invader? -- by Allison Bloechl -- Muhlenberg College Class of 2014

As a kid I always remembered loving Lady Beetles.  I used to see them frequently as a child but now I am hard pressed to remember the last time I saw one that was native.  You’re probably thinking to yourself, I saw a Lady Beetle just the other day.  Well, you did, but not a native species.  What you saw was most likely an invasive Multicolored Asian Lady Beetle, Harmonia axyridis.  Mistaking the foreign beetle for its native relative is easy as they look quite alike.  While very similar in function and appearance to the native Lady Beetle, which comes in red only, the Multicolored Asian Lady Beetle can be any color from yellow to red, but will most likely be somewhere in the orange spectrum. 

So how did the Multicolored Asian Lady Beetle get here?  It was introduced as early as 1916 as a type of natural pesticide and was used to help control aphid populations.  However, it wasn’t until the late eighties in Louisiana that the Asian Lady Beetle was noticed in large numbers.  By 1993, the species was established in Pennsylvania and shortly thereafter became a noticeable presence here in Allentown.

Here’s where a problem arises: while the Multicolored Asian Lady Beetle might be cute in your backyard, it has the potential to become a significant household pest. One, two or even five Lady Beetles in your home might seem at most a nuisance, but, if your winter is exceptionally cold and you are exceptionally unlucky, you can get an infestation. 

But do not worry!  Multicolored Asian Lady Beetles will NOT cause any significant damage to you or your property.  There are, however, a couple things to know to make dealing with an infestation easier.  When agitated or crushed, the beetles can “reflex bleed,” that is, emit a foul smelling yellow chemical from their legs. While this chemical is not harmful, it will stink up the place and potentially stain, so, if you do find an unwanted Multicolored Asian Lady Beetle, squishing is not recommended. 

Besides their stinky juice, Multicolored Asian Lady Beetles have another defense – their bite.  While this might be unpleasant, there are no real side effects to a Lady Beetle bite.  The only time a bite will become problematic is if the person being bitten has an allergy to the insect’s saliva.  Fortunately such allergies are highly uncommon.

The first thing to do if you notice an infestation in your home is to NOT APPLY CHEMICAL PESTICIDES.  Spraying pesticides in your home causes a huge health risk as the chemicals can be inhaled or ingested, potentially causing serious internal damage depending on the pesticide used.  These chemicals can also harm your eyes and skin, maybe even permanently.  Do-it-yourself chemical pesticides are never the answer for these insects.

There are easy, safe and cost-effective ways to deal with a Lady Beetle infestation.  Vacuuming the insects is a plausible option, but more often than not they will reflex bleed during the process, smelling up your vacuum, and by proxy, your home.  The tried and true broom-and-dustpan technique also works and is easy on your budget.  A high-tech option for the removal of these creatures is the recently developed light traps made specifically for insects like the Multicolored Asian Lady Beetle.  As these creatures are attracted to light and light colors (the lighter the house, the higher the chance of infestation) and these traps are safe for domestic use. 

Yet another way to get rid of any infestation is to avoid it in the first place.  While the Multicolored Asian Lady Beetle is attracted to light colored structures, painting your house might not be the most practical preventative method.  Ensuring that your house is well-sealed and that windows and doors are installed properly is a good method to prevent any insect infestation.  By making sure they have no way to get into your house, there is no way for them to gather en mass. Fortunately, there is plenty of information out there to prevent and solve infestation problems.

Since the biggest issue with the Multicolored Asian Lady Beetle – infestation – seems easily prevented and treatable, why all the fuss?  Well, since the populations of the Multicolored Asian Lady Beetle became strong in the late eighties/early nineties, the native population of North American Lady Beetles has declined, though the two have yet to be causally linked.  “So what?” you might ask.  As long as the Asian Lady Beetle fulfills the niche (or environmental job) of the native Lady Beetle, does it really make that much of a difference?  

Interestingly enough, the Multicolored Asian Lady Beetle is a phenomenal example of the value of biodiversity and why it is important to preserve it.  Scientists have discovered that Harmonia axyridis’ hemolymph (or insect blood) contains powerful and important antimicrobial properties.  Known as Harmonine, this chemical has been scientifically proven to fight off infection and is known to have anti-malarial activity. With such a wealth of medical properties in just one species, one wonders what other properties can be found in the native North American species, close cousins to the Multicolored Asian Lady Beetle.

Declines in native Lady Beetle populations can be explained by many different factors – invasive competition, the creation of new broad-spectrum pesticides, habitat destruction or all of the above.  What is certain is that native Lady Beetles, like the Multicolored Asian Lady Beetle, have many beneficial qualities.  Both the Multicolored Asian Lady Beetle and our native lady bugs serve as natural pest control for aphids. Like the Multicolored Asian Lady Beetle, the native Lady Beetle could contain medicinal properties, or some other property we’ve yet to discover that could be highly beneficial!

The Multicolored Asian Lady Beetle: Welcome Guest or Home Invader? by Allison Bloechl is licensed under a Creative Commons Attribution 4.0 International License.