Why Do Ladybugs Smell?
Ladybugs actually have a certain offensive smell as a defensive mechanism. The smell has often been likened to raw potatoes, a moldy odor or burnt peanuts. The chemical that causes this, pyrazine, has an extremely strong taste as well. It is one of the main flavors for certain vegetables and other products, including green bell peppers, peanut butter, a few different types of grapes and asparagus. Interestingly enough, a tiny amount of the chemical can actually taste good, but any more significant amount will both taste and smell absolutely horrible. The smell is actually able to ruin whole crops of grapes in a vineyard, destroying the possibility of good wine that year, if the ladybugs are able to settle in and around the plants. For this reason, very specialized methods are used by vignerons, those people who grow and make the wine, for getting rid of and preventing the infestation of various pests and insects, not least among them, the ladybug.
The pyrazine is secreted from special glands in the ladybug’s legs that is not always excreted, but is when the ladybug is sensing danger. Of course, this is highly concentrated pyrazine, so that a drop that is no larger than the tip of a pin can make a huge stink. The ladybugs will also secrete the chemical if they or their nest is disturbed, so if you see a ladybug flitting around constantly, it is very likely that their strong odor will follow shortly. And of course, this is also why when a ladybug is squished that they cause an enormous stink wherever they are; all of their stored up pyrazine is release at one moment, making the air around them thick with the strong and nasty odors. If you have ladybugs in your house, be careful not to upset them, but there are available chemicals to get them to move our, available at hardware or garden stores.