OCTOBER
2005

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

10-13-05

Little Insects Turn Out to be Big Biters

Humans have long been unwilling donors of blood to biting insects. Female mosquitoes are the best known of the six-legged phlebotomists. Because of the blood-sucking habit, mosquitoes are capable of transmitting disease-causing organisms between animals. In scientific terms, they are disease vectors.

Mosquitoes transmit the well-known diseases of malaria, yellow fever, St. Louis encephalitis, and West Nile . But mosquitoes are not the only insects that seek blood meals from humans. The kissing bug gets its name because of the habit of selecting the area of the mouth to grab a sip or two of human blood. Bed bugs aren't as specific as to feeding site. Any old patch of human skin is a possible feeding site for this nighttime feeder.

In general, these insect blood letters go about their business with a minimum amount of discomfort to the human. We may not even notice that we have become a blood donor until the donation site begins to itch.

That is not the case with other blood-feeding insects. When these insects bite, the animal knows it! Horse flies, deer flies and stable flies produce pain when they bite. That is why animals, including the human animal, respond to the bite with avoidance behavior. Stomping, running, swatting, and, in the case of humans, swearing, are common reactions to bites from these insects.

This is also why insects that produce pain when they bite are nervous feeders. These insects tend to bite and fly. This is because these insects know that their victim will respond to the bite. And this response might not be healthy to the biting insect.

Some of the pain-producing insect biters are very tiny creatures. The group known as punkies or no-see-ums fit into this category. These are flies. Their small size is responsible for the name "no-see-um." The bite of these little insects is definitely out of proportion to their size. In fact, their scientific name "Ceratopogonidae" is a very big word for such small insects. Depending on the type size, you could place from 15 to 30 of the little biters head to tail along their name!

Many of the no-see-ums attack other insects from which they suck hemolymph, the insect blood. Even that notorious insect predator the praying mantid has been observed being attacked by no-see-ums. Some Ceratopogonids prey on smaller insects.

This is also the case with the insect known as the minute pirate bug. This insect is a true bug, but the name minute suggests that it is small. And it is. It's about the size of the period at the end of this sentence. This bug is a predator on other insects. It is commonly found in crop fields where it feeds on the plant pests known as aphids. For that reason, the minute pirate bug is considered a beneficial insect.

The minute pirate bug is also known as the insidious flower bug. That name comes from the insect's scientific name Orius insidiousis. Thomas Say named that insect. Say spent the last years of his life living and working in New Harmony , Ind. , where he classified and assigned genus and species names to many insects.

The name that Say assigned to this insect is very descriptive of the habit of the diminutive bug. Orius has to do with the mouth, and insidious is defined as " full of plots, watching for an opportunity to entrap, treacherous." In other words, this insect is a treacherous biter.

In 2005, populations of the minute pirate bug appeared to be very high. In the fall, the insect leaves the crop fields, searching for places to spend the winter. This means the insect shows up around houses and in parks and comes into contact with humans. For reasons that we don't understand, this little black insect with two white spots seems to relish taking a bite out of human flesh. The bite hurts and justifies the name of insidious biter. Oh, well, things could be worse -- it could be a much bigger bug!

 

Writer: Tom Turpin
Editor: Olivia Maddox