​​What's Hot at the PPDL

August 9, 2016

Do Not Confuse Hover Flies With Sweat Bees

Timothy Gibb, Department on Entomology, Purdue University

A population explosion of tiny flies often called a hover flies seems to be occurring in many areas of Indiana, especially near corn and soybean fields.  Hover flies often swarm around people and even land on them, presumably  looking for moisture and salts on our skin. 

These small flies are bright yellow and black in color and are often confused with sweat bees or a yellow jacket wasps, but rest assured that these are flies and not bees.

There is an old adage; two wings fun; four wings run. 

If you look closely at hover flies you will see that they have only two wings.  That means that they are in the fly group.  Flies cannot sting.

Also look for the following key behavioral and morphological differences  to separate hover flies from sweat bees and yellow jackets. 

  • Hover flies have the ability to ‘hover’ or to remain apparently suspended in mid air.  Wasps and bees do not. 

  • Hover flies do not possess stingers – thus cannot sting.   

  • Hover flies have only a single pair of wings, a hairless body, and are more brightly colored (yellow and black abdomens) when compared to sweat bees.

  • Hover flies are smaller and have fewer yellow lines on the abdomen than yellow jackets.

Hover flies are most prolific near argricultural fields: corn and soybeans.  Because they do not directly harm people, no chemical controls are recommended.  As the season progresses, we expect to see hover fly populations decline dramatically.

Related Articles:

Swarms of "Weird Worms" and "Hover Flies" Infest Indiana Corn Fields​

​Cl​ick on image to enlarge

​Figure 1
​Figure 2- Swesaat bees often have a metallic colored head and thorax

Figure 3-Yellow jackets are usually larger than hover flies and have a distinct yellow and black striped abdomen

*Photos courtesy of John Obermeyer