Pirate Bugs and Insidious Flower Bugs

Description of insidious flower bugs and minute pirate bugs

During the late summer, small, obscure insects known as insidious flower bugs and their rarer cousins, the minute pirate bugs, make their presence known in a very convincing manner by biting with an impact that is out of proportion with their size. Their name describes their small size and their habits.

They are about 1/5 of an inch long, oval to triangular in shape, somewhat flattened and black with whitish markings on the back. They are beneficial as predators, feeding on small insects and the eggs of other insects. For example, these bugs are an important predator of corn earworm eggs in corn fields.

Insidious flower bug
Insidious flower bug

Life cycle of insidious flower bugs and minute pirate bugs

They are present all summer in fields, woodlands, gardens and landscapes. They quietly go about their business without anyone taking notice until late in the summer when they migrate from fields and woodlands and begin the disagreeable behavior of biting humans. Their bite is surprisingly painful for such a small insect as they probe their short blunt beak into the skin. They do not feed on blood or inject a venom or saliva.

Damage caused by insidious flower bugs and minute pirate bugs

People differ in their response to the bites. Bites on some swell up like a mosquito bite, some turn red and for others there is no reaction at all. One consolation - the bugs are not quick to fly following biting, so the victim usually has the satisfaction of removing the offender from the ranks of the living.

Management of insidious flower bugs and minute pirate bugs

Control of insidious flower bugs and minute pirate bugs is not practical, in part, because their presence and abundance is temporary and variable from year to year. Further, widespread control is not desirable because of the beneficial role they have in the environment. Wearing dark clothing on very warm days when pirate bugs are abundant may help. Repellents are generally not effective though you may want to try them to see for yourself if they work or not for you.

Do you live in Iowa and have an insect you would like identified?

The Iowa State University Plant & Insect Diagnostic Clinic will identify your insect, provide information on what it eats, life cycle, and if it is a pest the best ways to manage them.  Please see our website for current forms, fees, and instructions on preserving and mailing insects.   

Contact information for each state's diagnostic laboratory for U.S. residents.  If you live outside of Iowa please do not submit a sample without contacting the Plant & Insect Diagnostic Clinic.  


Last reviewed:
October 2022

Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Yard and Garden, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on September 12, 2016. The information contained within may not be the most current and accurate depending on when it is accessed.