Minute Pirate Bug: A Good Little Bug with a Big Bite
by Jody Green, Extension Educator
Ever wonder about those small bugs that tend to bite during football season? These are minute pirate bugs, scientific name: Orius insidiosus, sometimes referred to as the insidious flower bug. For years they flew under our pest radar, but recent attention has focused on their ability to inflict a painful bite relative to their size.
As their name implies minute pirate bugs are tiny, measuring 1/8-inch in length. Their bodies are flattened and oval-shaped, with wings positioned flat over the body. They are mostly black in color, with a gold patch across the back and white tip of the wings, which extends past the abdomen. Like other “true bugs” they have piercing-sucking mouthparts used to inject digestive enzymes into prey before ingesting the liquid from the plant or animal source.
Minute pirate bugs are predators and feed on a variety of soft-bodied invertebrates, which include thrips, aphids, leafhoppers, spider mites, whiteflies, caterpillars and the eggs of other insects. Due to their generalist diet and diverse distribution, they are considered beneficial insects and biological control agents in a variety of agricultural crops, greenhouses, orchards and home gardens.
Natural enemies, like the minute pirate bug, are very important to the ecosystem. In high enough densities, they can effectively control pest species that destroy crops like corn and soybean. Minute pirate bugs are predaceous throughout their entire lives, but are omnivores and feed on plant sap and juices from flowers.
Minute pirate bugs undergo incomplete metamorphosis where the immature form or nymph resembles the adult, only smaller and without wings. They overwinter as adults in protected places such as leaf litter and plant debris. They become active in March-April and fly until October, producing two to three generations per year. Females lay 80–100 eggs in her lifetime, often in plant tissue, where they hatch four to five days later. Nymphs are teardrop-shaped, brown-orange color and lack wings. They undergo five stages of development, growing larger with each molt, which lasts two to three weeks. The oldest nymphs possess wing pads and develop wings on their final molt. Adults are highly mobile, actively searching for prey and can live for three to four weeks.
Minute pirate bugs spend the spring and summer unnoticed, staying close to plants with attractive flowers. Once fall comes, their bites cannot be ignored. They land on the exposed skin of humans and will use their short, blunt mouthparts to probe and puncture our skin. They do not feed on human blood, nor do they inject saliva or venom. Some people react to bites with redness or a welt and others have no reaction. Minute pirate bugs are slow to respond and are easily squished.
It is not practicable to control minute pirate bugs. Insecticidal treatment to plants harm these predators and consequently increase plant pests. Unfortunately, the use of insect repellent is not effective at minimizing bites. The good news is minute pirate bugs do not transmit pathogens, survive or reproduce indoors. Predators of the minute pirate bug include spiders, lacewings and other predaceous true bugs.
Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the University of Nebraska–Lincoln is implied. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office