Orius insidiosus, also known as the minute pirate bug, is native to North America and a beneficial insect (Figure 1). They are generalist omnivores, feeding on other insects and pollen. Minute pirate bugs belong to the Order of true bugs — Hemiptera — in the family Anthocoridae. Orius insidiosus can be found in a wide range of crops, pastureland, trees, shrubs, weeds, and on many wild plants. They inhabit the stems, foliage, and flowers of plants and spread fast when prey are available. This bug is an important contributor to the suppression of various agricultural pests in greenhouses, high tunnels, and open-field environments.
Figure 2. The various life stages of Orius Insidiosus: egg, nymphal stages, and adult. For brevity, we did not picture the 2nd and 4th instar (illustration created by Skarleth Chinchilla and Inspired by Morgan Mahana – Sound Horticulture 2024).
Life cycle
There are numerous generations of Orius insidiosus each year. Like all hemipterans, they undergo incomplete metamorphosis. An adult female can lay up to 100 eggs in her lifetime. Orius insidiosus can complete its life cycle in approximately 23-25 days at 70°F (21°C). Its growth and development can be affected by cooler temperatures or lack of prey. Adult females deposit their eggs within plant tissue. Eggs are typically laid 3-5 days after mating occurs. Upon hatching, they develop through five nymphal stages, looking similar as they grow but increasing in size (Figure 2). The nymphs are bright orange in color, and you can begin to see the wing pads develop as they grow. The fifth instar develops into an adult with fully developed wings. Adults live for approximately 21-28 days.
Habitat
Orius insidiosus can be found in a wide range of crops, natural habitats, and is also commercially available to be used in augmentative biological control. They are attracted to flowers and plants that are infested with small soft-bodied insects. Orius insidiosus also feeds on pollen (Figure 3) and plant sap. Feeding damage in plants is minor and this omnivorous feeding behavior is essential to preserve a healthy population when prey is not available.
Natural biological control from Orius Insidiosus
Orius insidiosus is one of the most used Orius species in biological control programs. They are effective predators and can decrease pest populations in various agricultural systems. They feed on any small soft-bodied insect, including thrips, mites, aphids (Figure 4), whiteflies, leafhoppers, various insect eggs, and tiny newly hatched caterpillars. Both immature and adult forms can feed on numerous prey items daily. Orius insidiosus have been shown to effectively suppress populations of spider mites on bean plants and attacks and kills all stages of thrips.
Figure 3. Orius Insidiosus feeding on pollen (Photo by John Obermeyer).
Figure 4. Orius Insidiosus preying on aphids(Photo by John Obermeyer).
Conservation of Minute Pirate Bugs
Some practices can be implemented in agricultural production systems to promote and conserve natural enemies like Orius. One practice is to avoid the use of broad-spectrum insecticides. It is also helpful to maintain flowering annuals and perennials, shrubs, and trees near crop fields that provide protection and alternative food sources for these insects. Orius Insidiosus is attracted to small white and yellow flowers and there is some evidence to suggest that they respond positively to the commercially available herbivore-induced plant volatile lure, Preda-lure. Take caution if you plan to implement them in tomato, they get stuck in the sticky hairs (glandular trichomes) that the plant produces.