Predatory bugs belong to the family Hemiptera or true bugs. This group of insects includes many pest insects, but there are also many important natural enemies. Some species are quite small, measuring a few millimeters in length, while others can be several centimeters long.
Predatory hemipterans are a diverse group made of many different species, but there are some common identifiable characteristics. They have an elongated body varying in shape from flattened to cylindrical, with well developed legs adapted for capturing and holding onto prey. Their forewings are partially hardened at the base and membranous at the tip, forming a protective shield when at rest. They possess specialized mouthparts for piercing and sucking, using a long stylet to feed on prey fluids.
There are several agriculturally important predatory bugs.
Minute Pirate Bugs (Orius sp.)
Minute pirate bugs, measuring around 2.5 mm in length, are common in crops. They have black, oval and slightly flattened bodies with light wing patches, wide heads, bulging red eyes, and prominent antennae. These bugs are most active in early spring. Minute pirate bugs are one of the first predaceous insects to begin feeding early in the growing season. They are common in many field crops and attack insect
eggs, aphids, scales, and spider mites.
Bigeyed Bugs (Geocoridae sp.)
Adults are brown or black in colour, and range from 3-5 mm in length. Adults have a triangular head with large, prominent eyes that occasionally extend over the back. They are are found mostly on low-growing plants, including many field and row crops and in gardens, and attack insect bug nymphs, beetles, insect eggs, small caterpillars, and all stages of aphids, mites, and whiteflies.
Damsel Bugs (Nabis sp.)
Adult damsel bugs are typically 8-12 mm in length and have a slender, soft-bodied structure compared to other true bugs. They feature a narrow head with prominent bulging eyes and long antennae. These brown-colored predators have strong forelegs designed for grasping prey. They are commonly present in low vegetated areas, row and tree crops, gardens, and urban landscapes and prey on many crop pests, including caterpillars, aphids, and other plant-feeding bugs.
Assassin Bugs (Reduviidae sp.)
Adult assassin bugs exhibit a size range of 4-40 mm and display a variety of colors, including brown, black, red, or orange. They are characterized by their elongated heads, slender necks, beady eyes, and hinged, needlelike mouthparts. The tip of their beak fits into a groove on their thorax, producing a distinctive sound when rubbed against ridges. These predators can be found in row and tree crops, gardens, and urban landscapes, and grasshoppers, beetles, flies, and other plant-eating true bugs are among their preferred prey.
Predatory Shield/Stink Bugs (Pentatomidae sp.)
hey are larger in size, typically measuring 8-20 mm in length, and have broader bodies compared to other true bugs. Their body shape is shield-like, displaying a flattened and somewhat triangular or pentagonal form. At rest, their wings form a characteristic X-shaped pattern. The coloration of shield bugs encompasses a range of brown, green, and gray hues, facilitating effective camouflage in their environments. These bugs are adaptable and can be found in virtually any crop where they feed on eggs, grubs and caterpillars.
Green peach aphid
Redlegged earth mite
Predatory bugs are relatively common and most can be found in a range of agricultural systems.
Creating diverse habitats with hedgerows, cover crops, brushpiles and wildflower strips can support generalist predator population, by providing additional food sources, nesting sites, and protection from pesticide exposure or extreme weather conditions.
Excessive use of pesticides can be detrimental to predatory bug populations and their effectiveness as biological control agents. Consider adopting integrated pest management (IPM) practices, which involve using pesticides judiciously and as a last resort. Targeted application of pesticides, avoiding broad-spectrum ones, and selecting insecticides that have minimal impact on non-target organisms can help preserve predatory bug populations.
While predatory bugs offer numerous benefits, their impact can vary depending on local species composition, farm management practices, and regional factors. Predatory bugs are general predators and may also feed on bees, lacewings, ladybird beetles, and other beneficial species.
It is particularly important to note that some species of predatory bugs can be omnivorous. In situations where there is a scarcity of prey or when the population of predatory bugs is relatively high, these bugs may resort to feeding on plant tissue as an alternative food source.