True bug fact sheet | Field of Mars EEC

What are true bugs?

True bugs are insects in the order Hemiptera, suborder Heteroptera. This group includes insects such as shield bugs, stink bugs, assassin bugs and water striders. They have six legs, antennae and piercing-sucking mouthparts called a rostrum. Their front wings are usually partly hardened and partly transparent, and they are usually held flat over the body when at rest. Hemiptera also includes other groups such as hoppers and aphids, so not every hemipteran is a true bug. An illustration of a cotton harlequin bug. A cotton harlequin bug.

Fast facts – True bugs

Scientific group – True bugs are insects in the order Hemiptera, suborder Heteroptera.

Appearance – They have a head, thorax and abdomen, six legs, antennae, a rostrum and forewings that are hardened at the base and membranous at the tips.

Size – True bugs range from less than 1 millimetre to about 75 millimetres long.

Diet – Most true bugs suck juices from plants, but some are predators and a few feed on animal blood.

Habitat – True bugs live on leaves, stems, flowers, bark, rocks, logs, leaf litter and freshwater surfaces.

Life cycle – True bugs have incomplete metamorphosis. They hatch from eggs into nymphs that look like small wingless adults and moult as they grow.

Adaptations – Piercing-sucking mouthparts, camouflage, warning colours, strong smells and specialised body shapes help different true bugs survive.

Adult cotton harlequin bug resting on a branch. An adult cotton harlequin bug feeds by piercing stems and sucking plant juices.

Where do true bugs live?

True bugs live in many habitats, including forests, woodlands, gardens, wetlands and urban areas. Some live on leaves and stems, some hide under bark or among leaf litter, and some live on the surface of freshwater. At Field of Mars Reserve, true bugs are likely to use shrub habitats, tree habitats, leaf litter and water habitats depending on the species.

Water striders standing on the surface of still water. Water striders are true bugs that hunt on the surface of still water.

What do true bugs eat?

Most true bugs are herbivores that feed by piercing plant tissues and sucking liquid food. The rostrum contains fine structures for cutting and feeding, and saliva is sent into the food source before the liquid food is sucked back up. Some species, such as cotton harlequin bugs and crusader bugs, feed on shoots, stems and other plant parts. Others, such as assassin bugs, are predators that pierce prey and suck out the digested fluids. Water striders are predators too, feeding on small animals trapped on the water surface.

Common assassin bug resting on foliage. Common assassin bugs are predatory true bugs that pierce prey with their rostrum.

What is the life cycle of a true bug?

A true bug begins life as an egg. It hatches into a nymph, which looks like a small, wingless version of the adult. As it grows, the nymph moults several times before becoming an adult. This is called incomplete metamorphosis because there is no caterpillar or pupa stage. In some species, such as the cotton harlequin bug, the female may guard the eggs until they hatch.

Female cotton harlequin bug guarding a cluster of eggs on a plant stem. Some female true bugs, such as cotton harlequin bugs, guard their eggs until they hatch.

Group of crusader bug nymphs clustered on stems. True bug nymphs look like small wingless adults and moult as they grow.

What adaptations do true bugs have to help them survive?

True bugs have many adaptations that help them survive. Their rostrum allows them to pierce plants or prey and feed on liquids. Many species use camouflage, warning colours or strong smells for protection. Crusader bugs can produce a strong smell to deter predators. Cotton harlequin bugs are brightly coloured jewel bugs, and their enlarged scutellum covers the wings, which can make them look a little like beetles. Water striders have long legs that let them skate on the water surface. Assassin bugs are adapted for hunting, using ambush behaviour and saliva that immobilises prey.

Brown crusader bug resting on green leaves. Colour, body shape and strong smells help some true bugs avoid predators.

Why are true bugs important?

True bugs are an important part of food webs. Plant-feeding species move energy from plants into the food chain, while predatory species such as assassin bugs and water striders help control other invertebrates. Some true bugs can damage crops or garden plants, but many are simply part of the biodiversity of bushland, gardens and freshwater habitats.

Crusader bug nymph on a green leaf. True bugs are part of food webs as both plant feeders and prey for larger animals.

How can you help true bugs?

Based on the habitats and feeding roles described above, you can help true bugs by protecting native plants, keeping some leaf litter and bark habitat, caring for ponds and creeks, and avoiding unnecessary broad-spectrum insecticides. Planting a variety of local species can also help because different true bugs feed, hunt or shelter on different plants and in different microhabitats.

Bushland with trees, grasses, fallen leaves, sticks and logs providing habitat for many animals. Protecting bushland helps true bugs and many other invertebrates.

More invertebrate fact sheets

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Attributions

References

Australian Museum. n.d. What do true bugs look like? [online] Available at:

https://australian.museum/learn/species-identification/ask-an-expert/what-do-true-bugs-look-like/

Australian Museum. n.d. Cotton Harlequin Bug. [online] Available at:

https://australian.museum/learn/animals/insects/cotton-harlequin-bug/

Australian Museum. n.d. Crusader Bug. [online] Available at:

https://australian.museum/learn/animals/insects/crusader-bug/

Australian Museum. n.d. Feather-legged Assassin Bug. [online] Available at:

https://australian.museum/learn/animals/insects/feather-legged-assassin-bug/

Australian Museum. n.d. Green Vegetable Bug. [online] Available at:

https://australian.museum/learn/animals/insects/green-vegetable-bug/

CSIRO. n.d. Hemiptera - bugs, aphids, cicadas. [online] Available at:

https://www.ento.csiro.au/education/insects/hemiptera.html

Museums Victoria. n.d. Gerridae, Water Strider. [online] Available at:

https://collections.museumsvictoria.com.au/species/8477

Queensland Museum. 2021. These true bugs are a treasure. [online] Available at:

https://blog.qm.qld.gov.au/2021/08/04/these-true-bugs-are-a-treasure/

Image attributions

A cotton harlequin bug – Field of Mars EEC (original illustration).

An adult cotton harlequin bug feeds by piercing stems and sucking plant juices – “File:CSIRO ScienceImage 154 Tectocoris diophthalmus the Cotton Harlequin Bug.jpg” by CSIRO. Creative Commons Attribution 3.0 Unported licence. Available at: https://commons.wikimedia.org/wiki/File:CSIRO_ScienceImage_154_Tectocoris_diophthalmus_the_Cotton_Harlequin_Bug.jpg.

Water striders are true bugs that hunt on the surface of still water – “File:Water strider.jpg” by TimVickers. Released into the public domain by the copyright holder. Available at: https://commons.wikimedia.org/wiki/File:Water_strider.jpg.

Common assassin bugs are predatory true bugs that pierce prey with their rostrum – “File:Pristhesancus plagipennis 423277931.jpg” by Sofia Zvolanek. Creative Commons Attribution 4.0 International licence. Available at: https://commons.wikimedia.org/wiki/File:Pristhesancus_plagipennis_423277931.jpg.

Some female true bugs, such as cotton harlequin bugs, guard their eggs until they hatch – “File:Tectocoris diophthalmus (female adult with eggs - dorsoolateral).jpg” by Norbert Fischer. Creative Commons Attribution-Share Alike 4.0 International licence. Available at: https://commons.wikimedia.org/wiki/File:Tectocoris_diophthalmus_(female_adult_with_eggs_-_dorsoolateral).jpg.

True bug nymphs look like small wingless adults and moult as they grow – “File:Crusader Bug instars (Mictis profana) (23610154572).jpg” by Patrick_K59. Creative Commons Attribution 2.0 Generic licence. Available at: https://commons.wikimedia.org/wiki/File:Crusader_Bug_instars_(Mictis_profana)_(23610154572).jpg.

Colour, body shape and strong smells help some true bugs avoid predators – “File:Crusader bug (6256927949).jpg” by John Tann. Creative Commons Attribution 2.0 Generic licence. Available at: https://commons.wikimedia.org/wiki/File:Crusader_bug_(6256927949).jpg.

True bugs are part of food webs as both plant feeders and prey for larger animals – “File:Mictis profana (16370289341).jpg” by Graham Wise. Creative Commons Attribution 2.0 Generic licence. Available at: https://commons.wikimedia.org/wiki/File:Mictis_profana_(16370289341).jpg.

Protecting bushland helps true bugs and many other invertebrates – Field of Mars EEC (original image).

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