Difference Between Bugs and Insects

Main Difference – Bugs vs Insects

Bugs and insects are two synonyms used for arthropods with more than two legs, wings, and large eyes. However, there are some anatomical differences between bugs and insects. All bugs are insects but, all insects are not bugs. True bugs belong to the order Hemiptera under the class Insecta. The main difference between bugs and insects is that bugs are the insects having proboscis, which can be used to suck food whereas insects have other mouthparts adapted for chewing or sponging. Mandibles, maxilla, and labium are the mouthparts of the chewing insects. Labellum is a mouthpart found in the sponging insects. Shield bug, aphids, leafhoppers, planthoppers, cicadas, bed bugs are examples of bugs. Butterfly, beetle, bee, ant, fly, termite, grasshopper, true bugs, and louse are examples of insects.

Key Areas Covered

1. What are Bugs
– Definition, Characteristics, Examples
2. What are Insects
– Definition, Characteristics, Examples
3. What are the Similarities Between Bugs and Insects
– Outline of Common Features
4. What is the Difference Between Bugs and Insects
– Comparison of Key Differences

Key Terms: Arthropods, Bugs, Hemiptera, Insects, Jointed Appendages, Mandible, Proboscis, Wings

What are Bugs

Bugs refer to a group of insects that feed by sucking plant or animal fluids. They belong to the order Hemiptera under class Insecta. Most bugs live in terrestrial habitats, but some live in freshwater habitats as well. Around 90,000 bugs can be identified worldwide. Bugs show incomplete metamorphosis. The three stages of the life cycle are egg, larva/nymph, and adult. The most characteristic feature of bugs is the sucking mouthparts. The sucking mouthparts are called proboscis. Bugs also have two pairs of wings. The front wing is thick and colored. It hides the other pair of wings, which are thin and clear. The other characteristic feature of bugs is the six, jointed appendages. Bugs with the above-mentioned characteristics are called ‘true bugs’. A fly with sucking mouthparts is shown in figure 1.

Figure 1: A Fly with Sucking Mouthparts

The four suborders of the Hemiptera are Heteroptera, Auchenorrhyncha, Sternorrhyncha and Coleorrhynca. Heteroptera consists of shield bugs, bed bugs, stink bugs, water striders, and assassin bugs. Auchenorrhyncha consists of cicadas, leafhoppers, and planthoppers. Sternorrhyncha consists of aphids, whiteflies, and scale insects. Coleorrhynca consists of moss bugs and beetle bugs.

What are Insects

Insects are a small type of invertebrate animals that belong to the class Insecta under the phylum Arthropoda. Around six to ten million insect species can be found in the world. They are relatively small in size and are well adapted to their environment. Most insects live in terrestrial environments. The body of insects consists of three segments: head, thorax, and abdomen. The head consists of a pair of compound eyes and a pair of antennae. One or two pairs of wings are connected to the thorax. Three pairs of legs are connected to the abdomen. The body is covered with an exoskeleton, which is made up of chitin. Different types of insects are shown in figure 2.

Figure 2: Insects

Insects undergo complete metamorphosis. The four stages of the life cycle are egg, larva/nymph, pupa, and adult. The three types of feeding mechanisms of insects are chewing, sucking, and sponging. Chewing insects have mouthparts such as mandibles, maxilla, and labium. Sucking insects are called true bugs. Sponging insects secrete saliva on the solid food and the solution is drawn up by the mouth.

Similarities Between Bugs and Insects

Both bugs and insects belong to the class Insecta.
Both bugs and insects are triploblastic, haemocelomic, invertebrate animals with bilateral symmetry.
Both bugs and insects consist of three pairs of jointed appendages since they belong to the phylum Arthropoda.
Both bugs and insects are composed of two pairs of wings.
Both bugs and insects are composed of compound eyes and two antennae in the head.
Both bugs and insects are mainly terrestrial.
The body of both bugs and insects is segmented into a head, thorax, and abdomen.
Both bugs and insects are composed of a chitinous exoskeleton.
Both bugs and insects have a complete digestive system.
Both bugs and insects have an open circulatory system.
Both bugs and insects are cold-blooded animals.
The excretion of bugs and insects occurs through Malpighian tubules.
The nervous system of both bugs and insects is composed of a brain and a ventral nerve cord.
Both bugs and insects are unisexual animals i.e. both sexes are separated.

Definition

Bugs: Bugs are a group of insects that feed on sucking plant or animal fluids.

Insects: Insects are a group of arthropods whose body is divided into three segments (head, thorax, and abdomen) with three pairs of legs and one or two pairs of wings.

Significance

Bugs: Bugs are a certain type of insects.

Insects: Insects are a group of arthropods with jointed appendages.

Scientific Classification

Bugs: Bugs belong to the order Hemiptera.

Insects: Insects consist of several orders.

Mouthparts

Bugs: Bugs have sucking mouthparts.

Insects: Insects have sucking, chewing, or sponging mouthparts.

Diet

Bugs: Bugs have a liquid diet. Most bugs are plant-feeders (nectar/sap). Some bugs feed on animal fluids as well.

Insects: Insects eat a wide range of plant and animal materials.

Wings

Bugs: The front wing of bugs is thick and colored while the hind wings are thin and clear.

Insects: Insect do not have hind wings; their wings are thin and colored or clear.

Metamorphosis

Bugs: Bugs show incomplete metamorphosis (egg, larva/nymph, adult).

Insects: Insects show complete metamorphosis (egg, larva/nymph, pupa, adult).

Examples

Bugs: Shield bug, aphids, leafhoppers, planthoppers, cicadas, bed bugs are examples of the bugs.

Insects: Butterfly, beetle, bee, ant, fly, termite, grasshopper, true bugs, and louse are examples of insects.

Conclusion

Bugs and insects are two types of small arthropods with three pairs of jointed appendages connected to the abdomen. Both bugs and insects consist of wings. Bugs are a type of insects, having sucking mouthparts called proboscis. But, insects may have other types of mouthparts such as mandible and maxilla for chewing and sponging. The main difference between bugs and insects is the types of mouthparts in each type of arthropods.

Reference:

1. “True Bugs”. ASU – Ask A Biologist, 5 Oct. 2010, Available here.
2. “Insect Identification Key Order Hemiptera: the true bugs.” Know Your Insects, Available here.

Image Courtesy:

1. “Insects in Brockhaus 1937” By scan: Julo – Der Neue Brockhaus (1937), vol. 2 (Public Domain) via Commons Wikimedia
2. “Tachina fly Gonia capitata feeding honey” By Richard Bartz – Own work (CC BY-SA 2.5) via Commons Wikimedia