What is the Difference Between a Bug and a Beetle

February 2023 · 5 minute read

The main difference between a bug and a beetle is that a bug belongs to the order Hemiptera whereas a beetle belongs to the order Coleoptera. Furthermore, bugs are mostly plant-feeders that take a liquid diet while beetles eat a wide range of plant and animal materials. Therefore, bugs have needle-like mouthparts while beetles have chewing mouthparts. Moreover, the wings of bugs are either membranous or partially-thickened while the forewings of beetles serve as a hard, leathery covering called elytra and the hindwings are membranous.

Bug and beetle are two groups of insects that belong to two different orders. Around 75000 species of bugs and 400000 species of beetles have been identified so far.

Key Areas Covered

1. Bug
     – Definition, Characteristics, Behavior
2. Beetle
     – Definition, Characteristics, Behavior
3. What are the Similarities Between Bug and Beetle
     – Outline of Common Features
4. What is the Difference Between a Bug and a Beetle
     – Comparison of Key Differences

Key Terms

Beetle, Bug, Diet, Forewings, Lifecycle, Metamorphosis, Mouthparts, Order

Difference Between a Bug and a Beetle - Comparison Summary

Bug – Definition, Characteristics, Behavior

Bugs are a group of insects classified under the order Hemiptera. The size of bugs varies from 1 mm- 15 cm. One of the main features of bugs is the presence of sucking mouthparts. However, only heteropterans are considered as ‘True bugs’. The sucking and the piercing mouthparts allow bugs to extract plant sap and nectar. Therefore, most bugs are plant feeders. But, some of them are parasitic and others are predators that prey on other insects or small invertebrates.

What is the Difference Between a Bug and a Beetle

Figure 1: Wheel Bug

Furthermore, both wings of the bugs are membranous. However, their forewings are thick at the base of the wing. Also, another significant feature of bugs is their life cycle. They undergo incomplete metamorphosis. That means; the juveniles of bugs are small and morphologically similar to the adult.  

Beetle – Definition, Characteristics, Behavior

Beetles are another group of insects classified under the order Coleoptera. More importantly, they are the largest order, containing 40% of the all described insects and 25% of all animal forms. Around 400000 species of beetles have been identified so far. Also, weevils are the largest family of beetles. One of the significant anatomical features of beetles is the presence of chewing mouthparts. Therefore, most plant-feeding beetles damage crops while animal-feeding beetles eat aphids, scale insects, thrips, etc.

Difference Between a Bug and a Beetle

Figure 2: Beetles

Moreover, the forewings of beetles are modified structures called elytra, which are hard leathery structures, covering the hindwings at rest. However, their hindwings are membranous. Moreover, beetles undergo complete metamorphosis. Therefore, the larval stage of beetles is called grubs due to their hardened head, pupating into the adult stage.

Similarities Between Bug and Beetle

Difference Between a Bug and a Beetle

Definition

A bug refers to any of an order (Hemiptera and especially its suborder Heteroptera) of insects (such as an assassin bug or chinch bug) that have sucking mouthparts, forewings thickened at the base, and incomplete metamorphosis and are often economic pests while a beetle refers to any of an order (Coleoptera) of insects having four wings of which the outer pair are modified into stiff elytra that protect the inner pair when at rest. Thus, this explains the fundamental difference between a bug and a beetle.

Order

The main difference between a bug and a beetle is that a bug belongs to the order Hemiptera while a beetle belongs to the order Coleoptera.

Number of Species

Around 75000 species of bugs have been identified so far while around 400000 species of beetles have been identified.

Diet

Most bugs are plant-feeders while beetles eat both plant and animal materials. Hence, this is another difference between a bug and a beetle.

Mouthparts

Also, a notable difference between a bug and a beetle is their mouthparts. Bugs have a needle-like, piercing stylet while beetles have chewing mouthparts.

Antennas

Furthermore, the antennas of bugs are composed of 4-5 segments while the antennas of beetles are composed of around 11 segments.

Wings

Moreover, bugs have membranous wings and their forewings are thickened at the base while the forewings of beetles are modified to elytra, a hard and leathery covering while their hindwings are membranous.

Lifecycle

Besides, one other difference between a bug and a beetle is that while bugs undergo incomplete metamorphosis, beetles undergo complete metamorphosis.

Examples

Some examples of bugs are cicadas, aphids, planthoppers, leafhoppers, and shield bugs while some examples of beetles are ladybird beetle, leaf beetle, ground beetle, scarabs, longhorn beetle, weevil, stag beetle, and Firefly.

Conclusion

Bugs are insects belonging to the order Hemiptera. Most of them are plant-feeders with needle-like mouthparts. Generally, their wings are membranous, but the base of the forewing can be thick. In comparison, beetles are another order of insects classified under the order Coleoptera. They eat both plant and animal materials. Hence, they have chewing mouthparts. The forewings of beetles are hard and leathery. Therefore, the main difference between a bug and a beetle is their anatomical features and feeding behavior.

References:

1. “Hemiptera: Bugs, Aphids and Cicadas.” CSIRO, Available Here.
2. “Coleoptera: Beetles and Weevils.” CSIRO, Available Here

Image Courtesy:

1. “Wheel Bug in Missouri” By USFWS Midwest Region (CC BY 2.0) via Flickr
2. “Coleoptera collage” By Bugboy52.40 – Own work (from User:Fir0002 images) (CC BY-SA 3.0) via Commons Wikimedia  

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