What’s the Difference Between Bugs and Insects?

What’s the Difference Between Bugs and Insects?

“Bugs” and “insects” are often used as interchangeable words. Whether you call a critter a bug or an insect might depend on how you’re feeling, how casual the conversation is, or purely by chance. It’s common for people to use the word “bug” in casual conversations, while others might refer to them as “insects” to sound more scientific or sophisticated.

But technically speaking, saying that bugs and insects are the same thing and using the terms interchangeably is incorrect. Why? Because bugs and insects aren’t the same – bugs are just one type of insect. 

Know your bugs? Check out this quiz and see how many you can identify.


An insect is defined as “a small arthropod animal that has six legs and generally one or two pairs of wings”. They belong to the arthropod family, consisting of animals with jointed skeletons, segmented bodies, and appendages. They are invertebrates – meaning as they don’t have backbones. As many as 85% of invertebrates are arthropods. There are four arthropod families – arachnids (organisms such as spiders and scorpions), myriapods (organisms with many feet, such as millipedes and centipedes), crustaceans (shrimp, crabs, and lobsters), and insects (such as bees, dragonflies, and ants). 

What differentiates insects from other arthropods? There are three body parts that make insects distinct – the head, thorax, and abdomen. The head is made up of 5-7 segments including the mouthparts, eyes, and antennae, the thorax has three regions and is attached to appendages for movement, and the abdomen has less than 12 segments which may have appendages for reproductive purposes.


True bugs, also known as Hemiptera, are an order of insects. They consist of many different groups, including aphids, planthoppers, cicadas, leafhoppers, and shield bugs. There are approximately 50,000 to 80,000 species of true bugs, ranging in size from 0.04 to 6 inches (or 1 mm to 15 cm). The majority of them eat plants and live in a variety of different habitats. 

The Difference Between Bugs and Insects

To be frank, all bugs are insects – but not all insects are bugs. Bugs are an order of insects, so they’re within that group. There are physical characteristics and habits that differ among bugs and insects, and they typically have different life cycles. 

The Mouth

One major feature that differentiates bugs from other insects is their piercing and sucking mouthparts that are shaped like needles or straws, which true bugs use to suck juices and extract them from plants and assassin bugs use to suck blood from insects. According to the Insect Identification Database, there is a total of 56 species of true bugs in North America. 


Another major difference is that most insects will develop two pairs of wings – four in total. The extra set is designed to protect the fragile underneath layer, also known as “hindwings,” from danger or harm. Bugs, on the other hand, only have one pair of wings and don’t have this extra layer. They do, however, have wings with thicker membranes that gradually thin out towards the ends.

Life Cycle

Most insects go through a four-stage life cycle – egg, larva, pupa, and adult. Laid by the mother on a host plant, an egg can contain just one organism or a few dozen. Next, during the larva stage insects focus on eating and growing as they evolve. After continuing this for about two weeks, the insect will turn into a pupa where it constructs itself as a tight cocoon. During this stage, the cells will start developing adult features, such as mouthparts, legs, and eyes. This stage can last anywhere between a few days and a few years, depending on the species. Once it is complete, the organism will break through its cocoon to evolve into an adult insect. This four-stage cycle is called “complete metamorphosis”. 

Bugs, on the other hand, go through “incomplete metamorphosis” where they only transition through three phases. They start as an egg, go through larva and transition into adults, skipping the pupa stage. 

Liked this article? You might also like: