Biodiversity
Brain
EntomOLogy
Genetics
Marine BiOLogy
MicrobiOLogy
PaleontOLogy
ZoOLogy
AnthropOLogy
ArchaeOLogy
Astronomy
Climate Change
Earth
Physics
Water
BIG IDEAS
What is EntomOLogy?
Entomology is the study of insects. They are the largest and most diverse group of animals on Earth. Insects existed hundreds of millions of years before the first dinosaurs. And millions of insect species are alive today!
Insects are a group of animals that share certain characteristics. All full-grown insects have six legs, three body segments, and two antennae. That’s how scientists know they’re insects.
Insects can look very different, but they all have the same kinds and numbers of body parts.
Are these all insects?
Tip: Count their body parts!
What are NOT insects? Spiders have eight legs, so they aren’t insects. Neither are centipedes, with a whole lot of segments and one pair of legs on each segment. Ticks, scorpions, shrimps, and crabs might look like insects, but they’re not. Just count their legs, body segments, and antennae.
Insects are amazingly diverse. They live all over our planet, everywhere except in the ocean. Some, like butterflies and grasshoppers, eat plants. Others, like dragonflies and praying mantises, eat other animals, including other insects. Some live on land. Some live in lakes, streams, and puddles. Some can fly, some can burrow, and some can only walk.
Scientists organize insects into groups called orders. There are 26 of them. Here are eight major groups to get to know. Check out examples of each below!
Orthoptera
(crickets, grasshoppers, katydids)
This is a fossil of Meganeura, a giant relative of today’s dragonflies. They lived about 300 million years ago and had wingspans of over 2 feet wide. That’s as big as some birds! Back then, Earth’s atmosphere was richer in oxygen than today. This helped insects grow much bigger than they do now.
Insects have been around for hundreds of millions of years. Some groups, like giant flying insects, went extinct long ago, but smaller related insects have evolved over time. In fact, if you put a modern field guide in your backpack and used a time machine to go back 200 million years, you would be able to identify all the major groups of insects you saw.
There are millions of insect species living today. There are more known species of insects than of any other kind of animal! And scientists think there might be 10 million more insect species waiting to be described.
Not only are there lots of different kinds of insects, but there are also a huge number of individual insects. Scientists think there are something like a quintillion insects alive today! That’s 10 followed by 18 zeroes:
10,000,000,000,000,000,000
Insects have many different important roles on our planet. That’s because there are so many insects and so many kinds. It’s also because they have been around so long. And it’s because they live in so many different habitats.
In this park ecosystem, insects are busy doing different jobs. Some help plants grow, some clean up, and some become food for other animals!
Decomposers: Insects help decompose dead plants and animals, breaking them down into useful nutrients. They mix up the soil, helping plants grow.
Pollinators: They carry pollen from flower to flower, helping plants produce seeds and fruit. Without insects, we would have a hard time growing crops. Not all pollinators are as well known for pollinating as bees and butterflies. Flies, beetles, and mosquitoes pollinate plants too.
Prey: All sorts of animals eat insects, from birds to frogs to bats, and also humans! Some insects eat other insects.
Predators: Dragonflies can help keep us healthy by eating mosquitoes that carry diseases.
Cleaners: Some insects filter nutrients and contaminants out of water. For example, stoneflies have little gills that look like hairy armpits. They use them to breathe and also to get nutrients.
There are a lot fewer cabbage white butterflies today than in the year 2000. More than half of them are gone!
For a long time, scientists have suspected that insect numbers are declining, but it wasn’t until recently that they counted them scientifically. All around the world, the majority of insects are in trouble. Between 2000 to 2020, butterflies in the United States declined by 22 percent. For every five butterflies in 2000, there are now less than four today. And that’s just the average. Some groups had it even worse. Cabbage white butterflies, for example, declined by over 50 percent. That means there are fewer than half as many now as there were in 2000. Some species declined by 99 percent and are now on the verge of extinction.
Extreme Weather: Because of climate change, storms and droughts are becoming more common and more severe. Some areas are drying out. Others are becoming too wet or too hot. Those extremes make it hard for insects to live there.
Loss of Habitat: People are taking over wild land to use for farms, cities, and suburbs, destroying insect habitats.
Light and Noise: Bright lights of homes and cities can confuse night-flying insects and make it hard for them to find their way. And loud noise can make it hard for insects to communicate by making sounds.
Insecticides: Farmers and gardeners use insecticides to poison insects that eat crops. We use them on unwanted household visitors like mosquitoes and cockroaches, too. Those chemicals harm many other insects too, not just the ones we’re trying to kill.
There’s lots you can do to help!
What would YOU like to do to help insects?
Grow Plants That Insects Like
Different insects eat and live on different plants. You can grow their favorite plants in your own garden, at your school, in a community garden, or even in a window box.
Turn Off Bright Lights at Night
Bright lights confuse fireflies
and other night-flying insects. After dark, if you have outdoor lights with a bluish tone, you can switch to lights with a yellowish tone instead. Even better, you can turn off outdoor lights. That’s especially important in summer.
Use Gentler Insecticide
Try using soapy water instead of strong pesticide at home. It removes pests without harmful chemicals. This keeps helpful insects safe and protects your plants and the environment.
Discover Insects in Your Neighborhood
Find out how to identify and name the insects that live around you. That way, if a new invasive species
shows up, you’ll spot it.
Get Others to Help!
Invite your family, friends, school, and local officials to do all those things too!
Image Credits:
illustrations of moth, grasshopper, cucumber beetle, monarch caterpillar, green bean stick bug, dragonfly, blue longhorn beetle, and wasp, Stephanie Fotiadis/© AMNH; ant illustration, Shutterstock; grasshopper, Alex Hyde/Nature Picture Library/Alamy; bee, Shutterstock; jumping spider, Adam Fletcher/Biosphoto/Science Source; ladybug, Francisco Welter-Schultes; staghorn beetle, Patrick Coin/CC BY-NC-SA 2.0; firefly, Terry Priest/CC BY-SA 2.0; domino cockroach, Shyamal/CC BY-SA 3.0; orchid mantis, Chien Lee/Minden Pictures; termite, Scott Bauer/USDA; green bottle fly, Skyler Ewing/Pexels; mosquito, Kim Taylor/Minden Pictures; robber fly, Zakidot/CC BY-SA 4.0; aphid, Mika Andrianoelison/CC BY-NC-SA 2.0; emerald cicada, Andreas Kay/CC BY-NC-SA 2.0; milkweed bug, Don Johnston/AGE Fotostock; leafcutter ant, Kim Taylor/Nature Picture Library/Alamy; sweat bee, Judy Gallagher/CC BY 2.0; mud dauber wasp, Shyamal/CC BY-SA 3.0; zebra butterfly, Zoonar/Jearu/AGE Fotostock; monarch, Daphne Kinzler/FLPA/AGE Fotostock; Polyphemus moth, MYN-Javier Aznar/Nature Picture Library/Alamy; Jerusalem cricket, Tim Ereneta/CC BY-NC 2.0; southern lubber grasshopper, Patti Murray/Animals Animals/AGE Fotostock; katydid, Tammy Wolfe/Alamy; leaf insect, Steve Hopkin/Ardea/AGE Fotostock; Vietnamese stick insect, Drägüs/CC BY-NC 2.0; Gray's Haaniella, Drägüs/CC BY-NC 2.0; Meganeura, Tylwyth Eldar/CC BY-SA 4.0; cabbage white butterfly, John Strung/CC BY-NC-SA 2.0.