Week 3: Glowing Bugs

Have you ever stayed up just a little late, looked out your window, and seen fireflies blinking in your backyard? Doesn’t it seem like magic that they can make light inside their bodies? It’s kind of an amazing process! This week, we’ll learn a little about how fireflies get their behinds to blink like that and some other creatures that do the same. Then in our activity, you’ll be able to use your bug net and bug box to catch and closely examine fireflies or any other bugs in your backyard in you might find!

Big Word: Bioluminescence

Scientists use the word “bioluminescence” to describe what fireflies do: light up their bodies from the inside without using fire or electricity. The first part of the word, “bio”, means “life” or “living.” The middle part of the word, “lumin”, comes from the Latin word “lumina”, which means to light up. Finally, the last part of the word, “escence”, means the existence of a thing or phenomenon. So when you break it down, it’s not so hard to figure out! Bioluminescence means the existence of living things that light up!

Is it really fire that lights up a firefly?!

Fireflies don’t really use fire to light up. If they did, they would probably burn up in the process! Fireflies have a special part of their body called a “light organ” where several different chemicals mix together to make a “cold light” that shines just like light from a fire or lightbulb but doesn’t produce heat. 


What’s with all that blinking?

Fireflies put on quite a show for us humans, but that’s not why they blink. Did you know that each different kind of firefly has its own blinking pattern, which helps fireflies of the same species find each other? The blinking also shows animals that might eat them that they won’t make a very good dinner. Apparently many creatures know that animals who are bioluminescent taste yucky!
The video below tells you about a special species of firefly in the southern United States called “synchronous” fireflies. Synchronous is another one of those words with roots from the ancient languages. “Syn” is the Greek root for “same” and “chronos” is the Greek root for “time”. So “synchronous” means happening at the same time! Synchronous fireflies blink in time with one another.


What are some other insects that glow?

There are many other bioluminescent insects besides fireflies, although you won’t find them in your backyard. Glowworms are only found in caves in New Zealand, where they hang from the ceiling on shining strings. The Railroad Worms of South America have two lines of glowing dots down their bodies. Finally, there are 33 species of earthworms, like the wriggly ones you find in your garden, that glow. There is only one in the United States, found in the state of Georgia, which secretes a mucous that glows a bright blue color.

Backyard Activity: Catch a Firefly (or other bug) & sketch it in your field journal

One of the most fun activities of summer is catching fireflies and looking at them in a jar or bug box. In this week’s kit, you received a bug net and a magnifying bug box. When it gets dark, run out into your backyard with your net and try to catch a firefly. Once you’ve got one, put it in your bug box so you can take a close look at its body. What do you see? Sketch a picture or take notes in your field journal from last week! Once you’re done, make sure to let it go. Fireflies need to eat and drink out in the wild to survive.

If it’s too hard to stay up late to catch fireflies, use your bug net to catch other bugs. Swish it through the grass, bushes, or brush, and see what you find in the bottom. Draw pictures of what you find in your field journal!

(Field journal insect sketches by Steve Loya)

Story for Bigger Kids: Fireflies by Roberto Aliaga

Story for Littler Kids: It’s a Firefly Night by Dianne Ochiltree

Craft: Light up Fireflies

This video gives you instructions on how to make a light up firefly with the supplies provided. The only different is that you’ll want to use the gluestick you got in week one to attach the wings, and the eyes have peel off stickers on the back so you don’t have to glue them!

Firefly Coloring Pages