Inside:  Fireflies a a joy to see in the summer. Learn about these intriguing insects – how they produce light and the reasons for their bioluminescence.

Finally, after much thought, planning and a great deal of help from my phenomenally talented sister at Crimson Leaf Studios, my blog Science Alcove has gone live.  Taking some of my design ideas she was able to create a design I love and familiarize me with the WordPress dashboard and the  intricacies of changing code to personalize a template.  I would have been lost without her.  I am incredibly excited to begin this new journey.  I began my writing life on HubPages  and you can still find me publishing at this site.  Many of my posts will link back to articles I’ve posted there.  And now, to discuss the topic of my post…….

Fireflies in the summer are beautiful to watch .  Here in our little corner of Ontario, Canada they seem to be most active during the month of June.  Sitting in our new hot tub on cool summer evenings, has been a treat.  My husband and I have been entertained nightly by the repeated flashing of hundreds of fireflies.  As  a young child, I often caught these beautiful insects in a jar.  I was able to more carefully see their features and discover the source of their beautiful light.  I always set them free soon after so they could continue their signalling.  Fireflies are beetles, most having wings,  belonging to the family Lampyridae. I always wondered how they produced their light and what meaning could be found behind their flashing patterns.  The following is what I have discovered.


Fireflies produce light through bioluminescence.  They have special organs within their abdomen.  In these organs a special chemical reaction occurs.  Organisms producing this light need five things:

  • oxygen,
  • calcium,
  • adenosine triphosphate (ATP) which is the source of energy used by living things,
  • the chemical luciferin
  • the enzyme luciferase (enzymes give a place for the parts of a chemical reaction to find each other; therefore, speeding up that reaction).
What You Need to Know About Fireflies in the summer-What You Need to Know About Fireflies in the summer-

Firefly in Flight

Oxygen enters the body of the firefly through tubes called tracheoles (insects do not have lungs).  In the abdomen of the firefly, the oxygen reacts with the calcium, ATP and luciferin and with the help of the enzyme luciferase voila – the firefly produces light.  Firefly flashes are controlled by the presence or absence of oxygen.  When oxygen is present in the light organ of the abdomen, the firefly produces a flash of light.  When oxygen is absent, no light is produced.  Nitric oxide also appears to play a role creating the high-speed flashes produced by some species of fireflies.  You can read more about this phenomenon in this excellent Scientific American article.  Bioluminescence is a very energy-efficient form of light production.  Very little heat is produced which is obviously very important to the well-being of the firefly.  The light produced by these insects ranges from a pale yellow to red-green color (between 510 and 670 nanometers).


Fireflies produce light for a number of reasons.

  1. In order to protect themselves from predators, fireflies produce bad-tasting chemicals.  Larva will light up to warn predators that they taste bad.
  2. Adult fireflies of each species have a unique flash pattern.  As well, males and females within a species have a unique flash pattern.  Adults use these flash patterns to find members of their species and to find members of the opposite sex during mating season.
  3. Female fireflies seem to choose their mates based on faster flash rates and brighter flashes.

“How do fireflies light up”?  19 January 2001. <> 05 July 2014.

“How and why do fireflies light up?”  5 September 2005.  Scientific American. 5 July 2014.

“Fireflies (Lightning Bugs)”.  National Geographic. 5 July 2014.

What You Need to Know About Fireflies in the summer-What You Need to Know About Fireflies in the summer-


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