Skip to main content

#57: Fireflies

Litinsects #57: Fireflies

© Radim Schreiber

You may know them as fireflies, lightning bugs, or glowworms depending on where you grew up…  these glowing bugs are actually neither flies, nor bugs, nor worms but beetles. They are a special group known for their BIOLUMINESCENCE. So how does that work?

Bioluminescence is light produced by an organism through a chemical reaction. In some animals light is produced by bacterial symbionts, in others the light is produced by the organisms themselves, as is the case with fireflies. (Side note: this is different than biofluorescence, which is the absorption and re-emission of certain wavelengths but it doesn’t involve a chemical reaction.)

Fireflies have a LIGHT ORGAN in their lower abdomen in which a special reaction takes place; it produces light but no heat (thus often called “cold light”). A compound called LUCIFERIN, coming from the Latin word for „light-bearing“ (also the same etymology for the name Lucifer) is contained in these light organs. Light is produced when luciferin combines with oxygen, calcium, and ATP (a molecule that provides energy in cells) in the presence of an enzyme called luciferase. The resulting light may range from yellow to green and even to pale reddish.

-Each firefly species has its OWN PATTERN of light flashes to attract mates. In most species both sexes glow although sometimes only one sex does. Usually males flash to advertise themselves to females, who respond with flashes to show their location. The females of certain species use this to their advantage by mimicking the flash signals of another species’ females to attract males to prey upon!

-Some species have LARVIFORM FEMALES, which are wingless adult females that closely resemble larvae in appearance. These females stay on the ground while males fly around flashing

-Though it seems counter-intuitive there are in fact fireflies that are not bioluminescent and some that flash but are active during the day. These species usually rely more on PHEROMONES to attract mates (more on those to come soon!)

-Flashing can even deter predators! Some fireflies produce defensive steroids that make them taste very bad, so predators learn to associate the flashing with a bad-tasting meal and leave them alone

-Fireflies are very sensitive to artificial light, since they depend on their light signals to reproduce. They are therefore good BIOINDICATORS of light pollution

Labels:

Comments

Post a Comment

Popular posts from this blog

#8: Butterfly Wings

Litinsects #8: Butterfly Wings Have you ever heard that you shouldn’t touch a butterfly’s wings or it will die? Well why is that...? Who remembers what I explained yesterday about Latin names? Butterflies and moths belong to the group LEPIDOPTERA, from the Greek words lepis for scale and pteron for wing. You probably guessed it already: butterfly wings are covered in SCALES! (Anyone starting to see a pattern with the names here? 😉 ) Butterfly scales are actually modified, flattened SETAE (aka hairs) that either partially or entirely cover the wings of most species. Some look like roof tiles, like on this here monarch, while some look more thread-like Scales protect and insulate the insect, but underneath the wing is actually transparent! Some species, like the GLASSWING BUTTERFLY, lack scales and have totally amazing see-through wings! Scales are responsible for the coloration of butterfly wings in one of two ways. First of all, scales contain...
Post a Comment
Read more

#58: Tardigrades

Litinsects #58: Tardigrades Anyone recognize these weird-looking little guys? They are actually not insects, as a matter of fact they are not even arthropods but they are cool enough to deserve a post. These are TARDIGRADES, also known as water bears or moss piglets. They are best known for their bizarre abilities to survive some of the most extreme conditions imaginable... © Science Faction Images -As always, the name’s etymology describes them a bit. It comes from the Latin “tardus” meaning “slow” and “gradior” for “step/walk”. Their common name comes from the fact that their walk looks a bit like a bear’s -Tardigrades are a PHYLUM of animals consisting of around 1,300 species. (Side note: the TAXONOMIC LEVEL of a group has nothing to do with how many species it contains. For example phylum Arthropoda, a taxonomically equivalent category consists of around 1 million described species and possibly millions more not yet described!). -These animals are all microscopic, ranging in ...
Post a Comment
Read more

#60: Cockroaches

Litinsects #60: Cockroaches Cockroaches belong to the order BLATTODEA, which is derived from the Greek word “blatta” meaning cockroach. Did you know that the Blattodea contains cockroaches AND termites? That’s right; termites are actually considered a specialized group of cockroaches! They used to be classified in an entirely different order of insects but recent genetic studies found a closer relation to cockroaches than previously thought. -Roaches are characterized by their broad, flat bodies. They have long antennae and generalized chewing mouthparts. In contrast to many other insects, which have 3, cockroaches have only 2 ocelli (or simple eyes) -Most people consider roaches to be disgusting, disease-spreading pests. But of 4,500 species, only 30 live in human habitats and are considered pests -The common name is derived from the Spanish word for the insect, “cucaracha” -Cockroaches can be found in a wide variety of habitats around the world. Many live in the tropics but...
Post a Comment
Read more