Why do fireflies give off light?

Question

Help us!

Answer 1

*
******
*********************
Why do Fireflies Flash?

Fireflies rely on precise control of flash timing for two purposes: finding mates, and luring prey.

In the group Photinus, flashing represents a visible courtship signal. Within each species, males and females identify members of the opposite sex based on flash timing.

In the group Photuris, flashing serves an additional purpose. Female Photuris fireflies are highly specialized predators that can facultatively imitate the flash signal given by other species' females. Using this false signal, these predatory females are able to lure in unsuspecting Photinus males, then eat them (see the photo at the top of this page).

On the right are shown the flashes and flight paths of different species as they would appear in a time-lapse photograph (From: Lloyd, J. E. (1966). Univ. of Michigan Museum of Zoology, Misc. Pub. 130, 1-93)

**
************************
**
Nitric oxide (NO) is a soluble, highly reactive gas formed by natural chemical and physical reactions in the atmosphere. It is also produced by certain animal and plant cells from the amino acid, L-arginine. Because it is so small and diffusible NO passes through cell membranes and is often used as a biological signal.

In mammals NO helps to maintain blood pressure by dilating blood vessels, assists the immune system in killing invaders, and is a major factor in the control of penile erection (Viagra® works by blocking an enzyme in the NO/cGMP pathway). In the brain, NO plays a role in development, neuron to neuron signaling, and probably contributes to the formation of memories.

Most non-pathological functions of NO are mediated by activation of an enzyme, guanylyl cyclase, or by nitrosylation of proteins. However, NO can also inhibit oxygen consumption by mitochondria and it is this action that is exploited in producing firefly light flashes.

The Firefly lantern is located on the ventral abdominal surface (stippled area) beneath translucent cuticle. It is innervated by octopaminergic neurons in the posterior ganglia of the nerve cord. Bursts of action potentials in these neurons control the normal flash pattern. In each light-producing unit, photocytes are arranged radially into a rosette pattern around a central cylindrical core. The core includes a main air-containing trachea that originates dorsally and divides several times into fine tracheoles that project between the photocytes at several dorsal-ventral levels. Each trachea is ringed by tracheolar cells and tracheolar end cells. The luciferin-luciferase light producing reactions are confined to peroxisomes located centrally in photocytes. The photocyte mitochondria are found in the peripheral cytoplasm, concentrated especially at locations proximal to the trachea and tracheoles

Luciferin is activated by luciferase in an ATP-dependent step to form a luciferin-adenylyl intermediate; when oxygen is present this intermediate is rapidly converted to a peroxyluciferin product that decays to oxyluciferin with the emission of photons.
When fireflies are placed into NO they begin to flash very rapidly and the lantern glows continuously. This response requires oxygen. Glowing is also evoked by applying the transmitter octopamine to the exposed lantern. Octopamine glow is inhibited by NO scavengers such as CPTIO.
********************
********
****
***
**
*

.

Answer 2

Fireflies produce certain organic compounds generally known as luciferin. In the presence of the enzyme, luciferase and oxygen, it will give off bioluminescent light.

Answer 3

Why? To attract mates.

How?

Their cells contain a chemical called luciferin and make an enzyme called luciferase. To make light, the luciferin combines with oxygen to form an inactive molecule called oxyluciferin. The luciferase speeds up the reaction, which occurs in two steps:

The luciferin combines with adenosine triphosphate (ATP), which is found in all cells, to form luciferyl adenylate and pyrophosphate (PPi) on the surface of the luciferase enzyme. The luciferyl adenylate remains bound to the enzyme:

luciferin + ATP -------------> luciferyl adenylate + PPi

The luciferyl adenylate combines with oxygen to form oxyluciferin and adenosine monophosphate (AMP). Light is given off and the oxyluciferin and AMP are released from the enzyme's surface:

luciferyl adenylate + O2 -------------> oxyluciferin +AMP + light

Answer 4

they give off light to attract a mate

Answer 5

Not sure but glowworms glow to attract males.

Answer 6

they are looking for a mate

Answer 7

... because they feel like it?

Answer 8

think its bacteria in its butt that does it.

Answer 9

there on fire