Fireflies light the night for love

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By Jeneen Wiche

Likely as a child, you, too, collected fireflies in a jar and took them to bed to light up your room on a warm summer night.  I remember getting my parents to puncture the lid of a mason jar so the magical insects could breathe.  Well, it turns out that all that light flashing wasn’t meant for our entertainment, but rather about entertaining love.
Researchers at Tufts University and Brigham and Women’s Hospital have been observing the flashes of fireflies for a decade of summers and what they have uncovered may surprise you.  The bioluminescence of the male firefly is his way of telling the female firefly that he is a worthy lover.
Fireflies, which are actually beetles, spend their entire lives looking for love. Female fireflies are rather promiscuous, mating with dozens of males in their lifetime and simultaneously carrying eggs from many different fathers. The female can control how many eggs are fertilized by her mates and she proves to be quite choosy, looking to a male’s flash pattern as an indicator of virility.  
There are hundreds of different firefly species worldwide and several out in the yard on any given night.  The flash pattern also helps the species locate their own in a field of flashing singles looking for love.  
In 2003, Sara Lewis, an evolutionary biologist at Tufts University, and her graduate student Christopher Cratsley, set out to understand the meaning of the firefly’s flash and what they found was a direct link between flash patterns and the “nutritional gift” the male gave to the female.
Lewis explains that the “nutritional gift” is communicated in a male firefly’s flash code.  Far from random, these flash codes tell females that the male is of her species, is ready for her and has a “nuptial gift” that contains sperm and nutrition.  This is where the code is important because the nutritional component is crucial for the eggs to develop because the firefly eats nothing in its adult stage.  
According to Lewis’ research, the length of a male’s flash, or should I say duration of the flash, is a predictor of the quality of the nuptial gift. More sperm and more nutrition mean more babies.
The science of it all is interesting and important as well.  Bioluminescence has been understood for a long time now, but new light has been shed on the role nitric oxide plays.  In humans, nitric oxide acts as a messenger in the body, controlling the flow of blood and aiding in memory and learning. In fireflies it is the key component in controlling the flash of the abdominal lantern, it acts as the on-off switch.
In the lab, researchers were able to determine that, simply put (sort of), the abdominal lantern is dark and at rest while the mitochondria consumes the oxygen that is present in the cells (apparently mitochondria eat up oxygen quickly).  When nitric oxide is produced, it basically steals the oxygen from the mitochondria and the lights go on.  It all happens in a split second and the beetle’s nervous system keeps the flash code going all night long.
Whether it’s a firefly’s flash or a peacock’s feathers, it seems that humans are not the only ones that try to attract a mate by being a bit flashy.