Tuesday, June 30, 2009

talking to fireflies

in an engaging new york times piece called "blink twice if you like me" evolutionary ecologist Dr. Lewis shares her research on the beautiful light show mating ritual of fireflies and effects of darwin's sexual selection.

the natural firework show we see at night is actually male fireflies fly through the air emitting flash patterns for females looking on in the grass below. in a field with hundreds of male fireflies, it's not uncommon to find only two or three females looking for a mate (like the bachelorette^100). females observe the light show, and select mates based on the number of flashes emitted, and the pauses between each flash. some female species respond by emitting a flash at precise intervals between the male flashes.

“Most people don’t realize there’s this call and response going on," dr. lewis explains as she flashes a photinus greeni penlight back at the males. "it's very, very easy to talk to fireflies."

eager to explore how female fireflies were picking their mates, she created a computer-controlled light system in her lab that mimiced firefly flashes and observed which patterns the females responded to.

she also discovered the existence of these so-called "nuptial gifts" males carry in the abdomen filled with beautiful coiled proteins injected with their sperm (see photo below). the nuptial gifts can double the amount of eggs a female can lay in her lifetime, and dr. lewis deduced that some female species pick their mates based on their light patterns that are directly correlated to the size of their protein/sperm packages.


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