Valentine’s Day: a holiday dedicated to the celebration of love between people, a day where romantics shower their significant other with gifts of flowers and chocolate, or take them out to a fancy restaurant for a delicious meal. Then there’s people like me, who spend Valentine’s Day hastily photoshopping celebrities or video game characters on to pink backgrounds before adding a bad pun and sending them to my friends over Facebook. In celebration, I’m going to talk about Pokemon’s official lovebugs, Volbeat and Illumise.
Volbeat and Illumise are based off fireflies, a family of beetles (not flies) most known for their ability to flash a specialized organ found at the end of their abdomen. Fireflies flash their bioluminescent rump by mixing oxygen with an enzyme called luciferase, which breaks down luciferin and releases light. This flashing has a few uses, but the most common one is finding a mate. Males flash their rear ends in set rhythmic patterns that differ between species. Females of the same species are able to recognize these patterns, and will respond to a potential mate with a flash of their own.
Interestingly, the male fireflies greatly outnumber the females, meaning that most of the males flashing their behinds are never going to get a chance to mate. Females are incredibly selective about which males they respond to, choosing only to respond to males that either flash faster or longer than other males, depending on the species. In the Pokemon world, male Volbeat take this rhythmic flashing a few steps above and beyond fireflies, working together with other Volbeat to create geometric patterns in the sky as directed by female Illumise.
To direct their Volbeat suitors, Illumise use pheromones, specialized chemicals that are used for communicating. Pheromones can be found in a wide range of animals, and are typically used to communicate through an animal’s sense of smell. One well-known example of animals that use pheromones are dogs, which urinate on objects such as trees or fire hydrants to mark their territory. Other animals, such as ants, will use pheromones to mark trails for other members of their colony to follow to food sources. In the case of Illumise, the pheromones are being used to attract potential mates, a common tactic for many insects, including some fireflies.
While fireflies may not make as intricate patterns in the sky as their Pokemon counterparts, firefly bioluminescence is pretty spectacular. Fireflies are very efficient when it comes to producing light, with 96% of the energy produced by the breakdown of luciferin being emitted as light. For comparison, fluorescent lights are about 40% efficient, with the rest of the energy being wasted as heat.
One of the major factors that allow fireflies to be so efficient is the structure of the exoskeleton covering their light-emitting organ. Light moves at different speeds depending on what it is travelling through, which causes the light to bend slightly. This property is called refraction, and is the reason the sky is blue, rainbows exist, and glasses work. For fireflies, however, refraction is a problem, as light passing through the abdomen of the firefly can bend and become trapped inside the exoskeleton (and ultimately converted to heat) rather than passing through and reaching a potential mate. To counter this, fireflies have evolved complex microscopic structures that reduce the effect of refraction, ensuring that the maximum amount of light possible can escape their bodies. Scientists are even replicating the structures in OLEDs, resulting in a 55% increase in thee light’s efficiency.
While I typically equate fireflies with warm summer evenings, watching them flicker across a field after the sun goes down, I find that Volbeat and Illumise are better fit into Valentine’s Day than summer. Maybe it’s because of their Valentine themed colors, maybe it’s because they were intended to be a pair (they were introduced at the same time the idea of double-battles were added), or maybe it’s because their main goal is to find each other and light up the night together. Have a good Valentine’s Day.
There are some species of fireflies where the females will respond to the flashes of males from other species so they can capture and devour them. They do this in order to steal defensive chemicals known as lucibufagins, which they are unable to produce themselves. These chemicals are useful for repelling potential predators such as spiders and birds, as well as protecting their eggs. This behavior isn’t found in Volbeat or Illumise, but it’s too interesting to leave out of the post.