The scene is a common one; you are sitting outside on a warm summer evening with the porch light glowing. A moth flutters by, catching a glimpse of the light. He begins to float toward the light, seeming unaware of his imminent demise. As he reaches the light, he ceases flying and falls to the ground, ending his time on earth.
This behavior is one we see fairly often. It has even been used to create traps to attract and kill moths and other insects. The question is, why do moths engage in such detrimental behavior? Clearly, the outcome is not a positive one for the moth. Recently, scientists have begun to examine this odd behavior and why it might be occurring. According to one article, there are a few common hypotheses being explored regarding why moths may engage in such seemingly counter-intuitive behavior. Some of the reasons include the moths believing that the light source is actually the moon, the dark space around the light providing a seemingly good hiding place for the moth, or the light actually temporarily blinding and disorienting the moth. While all of these hypotheses seem like reasonable ones, more explorations need to be done in order to determine the true root cause of this behavior.
It should also be noted that not all moths engage in this action. After a recent study exploring moths from different habitats, it has been found that exposure to light pollution plays a role in the tendencies of moths to fly towards light. It appears that moths who live in habitats with high levels of light pollution have learned to refrain from engaging with light sources while moths from darker areas with less light pollution are naive, and hence more likely to fly towards artificial light sources when exposed to them. While it might seem strictly positive that moths are learning not to engage in behavior resulting in their death, there may be larger evolutionary consequences to this change in behavior. If moths evolve to not fly toward light sources, it is worried that animals that prey on them may lose a vital source of food when moths are not flying in the open as often. This is just one effect that this change in behavior could have and who knows what else may follow.
So next time you are enjoying the night sky while sitting on your back deck and you see a moth being lured toward the light, maybe you’ll begin to wonder “what is going through this moths mind right now”. Or maybe you won’t, but I certainly will.
Posted by Jamie Downer (1)