Moths are a diverse group of insects, with over 160,000 known species worldwide, significantly outnumbering butterflies. They are found in nearly every habitat, ranging greatly in size, color, and behavior. While often associated with nighttime and artificial lights, many moth species are active during the day. The common question of whether moths “like” humans stems from their frequent appearance in human environments.
Understanding Moth Attraction
Moth attraction to various stimuli is primarily driven by instinctual biological processes, not an affinity for humans. A key behavior is phototaxis, which describes an organism’s automatic movement toward or away from light. Most nocturnal moths exhibit positive phototaxis. Scientists theorize that moths may use distant light sources, like the moon, for navigation, maintaining a constant angle to the light to fly in a straight line. Artificial lights confuse this navigational system, causing them to orbit or spiral around the light source.
Beyond light, moths rely heavily on chemical signals, particularly pheromones, for communication and reproduction. Female moths release species-specific pheromones to attract males, who detect these scents with highly sensitive antennae, sometimes even from miles away. Males then navigate upwind through turbulent air, following the scent plume to locate a mate. This chemical communication is essential for finding mates and sometimes for other purposes like marking food sources or signaling danger.
Moths and Human Environments
Moths often enter human environments due to the presence of artificial light and readily available resources. Artificial lights, such as porch lights or indoor lamps, disorient nocturnal moths, causing them to flutter around or become trapped near these artificial beacons, leading to their presence inside homes.
Specific moth species are attracted to human spaces because of food sources found within them. Clothes moths, for instance, are drawn to natural fibers containing keratin, a protein found in wool, silk, cashmere, and even hair. They lay their eggs on these materials, and it is the larvae, not the adult moths, that consume the fabrics, causing damage. Similarly, pantry moths are attracted to stored dry goods like grains, flour, and cereals, where they lay eggs and their larvae feed on and contaminate food items. Their presence in homes is thus a search for suitable breeding and feeding grounds, not an interaction with people.
Moth Safety and Behavior
Adult moths are generally harmless to humans, posing no direct threat. The vast majority of adult moths lack mouthparts capable of biting and are not known to sting. They also do not transmit diseases to humans. While their erratic flight around lights can be startling, most species are docile and will try to avoid contact.
Concerns about moths often stem from the activities of their larval stages. Moth larvae, or caterpillars, are responsible for damage to clothing, carpets, and stored food products. Although rare, some moth caterpillars have hairs or spines that can cause skin irritation or allergic reactions upon contact, but this is not a bite or sting from the adult moth.