Termites are social insects often seen gathering around exterior lights or window panes. This common sight, usually occurring during specific seasons, is a biological phenomenon rooted in the insect’s life cycle. The flying termites, known as alates, are reproductive individuals participating in a mass dispersal event aimed at establishing new colonies. Their attraction to light is a misdirected remnant of a natural navigational strategy.
Understanding Positive Phototaxis
The behavior of flying termites moving toward a light source is known as positive phototaxis. This inherent tendency to orient toward light is a navigational tool that evolved to serve a specific purpose. Termite alates historically used distant light sources, such as the sun or moon, to maintain a straight flight path during their dispersal journey.
Insects maintain a stable flight direction by orienting themselves at a constant angle relative to a distant, celestial light source. When they encounter an intense, stationary, and close artificial light, this natural guidance system becomes confused. The alate continuously adjusts its flight angle in relation to the nearby light, resulting in the insect flying in circles or spirals around the bulb.
This disorientation causes the characteristic clustering of insects near porch lights or windows. Different species, such as the nocturnal Formosan termite, are particularly attracted to the short-wavelength light emitted by many artificial bulbs.
The Timing and Purpose of Termite Swarming
This light-attraction behavior is only exhibited by the winged reproductive caste, which is produced during swarming. Swarming is a synchronized reproductive flight where thousands of alates leave their established colony to disperse, mate, and found new colonies.
The timing of a termite swarm is triggered by environmental cues that signal ideal conditions for survival outside the nest. These triggers include warm temperatures, high humidity, and recent rainfall that moistens the soil. The moisture ensures that the alates do not quickly desiccate and that the soil is soft enough for a newly paired couple to burrow. Swarming seasons vary by species; many subterranean termites swarm in the spring during the day, while species like the Formosan termite swarm during warm, humid evenings.
Colony Establishment: The End Goal of Flying Termites
The flight toward the light source is the first phase of the reproductive process for the alates. Once they land, males and females seek a mate, and pairs shed their wings at a pre-formed suture line. Piles of discarded wings near a light source or window are a tell-tale sign that a swarm has occurred.
After shedding their wings, the male and female engage in “tandem running,” where the male closely follows the female. The female leads the pair on a search for a suitable nesting site, which must provide wood and adequate moisture. Once a location is found, the pair burrows into the soil or wood to establish the nuptial chamber, becoming the king and queen of a new colony. Only a small percentage of swarmers will successfully found a new colony.
What to Do When Termites Swarm Near Light Sources
Observing a swarm of winged insects near exterior lights requires determining if they are termites or flying ants. Termite alates have straight antennae, a broad, uniform waist, and four wings of equal length. Flying ants, conversely, have bent antennae, a pinched waist, and two pairs of wings where the front pair is noticeably larger than the hind pair.
If the insects are identified as termites, action should focus on limiting their entry. Turning off exterior lights and closing blinds will reduce the attraction and prevent more alates from congregating near the structure. Swarmers that have entered the home can be removed by vacuuming them up, as they will die quickly if they cannot reach the soil. Seeing a swarm indoors suggests a mature colony is already established within the structure and requires a professional inspection.