Insect in the Toilet with an 'Instant Movement' Sensation

The small insect commonly found in toilets that gives the sensation of 'instant movement' is the moth fly, also known as Psychodidae, drain fly, or sewage fly.

Appearance Characteristics

Moth fly larvae are small, typically measuring between 2 - 5 millimeters in length. Their entire bodies are grayish-black and covered with fine hairs, which not only add to their unique appearance but may also carry tiny particles during their activities. Their wings are oval-shaped, and they do not fly very fast. However, they often engage in short-distance hopping flights near floor drains, sinks, and washbasins. This mode of short-distance, rapid movement, combined with their small size, can easily create the illusion of 'instant movement'.

Living Environment

Moth flies prefer damp environments with decaying organic matter. In toilets, places like sink overflow holes, floor drains, and shower drains are common haunts. These areas usually have standing water and accumulate organic debris such as hair, skin flakes, and food scraps, providing a rich food source and a suitable living environment for the larvae of moth flies. The larvae live in sewage and organic debris, feeding on these organic materials for growth and development. Adult moth flies, on the other hand, move around in relatively open spaces but still cannot do without damp environments with decaying organic matter.

Potential Hazards

The bodies of adult moth flies are covered with fine hairs that may come into contact with and mechanically carry various microorganisms. When they move around in spaces like toilets, they have the potential to transfer these microorganisms to the surfaces of surrounding objects, such as towels, toothbrushes, and toiletries, posing a risk of contaminating these item surfaces and thus presenting a certain potential threat to human health. Therefore, if moth flies are found in the toilet, timely measures should be taken for cleaning and prevention to maintain the cleanliness and dryness of the toilet and reduce the breeding environment for moth flies.