Lesser Houseflies (fannia-canicularis)
Appearance
Adult Body length about 5-6mm long. Slender. Yellow spots can be noticed on the abdomen.
The adult colour is blackish-gray with 3 distinct black dorsal longitudinal thoracic stripes. Also the fourth longitudinal wing vein is straight (unlike the Housefly).
Habits
How to identify lesser houseflies indoors: The most reliable way to distinguish a lesser housefly from a common housefly is its characteristic indoor flight pattern. Lesser houseflies fly in short straight lines of 20-30cm, turn abruptly at an angle, then continue in another straight line — repeating this geometric pattern continuously. They appear to be “patrolling” a fixed area rather than flying randomly. This behaviour is most commonly seen in the middle of rooms, often on sunny days when a single shaft of light illuminates the space. Common houseflies do not behave this way.
Threats
The lesser housefly ability to spread diseases amongst humans seems to be less than that of the Common House Fly, although this may be more due to its more restricted contact with humans rather than any innate reason.
Generally the habits of the lesser housefly rarely bring it into contact with human food and therefore it is not considered to be such an important vector of diseases.
Prevention
- Finding the breeding site is always crucial but is more difficult with this species. It may be some distance away from the problem site.
- Larvae feed on the decaying vegetation or manure in which they were laid.
- Pupation takes place in the drier areas of the breeding site.
- Organic material should not be left where it might attract flies.
- Remove trash regularly and use well-sealing garbage receptacles.
- Use Fly screens on doors and windows to prevent lesser housefly entry.
Why Are Lesser Houseflies Appearing Indoors?
Unlike common houseflies which breed in exposed food waste, lesser houseflies breed in organic material outdoors — compost heaps, manure, decaying garden vegetation, and occasionally bird or rodent nests. Adult flies enter buildings through open doors and windows in search of warmth and shade.
The key difference from common houseflies: lesser houseflies indoors are almost never breeding there. They are resting adults that have come in from outside. This means the breeding source is typically in the garden rather than inside the property, and removing or relocating compost heaps, covering bin areas, and clearing garden debris will reduce the number of adults entering the building.
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DIY Lesser Housefly Treatments - Get Rid of Lesser Houseflies
Want to get rid of lesser houseflies by yourself?
Click on the links below for more details or to buy DIY lesser houseflies killing products online
Note: We do not recommend using Electric Fly Killer units against houseflies, as these are not attracted to UV light.
Contact Owl Pest Control
Do you have a Lesser Housefly problem and need to talk to an expert?
Contact Owl Pest Control today!
Unit 19, Tallaght Business Centre, Whitestown Road, Tallaght, Dublin 24. D24 TD42
