There are dozens of species of flying insects that are common to Ireland. The most common is the Housefly (musca domestica) but we also have Bluebottle (calliphora erythrocephala), Cluster Fly (pollenia rudis) and a family of flies also known as filter flies and which include Beerfly, (drosophila melanogaster) Sewer/Drain Fly (psychoda alternata) and Fruit Fly (drosophila spp.) Biological characteristics aside, the one thing they all have in common is that there has to be a reason for their presence.
Houseflies are attracted to any foodstuff and tend to be at their most prolific in summer time. The first defence for houseflies from the home or business premises is the fitting of insect screens and doors to all window opes and doors. These screens only have a very slight impact on ventilation and lighting but the benefits are a complete fly free environment. Electric Fly Killing Units can be used but are less desirable in a private residence than they are in a commercial premises.
Bluebottles are not normally present unless there is rotting matter to attract them. For example, a dead rodent will attract bluebottle as would rotten food that has not been properly disposed of. They are larger than the housefly and have a distinctive blue hue on their back and abdomen.
The cluster fly are more common in rural areas than urban. They are a flying insect that start out as a parasite of the earthworm and who hibernate for the winter as adults. They usually congregate under roof tiles or in the membrane under the skin of a flat roofed building or similar. In well maintained properties, they emerge prematurely from hibernation (often in the evenings when the central heating warms up the building and their place of rest as the heat rises). From here, they are attracted to light and manage to squeeze their way in to the building by following the ‘borrowed light’ from upper floors.
They then tend to congregate on window ledges but at all times are lethargic and unable to fly very well. There can literally be thousands in one over-wintering site so the evidence on internal window boards can be an everyday event until the problem is treated. This usually involves treating the roof space to get to the source of the infestation. Preliminary precautions must always be put in place before any treatment commences.
Beerfly are common in bars where they are prolific breeders. They do tend to congregate around the sweeter liquers and cordials and cause discomfort for customers. They are a huge nuisance and the reasons for their presence can be varied. From poor housekeeping to poor quality bar counters and shelving, to a pinched line or a leak, beerfly can not be eliminated without identifying and rectifying the core problem and then carrying out insecticidal treatments to mop up strays.
Drain flies are usually present because of a blocked drain and likewise for the sewer fly. Again, in like manner, fruit flies are attracted to rotting fruit or fruit peel. Unless the source is identified and rectified, no amount of insecticide will provide anything more than a very minor reduction in populations.
There is a huge variety of flying insects in Ireland and it would be impossible to profile every single species on a single website. Pest profiles of flying insects (not included in these pages) can be had by clicking on 'ASK A PRO' and submitting photographs and questions to our resident Biologist.