The Presence of Insects in Ireland
Ireland’s varied landscapes are home to a diverse array of insects. Ireland supports thousands of insect species, including butterflies, bees, beetles, moths, and various flies. Over 11,500 insect species have been identified in Ireland, with estimates suggesting the true number could be as high as 16,000. These creatures fulfill a range of ecological roles, contributing to pollination and the decomposition of organic matter. Insect activity increases during warmer months, peaking in summer.
Common Outdoor Insects
Certain insects are commonly encountered outdoors in Ireland. Midges, biting flies, are particularly noticeable from mid-May through September, especially in calm, overcast conditions near damp areas like bogs, lakes, and woodlands. Only female midges bite, seeking a blood meal to produce eggs, and while their bites can be itchy, they do not transmit diseases to humans in Ireland. Avoiding outdoor activities during peak midge hours, early morning and evening, and using insect repellents containing DEET can help reduce bites.
Mosquitoes are also present in Ireland, with at least 18 species. They are most common in late summer and early autumn, often found near standing water. Irish mosquitoes do not carry human infections. Their bites are a nuisance, not a health concern.
Ticks are also present outdoors, found in grassy and wooded areas, active from spring to autumn. Around 5% of ticks in Ireland can carry Lyme disease bacteria. To minimize exposure, wearing long clothing, tucking trousers into socks, and using insect repellent are advisable when outdoors. After outdoor activities, thoroughly check skin (especially warm body folds and scalp) and pets for ticks. If a tick is found, remove it carefully with fine-tipped tweezers, grasping close to the skin and pulling upwards slowly, then clean the bite area.
Horseflies, whose females deliver painful bites, are most active during daylight hours, particularly in July and August. They are drawn to warm-blooded hosts, including humans, and are prevalent near livestock, woodlands, and damp areas. These flies are attracted to sweat, body heat, and carbon dioxide.
Insects in Homes and Gardens
Various insects and other invertebrates are commonly encountered in Irish homes and gardens. House spiders frequently visit indoors, particularly during cooler months when seeking shelter. Ireland is home to approximately 370 spider species; most are not dangerous to humans, but some can bite if threatened. Bites are mild and rarely medically significant. Spiders are also beneficial by preying on other insects. The false widow spider, an introduced species, is present; its bite is typically compared to a wasp sting, and these spiders are not aggressive.
Ants are common household visitors, especially the black garden ant (Lasius niger). They are attracted indoors by food sources, particularly sweet substances, and are more active during warmer months. Large numbers of flying ants are observed during summer as part of their mating cycle. While a nuisance, ants pose no danger to human health.
House flies are frequently found in domestic settings. Though common, they can transfer pathogens.
In gardens, slugs and snails, though not insects, are abundant due to Ireland’s damp climate. These molluscs can damage garden plants, especially tender seedlings. They also play a role in decomposition and serve as a food source for other wildlife.