Hot topic: The ecological winners of the mini May heatwave

When Ireland gets unusually warm, nature pays attention. A burst of warmth in late May can change behaviour, accelerate life cycles and create ecological winners. Not every species dislikes heat. Some quietly thrive

Mosquitoes are ectothermic, so temperature matters. Warmer conditions can accelerate development from egg to larva to adult where suitable breeding habitats exist. Picture: iStock

Three days above 25°C in Ireland and the country briefly forgot who it was. And it was fantastic. Barbecues appeared with unreasonable optimism. Pale legs emerged blinking into daylight. WhatsApp groups filled with messages like, “We should go to the beach,” as though half the population had collectively relocated to southern Europe. And then, just as quickly, it began to turn. Because Irish warm weather comes with an unspoken understanding: enjoy it while it lasts. But while we’ve spent the past few days chasing ice creams and searching for sun cream that expired in 2022, something else was happening. Ireland’s ecosystems were responding. Even a short burst of unusual warmth in late May can change behaviour, accelerate life cycles and create ecological winners. Not every species dislikes heat. Some quietly thrive.

For bees, hoverflies and butterflies, warm spring weather can mean opportunity. Insects are ectothermic, meaning their body temperature and activity are strongly influenced by surrounding conditions. When temperatures rise, many pollinators can fly more readily, forage more actively and visit more flowers. In late May, when hedgerows, gardens and meadows are already busy with flowering plants, a warm spell can turn the landscape into an airborne motorway. That matters because pollinators are not decorative extras. They are part of the living infrastructure of the countryside. The Irish Pollinator Monitoring Scheme tracks wild bees, hoverflies, butterflies and their floral resources, while the All-Ireland Pollinator Plan notes that one-third of Ireland’s wild bee species are threatened with extinction. Habitat loss and reduced food availability remain major pressures. Warm, sunny weather may help pollinators in the short term, but ecology rarely gives simple answers. If heat is prolonged, plants can become stressed. Dry soils may reduce nectar production. Flowering periods can shorten. So, while bees may be busier, the floral café may not remain fully stocked. The weather that gets insects moving can also affect the food they are moving towards.