Another insect that makes our summertime miserable is the blackfly. Its mouthparts are adapted to cut the skin and hold on to it with hooked hairs. Then, females suck blood from the wound. Their saliva contains enzymes that liquefy the blood and prevent it from clotting. Blackflies found in Poland do not transmit diseases, but they secrete highly toxic saliva. Their bite can cause (more often than a mosquito bite) swelling, redness and high fever. Like mosquitoes, blackflies inhabit wetlands near bodies of water. Blackflies often fly in swarms. The males feed on the flower nectar and plant sap. Only the females are dangerous to humans, and only during the day – especially in the afternoon and evening. Swarms of blackflies attack both animals and humans.

After a bite, due to the toxic constituents of blackfly saliva, the skin may develop a strong allergic reaction which can last up to seven days.

At the site of the bite, a small wound, which can become infected if scratched, is formed. The site of the bite should be washed. A remedy relieving itching and inflammation should also be applied.

If the wound gets bigger and swollen, consult a doctor who can apply a topical antibiotic.