The culicids are the well-known mosquitos with biting adults. Their swimming larvae are distinguished from other true flies by their wide thorax (the widest part of the body) and the presence of a breathing siphon (usually) at the end of the abdomen. The pupae are often referred to as “tumblers” due to their tumbling swimming motion.
Culicid larvae and pupae can be abundant in all sorts of stagnant fresh waters, including ponds, drains, house gutterings or anywhere rain water collects.
They use brush-like mouthparts to collect floating organic matter or to scrape organic slimes from submerged surfaces.
Culicid larvae can be abundant in natural lakes and ponds, but also in low oxygen pools filled with decomposing organic matter. They have low tolerance values of 3 (hard bottom sites) and 1.2 (soft bottom sites).