Non-biting midges (Chironomids)
Non-biting midges are two-winged flies that spend most of their life cycle in lakes. They are found all over the world and are abundant in lake sediments, which makes them very useful for studying the climate of the past. The heads of non-biting midges are made of chitin, a robust material, which means that this part of the insect is well preserved in lake sediments. Features on the insects' heads are used to identify individual taxa. A number of the non-biting midge taxa prefer specific environmental conditions, and are therefore highly sensitive to change. Extracting non-biting midge heads from the sediment and using a microscope to identify them is painstaking and labour intensive, but once enough of them are collected researchers are able to work out what the climate was like in the past.
In this video Dr Eleanor Maddison shows how midges are extracted from the sediment cores collected in the North Atlantic region and used to reconstruct past climate:
Tipping Points - Uncovering the Climate of the Past in Greenland - Part 2
Scientists travel to Greenland to collect environmental samples that will help them uncover the mystery of a rapid cooling event that took place in the North Atlantic around 5000 years ago. This will help to discover how the Earth's climate systems may change in the future.
(Head capsule approx. 0.3mm across).
Photos Credit: E. Maddison
Midges live most of their lives in lakes and are sensitive to climate change. This is because temperature of lake waters is influenced by changing climate.