Midges Making Climate

Mücken machen Klima was the title of an article in the Badische Zeitung about the Büschelmücke. When I looked up the equivalent in the English Wikipedia, I read: The Chaoboridae, commonly known as phantom midges or glass worms, are a family of fairly common midges with a cosmopolitan distribution.

Why would a midge influence climate, even if billions of them exist? What I did not read on Wikipedia, are recent research results by the Universities of Geneva, Swansea, and Potsdam teams. The scientists confirmed that for two years, the larvae of Chaoboridae live in muddy pools and ponds, preferring eutrophic waters where they will reach densities of up to 130,000 larvae per square meter. They feed on water flies, springtails, and other mini beasties but only during night hours. During the day, the larvae hide from their predators by diving up to 70 meters deep into the muddy bottom of the water.

Chaoborida larva or glass worm (©Wikipedia)

Long before submarines were developed, Chaoboridae larvae used the technique of submersion. The research showed that while waiting on the bottom for the sunset, the "glass worms" start to fill their ballast tanks with methane until they drift to the surface. Here they stabilize in their hunting position. The larvae release all methane at dawn until they sink to the bottom again. It is all a question of energy, as the scientists calculated. Even if the larvae catch four water flies in 24 hours, they would need 80 % of the gained energy to dive by mechanical means. The submersion technique is an evolutionary success for Chaoboridae but seems to be a catastrophe for the climate.

Büschelmücke (Chaoborida). Note the Büschel (tufts) (©Wikipedia)

The scientists attribute nearly 8 % of the total global methane emission to the midges as they release additional methane when stirring up the mud in the grounding process. With the melting of permafrost in Arctic regions, captured methane is released "naturally," and the formation of water puddles will enlarge the Lebensraum (habitat) of the Büschelmücke, i.e., there is more muddy water to place their eggs. So Chaoboridae will actively amplify the "natural" methane release due to rising Arctic temperatures. As for animals, only cows contribute more methane on a global scale (27 %) than the midges.

Shall the community sponsor further research on Chaoboridae? Here on the Upper Rhine, Freiburg's authorities are instead quarreling about the financing of a campaign against the tiger mosquito. It came in lorries from southern Europe and hibernated in our region. So globalization and climate change are stimulating the Asian mosquito to move farther north, spreading angst about new diseases.

Tiger mosquito (©dpa)

An expert said that in Freiburg's north, an allotment garden is infested with tiger mosquitos: There are lots of nests, and many of the larvae are hatched. Their next leg would be Freiburg's central cemetery with all its watering pots, which would make the tiger mosquito spread out of control.

Why do the Freiburg authorities hesitate to spend 50,000 euros? Well, fighting the tiger mosquito with a chemical mace would result in collateral damage to other insects, but who likes to see the birds starve? In fact, a recent census in Freiburg has shown that the population of birds within the city boundaries has dramatically decreased over the last years, a trend due to a more and more restricted habitat for birds in combination with less food.

Another circulus vitiosus.

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