The Midge Life Cycle

Different species of midge have different life cycles, the description here applies to the the Highland Biting Midge, Culicoides impunctatus. Some other biting midges have similar life cycles.

The midge begins life in the summer and it is the reproduction of the midge that is responsible for their biting behaviour. Once fertilised, the female's eggs cannot properly develop without a blood meal. For this reason she hunts down her prey - often us. Every time you are bitten by a midge you are probably helping the next generation to be born!

One reason for the abundance of midges is that they produce two generations per season. The Highland Midge is "autogenus" - the female's first batch of eggs doesn't require a blood meal. Subsequent batches do.

A female midge will typically lay two batches of eggs. The first can contain up to 200 eggs, the second is usually smaller at up to 30. These are normally laid in moist soil, often by water. The larval midge emerges within a day or two and burrow into the ground. Under the right conditions just a few square yards of ground can contain hundreds of thousands of midge larvae.

The larvae go through four stages ("instars"), a process that takes about four weeks. Larvae from the first egg batch emerge later that same year, those from subsequent batches spend the winter underground.

The fully developed midge larvae go through a short pupal stage of one or two days. In the case of second batch larvae that have spent the winter underground, this process is triggered by the warmer weather and usually takes place in May.

Finally the adult midge emerges from the pupa, after which it has a lifespan of some 20 to 30 days in the wild. In laboratory conditions adult midges can live twice as long as this.