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The Mayfly is the largest and most spectacular up-winged fly in the UK. There are three species:
The commonest on the River Tillingbourne at Albury is the Danica. We often see Vulgata but I have never knowingly seen Lineata - although it is sometimes known to occur on the Thames.The specimen in the photograph is Ephemeridae danica and was found during May 2005 in Upper Beat.The larvae burrow in silt or sand and have always thought to have two years in the river before hatching. There is now evidence that with warmer winters this is changing to a one year cycle. We seem to have reasonable numbers of larvae - they are almost always present in our sample and with quite a variation in size. They usually start hatching towards the end of May but over an extended period. Unfortunately we don't get the massive hatches seen in the past on the Tillingbourne.
Estimated Numbers: ASI 1: 1-9 ASI 2: 10-99 ASI 3: 100-999 ASI 4: 1000+ |
