The last time you could call, mayflies, a “May” fly was in the 1980.

Since the 1980’s a lot of us fly fisherman that drove many hours to get to a “spectacular” mayfly "hatch" or emergence and found it happened weeks before. Previously you could set you watch to those mayfly hatches since they were espoused by Theodore Gordon in 1900.

Flyfisher people have known about global warming since the 1980’s. Now before making a long trip they ask the locals how many days the “hatch” has moved up.

You see for the most part aquatic insects cannot move around. If conditions change in the water (warmer) they cannot adapt. They die off. That is the reason macroinvertebrate surveys are the most reliable indicators of waterway health.

It is interesting that the tornado season now begins in early February instead of May.

http://news.bbc.co.uk/2/hi/americas/7883024.stm