I went down the Mekong River from China to Thailand in about 2006 and there were thousands of insects that would flock to the boat when it moored overnight. I r

I went down the Mekong River from China to Thailand in about 2006 and there were thousands of insects that would flock to the boat when it moored overnight. I repeated the trip in early 2016 and there were almost none. Deforestation and the replacement of virgin forest with rubber plantations appeared to be the main factor, but at a guess the use of pesticides was probably also to blame.