I agree that mayflies tend to face downstream.
There are two possible reasons. One is the aerodynamic reason that they mayflies orient INTO the wind and the downstream current creates it's own breeze by moving the insect through the air.
The second possibility is that as the nymphs migrate up through the water column, they naturally face downstream as they rise. They rise in the direction the current is moving because it requires less energy. Therefore, they will also emerge facing downstream.
I knew of a fly tier who tied his flies so the tails were over the hook eye and the wings were at the back of the fly. He preferred fishing downstream.
I don't know if reverse tying the fly makes a significant difference.
I will take issue with the belief that the downstream cast is LESS effective than the upstream cast. Actually, the most difficult fisheries require a downstream cast if one is to catch fish with any regularity. Difficult fisheries such as the Railroad Ranch section of Henry’s Fork and Silvercreek Preserve in Idaho require the downstream technique.
See this post:
I suggest that everyone listen to the podcast on Silver Creek that is playing free now at:
To download a show:
- Locate the Listen/Download Podcast (MP3) link on the show page, then right-click or Ctrl+Click (for Mac) on the link. A contextual menu will display.
- Choose Save Target As, Save Link As or Download Linked File As. The menu option name will depend on the browser you are using.
- A browsing window displays that you can use to find a location on your computer's hard drive to save the file. You may want to rename the file at this time using the show title.
- Save the file.