Failing all that a dry ice spray will freeze 'em to the branches   

I'm only joking !!!
Good tips there to help get some great natural shots. Knowing a bit about the creature you are shooting helps a great deal.  For example: Darter dragon flies will readily use a hunting perch that you put there for them if it is in the right place and most suitable perch around for their purpose.  Observation is key to get to know their habits.

And every one said, 'If we only live,
We too will go to sea in a Sieve,---
To the hills of the Chankly Bore!'
Far and few, far and few, Are the lands where the Jumblies live;
Their heads are green, and their hands are blue, And they went to sea in a Sieve.

Edward Lear
http://www.nonsenselit.org/Lear/ns/jumblies.html