It is a good idea.  Instead of a clam, this seemed to me like more of a snail thing to do.  Snails are clam cousins so it is close.  Plus snails already live on land, and your tree canopy seems like snail heaven.  I went looking.

This quote is about the "pond snail" of which the Lymnaea species is one.

https://homesteady.com/info-12285231-long-life-pond-snail.html
> The snail leaves an underwater slime trail, which collects plant and
> animal debris as well as microscopic organisms. Upon crossing its own
> slime path, the pond snail eats the bits and pieces stuck to the trail

Better is this great stuff on pond snail feeding I found on Google books from [Behavior monographs.
	Cambridge, Mass. : H. Holt & Co., 1911](https://books.google.com/books?id=Y3oVAQAAIAAJ&pg=RA2-PA71&lpg=RA2-PA71&dq=snail+mucus+ribbon+feed&source=bl&ots=_M6vbygYeQ&sig=JpG7FQnKcy4a6h3VmZZhxahnlcE&hl=en&sa=X&ved=0ahUKEwip0ILl_YbcAhUk3YMKHXChDRgQ6AEIiwEwFA#v=onepage&q=snail%20mucus%20ribbon%20feed&f=false).   I love these old natural history descriptions!

> All of these flesh eating snails have been seen eating dead
> houseflies, mayflies, fish, beefsteak and snails. They will eat such
> meat fresh, although they seemingly prefer it stale. I had seen them
> eating dead snails, when the odor from the food could scarcely be
> endured in the laboratory. The *Lymnaea* cited above have cannibal
> traits, a character which is especially notable in *L. stagnalis*.  I
> have seen this species devouring struggling flies, moths and young
> snails that have become entangled in its slime…
> 
> It is a common thing to see *Lymnaea stagnalis* and other freshwater
> pulmonates turn about and eat from the foot the mass of somewhat
> hardened mucus together with what foreign bodies this has
> incorporated.  Linden (1902)  has observed the dexterity of *Lymnaea* in
> obtaining food from the foot, while the snail is moving upon the
> surface film. Brockmeier (1898)  describes this process as “plankton
> fishing”. The mucus servers not only as a food itself but is a most
> efficient means of collecting food for the snail, both on solids and
> on the film. The trails of mucus left on solids remain sticky and
> serve as a trap to catch my new plants and animals and other foreign
> particles.   The snails eat continually from the solids, devouring the
> mucus with all that is caught in it.

So: a mollusk which secretes sticky mucus from the foot, then eats the mucus with live prey that has stuck to it.  That is what you want and that exists!  A snail would probably not mind being sessile most of the time, waiting for its prey to come to it.  

It is one more step to having attractive smelling mucus.  I could imagine mucus that stunk could attract flies although that might attract larger carrion feeders too which would eat the snail. The same problem exists for fruit smells - fruit flies are tasty but big things like fruit.  Mucus that smelled like flowers could attract pollinators - that sounds right.


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I was thinking of this concept and a snail that let its viscous slime net drool down thru the air like flypaper.  Then it would reel it back in with its haul of bugs.