Hi yijiawang, that's a very interesting question!
This is the best I was able to find on Phalaenopsis pollinators online, I hope this link works:
Phalaenopsis: a monograph - Google Books If it doesn't, go to Google Books and search 'phalaenopsis pollinator', that's how I found this book excerpt.
Here is another thread on OB in which member cneos discusses pollinators of some Vanda species:
Vanda denisoniana. The actual discussion of pollinators starts on the second page. You may want to ask member cneos for more details... Hope this helps, and please let us know what else you find out!
--Nat