Do arthropods pollinate plants

Answer 1

Yes. The most sophisticated example is the bee dance, with which bees tell eachother where food is to be found, how far away and in which direction. Arthropods also communicate a lot by pheromones, mainly to let partners know where they are and when they're fertile. Moth males can smell females miles away, but some Spiders play into this by mimicking the female's scent! This, too, is communication... And of course, ants recognize members from their own colony by stroking antennae together, and they're not unique in this.

Answer 2

It would depend upon the arthropod. Arachnids, centipedes, and crustaceans do not pollinate plants. Some insects do, but some do not. Ants do not. However, bees and some moths do. You would have to be more specific as to which arthropod you are talking about to better answer this question.