Blue Ynts like to eat just like every other being (or.. almost every other being), for example fruit, sandwiches or, preferably, something they can attract with a sandwich.
Klaymen would be one of those somethings. But he sure wouldn't be so silly (or hungry) to fall for an unknown sandwich waved in front of his eyes, right? Er.. right..?
Well, you'll find it out after you pass the level Ynt Weeds.