Are my turn signals invisible?

We were returning from a trip on Memorial Day and the two lane highway narrowed to one lane due to construction. My lane was ending, so I put on my left signal. There was a huge group of bikers coming up and the front couple of bikers sped up so I couldn't get over. My lane was fast ending but they kept coming and wouldn't let me over. So, like some of you have posted, I just kept merging left. I gave them plenty of time to slow down or speed up (they were going just slightly faster than me). Finally one yelled at me as he was next to me. I just kept going left and had to force my way in. I guess that if they thought that the were a match for my truck and trailer then Darwin was at work. Didn't like to do it, but had no choice. I guess they had slightly more brains than they looked like they had because some slowed down rather than kiss the "Jersey barrier".