Legal Question in Civil Litigation in Florida

Only if you ate it and it caused you to become sick and you suffered financial damages due to emergency medical treatment or extensive hospitalization and/or extreme emotional distress, unless you can prove that McDonald's put the insect in your salad intentionally, and especially if the company knew that you had a propensity to be particularly sensitive to the sight of dead insects and that seeing a dead insect would cause you extreme emotional upset, but they did this particular act specifically to bring about the extreme pain and suffering that they could foresee that you would suffer.

short answer: probably not, you should have taken it to the counter, and asked for a free salad. The manager would have gladly obliged.