This is not an insect or a reflection on the lens of the camera. Unknown, and a good catch by the viewer.
Interesting - but it could still be lens flare from an object outside of the frame, reflecting the bright sun.
If not lens flare then, who knows?! A joke by the director? Aliens, dropping by, to see what all the fuss is about? :-)
I think it was put in intentionally to create more buzz for the movie. It just seems too obvious. Right?