A rostrum is a raised or elevated platform or pulpit usually for addressing an audiance As related to biology is a beaklike process or extension of some part. For example, the great white shark, it is pointed above the nose, that is the rostrum.
For several reasons, but a key one would be that a diet of insects require sharp, strong teeth for crunching exoskeletons, while nectar wouldn't really require any teeth. The needs of the creatures...
A rostrum camera is a specially adapted http://www.answers.com/topic/movie-camera-1 used in http://www.answers.com/topic/television and http://www.answers.com/topic/film to animate a still picture or...