nectar is not sugar and water. in simplest terms it can contain sucrose, glucose, fructose, amino acids, vitamins, oils and, some say, proteins.

adult hummingbirds digest a small amount of pollen while they collect it and feed it to their chicks.

it is there in the plants they visit as are gnats and other insects which are attracted to the nectar and are eaten by the hummingbird upon accidental meeting.

and yes most hummingbird species hunt spiders as well as use the webbing in their nests.