Different weevils will have different primary food sources. Weevils like the boll weevil feed on cotton buds and flowers well the wheat weevil lays eggs which feast on the inside of grain kernels.
The primary souce is the SUN
the primary food source for the artic fox is the Harp Seal
food
Corn or maize was a primary food source.
It will do nothing but provide a food source for some species.
PLANKTON
Plankton.
The Sun
This one
Food
It is the sun.
food webs contain many food chains however a food chain shows only one primary source and food webs contain more than one primary source.