Aah, yet another helpful writeup from webster. I can do one better...
Latin name: Aphis (genus name)
Aphids are insects that exist wherever plants exist. They are many things to many people.
They are best known to humans as tiny agricultural pests that hurt crops.
They are best known to plants as little bloodsuckers that weaken the plant and leave it succeptable to disease and fungal infection, as well as hurting fruit.
They are best known to ants as useful little creatures that should be protected and guarded, as they can be farmed for the sweet honeydew they excrete.
They are best known to fungi as useful terraformers that excrete honeydew on plants, allowing fungus growth. And if this growth obscures the leaves or hurts the fruit or makes the plant ugly, so what?
They are best known to ladybugs and their ilk as a tasty snack that goes down great. This is why farmers will sometimes buy ladybugs by the gallon.