They're not exactly controlling the aphid outbreak in a very noticeable way but every little bit helps. Not sure of the exact identification but I'm pretty sure these little braconid wasps are why I keep finding aphid "mummies" - hollowed out brown shells of aphids that have been used [eaten from inside out] by the braconid wasp larva. Ghoulish but it's all part of the web of nature and they're helping me avoid an all-out aphid epidemic.
Little Aphidius sp. (???) wasp, maybe hunting for an aphid to lay an egg on...
An aphid "mummy"
Closer view of an aphid "mummy"
learn more about Aphidius sp. - parasitizing aphids