KQED Science has a interesting video about the relationships between California Pipevine plants, PIpevine Swallowtail butterflies, and the gnats that pollinate the plants

The devilish caterpillars of the pipevine swallowtail butterfly *devour* the California pipevine, never mind that the plant is trying to poison them. Their butterfly moms don’t pollinate the pipevine in return, though. So, the vine traps unlucky gnats in its labyrinthine flowers to do the job.

See video and read more at The Pipevine Caterpillar Thrives in a Toxic Love Triangle | Deep Look