How are poinsettias pollinated?

Yes, bees can help pollinate poinsettias (Euphorbia pulcherrima).

Specifically, green bee members of the Halictidae family often visit poinsettias planted outdoors in Florida. The bees are drawn to the plant's color and scent. While sampling the plant's nectar, they pick up grains of pollen. The pollen stays on their bodies until dropping off at the next poinsettia visited. Bees thereby help pollinate the poinsettias that they visit.