Bees such as this Eastern Carpenter Bee
pollinators, though sometimes a plant may trap the pollinator.
The Common Milkweed
has pollen tucked away in packets called pollinia.
obtaining nectar inserts its legs in the slits surrounding the pollinia,
usually carrying off the packets, but sometimes getting stuck.
Butterflies such as Monarch
can be mutualistic pollinators as adults,
though the juvenile caterpillars
are predators as leaf eaters.