You probably know all about pollinators…bees land on flowers to collect pollen and nectar, and because they’re fuzzy, they end up transferring pollen to different flowers, resulting in genetic recombination.
But maybe you didn’t know that not all bees visit flower the *right* way. That is, the morphology of the flower should encourage bees to enter through the opening in the corolla formed by the petals. This should force the bee to brush up against the reproductive parts of the flower, thereby enacting pollination.
And some bees cheat.
They cheat because they are TOO BIG to fit in the normal way. Instead, they chew a hole through the base of the corolla, and drink the nectar through the side. They never touch the reproductive parts of the flower.
Now, the number of species that can be primary robbers is limited; mainly it includes only carpenter bees (like our friend Xylocopa virginica here) and some species of bumblebees. These bees are not always exclusively robbers. In fact, they visit some species of flowers the *right* way and some the *wrong* way.
Biology is confusing.