The flowers are pollinated by bees, but can self-pollinate. Houndstongue may be pollinated by bees, and may also self-pollinate. Cucumbers may also be pollinated by bumblebees and several other bee species. Cactus flowers are pollinated by insects, birds and bats. They are mainly pollinated by bees and moths. The flowers are pollinated by insects, primarily by Hymenopteran insects. Moreover its flowers are pollinated by bees. "Brugmansia arborea" are usually pollinated by moths. The flowers are pollinated by insects, especially hoverflies. The flowers are pollinated by bees. They are pollinated by insects such as bumblebees and carpenter bees, and are self-sterile. Brassicaceae are almost exclusively pollinated by insects. They are pollinated by small bees and flies. First, flowers are pollinated by insects. Trees can be pollinated either by wind or by animals, mostly insects.