Some flowers are open and with nectar all day and night, but others are open only for a few hours in the morning, afternoon or night. The single worker bee learns and remembers what time the different flowers are worth visiting. One bee can remember the opening time for up to seven different types of flowers. The honeybees are pollinating a great number of different plant species, and they do it effectively. Some solitary bee species are much more specialized for pollinating specific plant species.