Oenothera biennis Ecology

When opening the first flowers dust the mature anther, which is why the flower is known as foremen. The pollen grains of the dust bags are matted together and stay on Viscinfäden thereby hang easily in the hair or on the antennae of insects. Only when the dust bag has been emptied, the mature scars. These are immediately after anthesis still closely together and unfold themselves in the course of the opening of the flower. Nectar for pollinating insects at the base of the calyx tube separated by a smooth, yellow honey gland, which lies above the ovary. The nectar flows due to the horizontal position of the flower to the exit where he sticks to the lying pen.

A special feature of Commons evening primrose, is that the pollination of evening primrose flower is made mostly of moths, which in the summer, arriving about 30 minutes after the opening of the flowers, the smell is most intense. This observation can be made even in the big city, where evening primrose are planted, for example, on roof gardens. The moths, which are in evening primrose flowers of Commons to be observed, especially among the family of enthusiasts, including Hummingbird (active during the day!) And the most common in Central Europe Schwärmerart, the Middle wine enthusiast. A fanatic is rather rare in Central Europe because of his fondness for the nectar of this plant even called evening primrose enthusiast.

The moth can occasionally observe how they are hovering in front of one of the flowers. When inserting the proboscis, they roam the anthers of the flower. The scars are a result of lateral movement of the stylus initially moved away from the direction of access to the nectar. Half an hour after the opening of the flower extends also the style. Its stigma lobes spread apart is there and can now be dusted with pollen bearing the later arriving insects with it.

By day, ask yourself one attracted by the bright yellow color of the petals with the invisible to humans Strichsaftmalen also langrüsselige, honey bees and bumble bees and butterflies seeking. Occasionally seen on the leaves of Commons evening primrose and up to eight centimeters long caterpillar of the Middle wine enthusiast with the characteristic crescent-shaped eyes and white spots edged on the first and second abdominal segment. This specialized normally willowherb caterpillar can also use the common evening primrose as Fraßpflanze.
Source: http://de.wikipedia.org/wiki/Gemeine_Nachtkerze

See Also: Sending Flowers, Online Florist