Of oil flowers and oil bees

In 1969, botanist Stefan Vogel first described flowers that offer fatty oil instead of nectar to attract their pollinators. Today, biologists recognize about 1,800 examples of such "oil flowers" worldwide. The only representatives in the native flora are the loosestrife species (Lysimachia).

Bees of the genus Macropis collect their oil with the help of fine, dense hair brushes on their hind legs. These act like a sponge in the process. The female mixes the nutritious and at the same time fungus-inhibiting flower oil with the pollen of the plant for larval food.

The walls of the underground brood chambers are also impregnated with flower oil. This allows the bee to nest in moist soils where common loosestrife, its main food plant, grows. It nibbles nectar on various other flowers in its environment.

Image captions:
Loosestrife - bright yellow on wet soils.
Moneywort (Lysimachia nummularia L.) is even offered as an aquarium plant.
Macropis fulvipes on flower of spotted loosestrife (Lysimachia punctata L.).
Male (left) and female (right) of Macropis fulvipes.

English translation of the information panel in the Botanical Garden. Original German text: Dr. Barbara Ditsch