How many species of wild bees?
The wild bees are so called as opposed to the honey bee (Apis mellifera). Unlike the latter, wild bees constitute a vast taxonomic group, extremely rich in terms of biology and ecology, which includes nearly 1 000 species in France and more than 2000 species throughout Europe. Worldwide, it is estimated that there are more than 20,000 species.
What is their diet?
In France and Europe, solitary bees are represented by 6 families that can be divided into two groups according to the size of their language:
The group of short-tongued bees
adapted to flowers with open corolla
(daisy, rose, …): Andrénidés, Collétidés, Hallictids and Mélittidés.
The group of long-tongued bees
adapted to long-corolla flowers
(clover, gentians, …): Apidès and Megachilidae.
Some characteristics :
Bees are characterized mainly by the presence of brushes of branched bristles, which allow them to harvest and transport pollen efficiently.
This anatomical trait is directly related to their diet. Indeed, adult bees as well as larvae feed exclusively on the resources collected in the flowers: nectar and pollen:
– Pollen provides them with proteins, carbohydrates, fats, vitamins and mineral elements,
– Nectar is a source of water and sugar.
The presence of this highly efficient harvesting tool explains why these species have close relationships with flowering plants and participate widely, if not exclusively in some cases, in the reproduction of many of them as pollinators. Indeed, the great diversity of solitary bees has allowed the appearance of a food specialization. Species that collect pollen from a single family or genus of plants are called “oligolectic” and “polyelectric” are those that forage for several families of plants.
They appear from the beginning of spring, with the flowering of willows, until the end of October, on ivy. The floral resources of a habitat must therefore be sufficient to cover the dietary needs of adults and larvae but must also be present long enough to meet the needs of the different species that follow one another during the year.
As in the majority of insects, 4 stages are observed in the life cycle of a solitary bee: the egg, the larva, the nymph and the adult (imago).
Females each lay one or two dozen eggs, placed in individuallarval cells that contain the food resources necessary for the development of the larva. After a few weeks, the larva turns into a nymph that remains in its cell without feeding for several months. Depending on the species, the adult leaves the nest between early spring and late summer.