Plants for Wild Bees—Field Records in Bulgaria

One of the eight shortfalls in European wild bee data is the knowledge of the flowering plants they favor. This knowledge is of particular importance for bee gardens and wildflower strips initiatives aiming to provide forage for the wild bees. The aim of this study is to provide a list of plants that are used for food by certain taxa of wild bees in Bulgaria and to evaluate their potential for cultivation in bee gardens and wildflower strips. In relation to this, we discuss the food plant specialization of the wild bees. We summarize our observations on the pollination of certain plants and faunistic records considering the food plants in several grassland habitats on the territory of Bulgaria at altitudes between 0 and 1500 m above sea level, during the last 30 years. More than 54 taxa of wild bees are listed. They belong to the families Apidae, Andrenidae, Colletidae, Halictidae, and Megachilidae. Some of these bees are identified to the species level, and others to the genus or family level. Among the recorded wild bees are observed eight oligolectic species (22.2%). The listed bees are flower visitors of 60 plant taxa belonging to 20 families, which offer nectar and/or pollen. The wild bees’ food plants are predominantly from the families Fabaceae (15 species), Lamiaceae (14 species), Asteraceae (9 species), etc. The perennials are 67%, while annuals are 9%, annual or biennial 6%, biennials 5%, etc. We discuss the seed germination specifics of these plants. More studies are needed in this field. The conservation of wild bees may be supported by wildflower restoration activities, but the process depends on many factors, including seed germination difficulties. Therefore, the natural grassland habitats must be preserved and protected.