Andrena

Pronunciation

How to pronounce Andrena: /ænˈdriːnə/

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Summary

Andrena, a genus of mining bees in the family Andrenidae, comprises over 1,500 species worldwide, recognized by their ground-nesting lifestyle, distinct morphology, and role as pollinators.

Physical Characteristics

Andrena are generally medium-sized bees, with a body length ranging between 8 and 17 mm. Males are usually smaller and more slender than females. They are predominantly black with white to tan hair, and their wings possess either two or three submarginal cells. Unique identifying features include facial foveae (broad velvety areas between compound eyes and antennal bases) and a ring of hairs on the underside of their face known as the 'subgenal coronet.'

Identification Tips

To identify Andrena, look for the facial foveae and the presence of the subgenal coronet. Identification to species level usually requires expert knowledge due to similarities among species.

Habitat

Andrena bees prefer sandy soils for nesting and can be found in various habitats, commonly in temperate regions with a Mediterranean climate.

Distribution

Andrena is distributed in temperate regions of Europe, Asia, and North America, with a small number of species in sub-Saharan Africa. They are absent in South America, Australia, nearby islands, and Madagascar.

Diet

Many Andrena species are host-plant specialists, visiting flowers of only a single or closely related plant species. Some species have evolved to specialize on pollen from specific families, such as Asteraceae for members of the subgenus Callandrena.

Life Cycle

All Andrena species are ground-nesting and solitary. Mating occurs shortly after overwintering adults emerge in spring, with females constructing nests and provisioning them with pollen. Each female typically has one generation per year, and adults are only active for a few weeks.

Reproduction

Females build nests consisting of vertical tunnels lined with a shiny waterproof secretion, where they deposit pollen provisions for the larvae. Larvae do not spin cocoons and overwinter as adults.

Predators

Nests are attacked by various insects including brood parasitic bees (such as Nomada), blister beetles, parasitic flies, and Strepsiptera.

Ecosystem Role

Andrena plays a significant role in pollination, particularly in colder conditions where they may be more efficient than other bees.

Evolution

Andrena is a strongly monophyletic group that displays significant morphological and behavioral adaptations for their pollen preferences, indicating a complex evolutionary history, particularly with regard to their oligolecty.

Tags

• Andrena
• Mining Bees
• Hymenoptera
• Pollinators