thiare haorangySolitary bees make up more than 90% of all bee species worldwide. To get a better understanding of solitary bees, we need to look various factors. These include their environment, nesting and feeding habits.
Most species of solitary bees collect pollen from a variety of different plants (polylectic), but some bees are very particular. They only collect pollen from one or a few selective plants or plant species (oligolecty). Solitary bees are generally not aggressive species.
Honey bees can forage much larger distances away from their nest than the smaller-sized solitary bees, which are also more picky about their food. Solitary bees therefore build their nests close to where they find plenty of their preferred food.
Solitary bees often nest in aggregations. This means they build their nests in close proximity to each other when plentiful food sources like flowering fields of crops are close by. A few species even share a single entrance hole in the ground. Although it may appear like a colony, these so called communal solitary bees each build their own nest inside the burrow.
Solitary bees nest in various places depending on the species. They include underground burrows, cracks or crevices of walls, wood, tubes, aerial nests, or snail shells. Those found in insect hotels are generally aerial nesting species, which usually nest in holes excavated by beetles. Many species have anatomic differences including color and size depending on their purpose.
Species of Solitary Bees
Solitary bees fall into three major categories, i.e. parasites, mining bees and cavity-nesting bees:
Not all bees collect pollen, some are brood parasites or cuckoo bees, with no pollen collecting apparatus. Around 20% of the global population of solitary bees are parasites or cuckoo bees that do not build their own nests. Instead, They depend on the nest and pollen their hosts collect to feed their offspring.
People often confuse them with wasps because of their similar appearance. Their bright coloring acts as a warning protection against predators. They are always close to their host´s nests preying on their offspring, their food supply and often on the host itself.
Mining bees (Andrena species)
Mining bees can range from 4-17mm long in size and nest in the ground. Although mining bees are polylectic, they only feed on shallow flowers, like daisies or Asteraceae because of their short pointed tongues. They collect pollen on their hind legs and can be recognized by grooves (facial fovea) that run down the inside of their eyes .
Mining bees are typically active between April and June. Mating takes place in early spring. Male mining bees are fortunate to mate several times unlike honey bee drones. However, the price they pay for the pleasure is the same – death! The fertilized females dig up the soil, excavating up to 3 shafts, each with up to 5 smaller nesting chambers.
Tawny Mining Bee (Andrena fulva)
The orange colored tawny mining bee (ca. 1.2 cm or 0.47 inches) is fairly common in Europe and is active from around March to June. Their typical habitat includes towns, gardens, grass- and farmlands, as well as heath- and moorlands. The nests, made in short turf or lawns, look like small volcanos with the entrance hole in the middle of the crater.
It is not easy to identify the tawny mining bee from other mining bees. The females hair is much denser than that of their smaller male counterparts. Males can be identified by their white tufts of hairs covering their face.
They are active from April to June, about the same time as cherry, pear and apple trees blossom. The female collects pollen and nectar for the larvae, which develop underground (each in a single ‘cell’ of the nest) and hibernate as pupa over winter.
Early mining bees (Andrena haemorrhoa)
Early mining bees are spring bees common in Europe, and are active from early April to the end of June, beginning of July.
Measuring about 8 to 11 mm (0.31 – 0.43 inches), the early mining bee thorax is reddish brown on the top that changes into a black abdomen and finishes with a reddish brown rear end. The females are much larger than the males that have lighter hair, which tends to be grey to white.
Their habitat and nesting sites can be found in gardens, playgrounds, sports fields, paths and the sides of roads.
Ashy or Grey Mining Bee (Andrena cineraria)
The Ashy mining bee (Andrena cineraria) commonly nests in sandy banks and has a single flight period each year. It is most active from early April until early June when fruit trees are blossoming but has been seen as late as early August. The males emerge well before the females.
Females can be identified by their black color with two broad ashy-grey hair bands across their thorax and white hairs on their front femora. Male ashy bees, although similar, have their entire thorax covered in less dense grey hairs, with a very pronounced tuft of white hairs on the lower face and white hairs on all femora.
Wool carder bee (Anthidium maculatum)
Wool carder bees are polylectic and belong to the family of Leaf Cutter Bees or mason bees. They are native to North Africa, Asia, and Europe but are also seen in North America and parts of South America. Untypical in bees, the females of this species are significantly smaller than their male counterparts, measuring 11–13 mm (0.43 – 0.51¨) compared to 14 – 17 mm or 0.55 – 0.67¨.
Wool carder bees are black and covered with yellow-grey hairs. Males and females have a similar color pattern with their faces and abdomen covered in yellow spots. While females have almost completely black legs with very small yellow spots, males legs are shades of yellow covered with grey hairs.
Having larger males than females is not the only peculiarity of this remarkable species. The name ´carder´ stems from their behavior of scraping hair from leaves, collecting resin, plant fibers and earth they mix together to build their nests. The females roll the threads into woolen ball that stick to the hairs on the underside of their abdomen. Another unusual trait of these bees is that female offspring emerges before their male counterparts.
The mating process of the wool carder bee is different to most other bees. Males of this species are highly aggressive. They claim patches of flowers, which they patrol and defend by attacking almost anyone that enters. Unlike other bees the male does not leave his territory for mating. He waits for a female to forage in his patch so he can mate with her. Both, males and females mate with various partners throughout their productive life.
Flower bees (Anthophora species)
Flower bees look similar to bumblebees and often get mistaken for them. They have long tongues to access the pollen from deep flowers, which they carry back to their nests on their hind tibia.
Leafcutter bees (Megachile species)
Leafcutter bees are not one, but over 1500 species belonging to more than 50 subspecies. They originate in Europe and have been introduced to various regions worldwide, including North America. One species, the alfalfa leafcutter bee (Megachile rotundata) is very effective in pollinating crops in different parts of the world. These include alfalfa, carrots, other vegetables and some fruits.
Leafcutter bees belong to the family of cavity nesting bees and do not store honey. Their name is derived from their action of cutting circular discs from leaves or petals, which they use to line their nests. To build just one cell, a bee needs to cut around 40 discs. Like other solitary bees, they lay an egg into a cell together with food consisting of nectar and pollen, seal the nest and then abandon it.
The females of the Megachile species collect pollen using the underside of their abdomen that is covered in scopal hair which curve towards the tail. Males emerge earlier than females and are generally smaller in size. As with most males, they die shortly after mating. Females live a few weeks longer, during which time they build new nests.
These species can be attracted to your garden by providing a bee hotel.
Hairy footed flower bee (Anthophora plumipes)
The small (1.4 to 1.6 cm/0.55 – 0.63 ¨) hairy footed flower bee is a common species found in most of Asia, Europe, the United States, and North Africa. Their typical habitat includes coastal areas, woodlands, towns, roadside verges, and gardens.
The males and females of this species look completely different. The sandy-colored males emerge from their hibernation a couple of weeks before the totally black, furry females that resemble black bumble bees. Males can be identified by their orange-brown colored long body hair that also covers their middle legs and feet.
Appearing from late February, beginning of Marc until June, they can be observed as they fly rapidly, hovering around plants. Their long tongue allows them to access nectar from cowslips and pulmonaria plant species, which makes them important pollinators for early spring flowers.
Females often make their nest in walls in the soft mortar but sometimes also in soil.
Blue Carpenter Bee (Ceratina Cyanea)
Halictidae, the second-largest family of bees is commonly seen worldwide. They are called sweat bees because they are attracted to perspiration but only sting when disturbed.
Halictidae come in various colors, from dark-colored and often metallic in appearance to partly or completely green, or red. Some species, particularly the males, have yellow markings and faces.
They can be identified by their strongly curved basal vein on their wing. Their short tongues are pointed, which makes them better adapted to collect pollen from shallow or short flowers. The Halictidae species collects pollen on the underside of their abdomen and on their legs.
Most bees of this species nest in the ground, although a few also make their nests in wood. Halictidae are generally solitary or primitively eusocial in behavior. This means, like honey bees, they live in cooperative groups where usually one female and several males reproduce. Non-breeding individuals care and protect the young and provide for them.
Lasioglossum sweat bees consists of more than 1700 species, making it the largest of all bee species. They differ in size, color and build, but also in other characteristics. Some are parasite bees, some nocturnal, others are oligolectic, i.e. they only collect pollen from a single family or genus of flowering plants.
The majority of Lasioglossum bees are mining bees that make their nests in the ground, although some also make their nests in rotten logs. Their nesting behavior is just as varied as their looks. Some species are solitary bees, while others display primitive eusociality or social parasitism.
Just as their nesting preferences vary, so does their colony size, which can range from small colonies with one single queen and four or less workers to large colonies with more than 400 workers. Their life cycle is perennial.