Bees & Wild Bees
Nature typically knows best. Humanity has ever since acknowledged this fact and both investigated and copied or exploited the efficient solutions and complex systems of dynamic co-operation nature came up with, mostly with the aim to improve own procedures. Hence, we are well aware that honeybees are important and useful creatures, and we have long been utilizing this knowledge to multiply our crops and satisfy our honey cravings. In the shadow of the honeybee’s fame, the wild bee has been ignored and underestimated for a long time  – unjustifiably so, as this chapter might demonstrate. Now that our environmental conscience is slowly changing and all our native bees are facing increasing challenges, it may be the right time to promote the honeybee’s wild relative.
Unless stated otherwise, all bee-facts and background information presented in the following sections originate from Antonia Zurbuchen and Andreas Müller’s book Wildbienenschutz – von der Wissenschaft zur Praxis (2012)  and from Paul Westrich’s book Wildbienen – Die anderen Bienen (2015) .
Bees, Wild Bees and the ‘Pollination Crisis’
The Western Honeybee (Apis mellifera) is presumed to be the most important pollinator of wild and cultivated plants. Its colonies, which can embody up to several tens of thousands working bees, fly from early spring to late autumn. Each colony can collect up to 180 kilograms of nectar and 30 kilograms of pollen per year in a radius of more than 10 kilometers around the hive. The bee population is facing many different problems, however, leading to increasing risks for nature and our food production. As Klein et al. point out, this situation, which is often referred to as the ‘Pollination Crisis’, exposes “the potential risk of our sole reliance on honeybees for agricultural pollination” [4, p. 304].
However, other than many might think, the honeybee is only one of many different species of bees, most of which are very efficient pollinators as well. In Germany alone, there are about 550 other bee species besides the Western Honeybee, and it is said that there are around 2.100 different kinds of bees in Europe and more than 17.000 different bee species worldwide [3, p. 7]. These ‘other’ bees besides the honeybee are usually called ‘wild bees’, highlighting the fact that they, other than their livestock relatives, remain wild, undomesticated species that still occur in the wild.
Depending on the region, weather and kind of plant, wild bees can be just as or much more efficient pollinators than the domesticated honeybee, or even be a plant’s sole capable pollinator. Yet, just like honeybees, wild bees face a range of problems that have led many of its kinds to the brink of extinction. However, while the endangerment of the livestock honeybee has been in the public spotlight for decades, the wild bee continues to be underestimated in its efficiency and importance for both wild and cultivated plants [2, p. 121]. Different studies have shown that honeybees cannot function as the sole pollinator for all plants, especially for those that require the bumblebee’s special pollen-freeing technique called ‘buzzing’ (a kind of vibrating), and that wild bees can be much more efficient in pollinating certain plants. For example, to pollinate an acre of apple trees, the service of the one or two colonies of honeybees required, each containing around 15.000 to 20.000 worker bees, can be replaced by the service of only 250 Blue Orchard Bee females (Osmia lignaria) .
Wild Bee Predicament
Rapid urbanization and large scale soil sealing has led to a massive decrease in diverse native flora and small scale structures, which are important for the wild bee’s different nourishing and nesting needs. In Central Europe, depending on country and region between 25 and 68 percent of all wild bee species are currently enlisted on the Red List of endangered species [2, p. 17]. Each one of the many different wild bee species has specific characteristics in looks, active season and mating strategies, as well as varying requirements for nesting and food sources. Ranging in size from 3 to 30 millimeters in length, most wild bees, apart from the more social Bumblebees (Bombus) and some kinds of Sweat Bees (Lasioglossum), live solitary and only fly at very specific times of the year.
Being high in protein, plant pollen is the most important food for bee larvae and adult bees, alongside nectar and, for some species, plant oil. Depending on the kind of wild bee, the female needs to fly between nest and plant for 2 to 50 times and visit dozens to a few hundreds of flowers to collect enough pollen for just one offspring. Honeybees are all-rounders when it comes to the collection of pollen, but wild bees can be more complicated. While some wild bees collect the pollen of a few to many different kinds of plants (pollen generalists), others are restricted to only one plant family or kind (pollen specialists). Especially the propagation of big monocultures for agriculture as well as the increased use of chemical fertilizer, which leads to a predominance of highly competitive plants at the expense of native plants that adapted to more nutrient-poor soils, has led to a big change in environments that came along with a massive decrease in variation of native flowering plants [2, p. 17]. Naturally, this turns out to be a big problem especially for highly specialized bees that cannot find enough sources for pollen in their natural habitats anymore.
Most wild bees live solitary, meaning that their females build and victual their nests alone, without the help of conspecifics. The female bee generally builds brood cells in specific structures that she fills with pollen and nectar or flower oil as a food supply for her offspring within an active period of four to six weeks [3, p. 21]. On this nugget of supplies she places one egg before she closes the cell. As diverse as the bees’ looks, behaviors and plant preferences can be, as different are their nesting requirements. Depending on the kind of bee, wild bee nests can be found in the ground, in dead wood, in empty snail shells, old plant galls or plant stems, on rocks or tree trunks as well as in holes and tunnels left by wood worm beetles or horntails [3, p. 49]. Bees that nest in the ground or in dead wood usually burrow vertical or horizontal tunnels by themselves. Around one fourth of all Central European kinds of wild bees, so called cuckoo-bees, do not build their own nests but act as cleptoparasites, secretly placing their eggs in the nests of certain other bee species.
Due to the loss of natural nesting structures in the process of continuous restructuring and clearance of our landscapes for agriculture and urban development, wild bees often cannot find suitable locations for their nests in proximity to their needed plants anymore [2, p. 15]. Growing areas of sealed soil have led to an especially difficult situation for ground nesting bees that nowadays can barely find any more unused vertical or horizontal patches of loose sand or loam [6, p. 15]. While attempts to offer nesting aids, usually in form of so-called insect hotels, can be successful and help maintain the wild bee population in an area, many of the commercially available structures are of poor quality, contain useless elements or are placed too far from suitable plants and therefore remain empty [6, p. 10].
Nonetheless, since bees generally are not easily disturbed by human noise and presence [2, p. 115], urban areas with suitable conditions can host many different kinds of wild bees. The microclimate of towns and cities tends to be warmer and dryer, a climate that bees prefer, and urban areas have the potential to provide a high density of different native flowering plants and small structures in gardens, parks and on balconies. Solitary bees do not have to defend a colony, so they tend to be very peaceful and almost never defend their offspring against anything other than insects their size, making them harmless cohabitants in human proximity [3, p. 161]. Unless directly threatened by touch, wild bees do not sting humans. However, it should be emphasized that wild bees are no pets, even when nesting on private properties or in manmade nesting aids [6, p. 14]. Moreover, being endangered species, all kinds of wild bees are considered highly protected animals in Germany according to the Bundesartenschutzverordnung (Protection of Species Order) [3, p. 75]. According to § 44 of the German Federal Act for the Protection of Nature (‘Bundesnaturschutzgesetz’) it is forbidden to prey, capture, injure or kill protected species or to remove, damage or destroy their forms of development, their nests and their resting places .
The greatest variety of flowering plants in gardens and the best nesting aids cannot replace official protective measures in nature, especially because many, foremost ground-nesting bees cannot make use of regular manmade nesting aids other than loose brick walls or paths, or spots of free, loose soil in gardens. Nonetheless, in order to promote and press official, large-scale protective measures, it is important to raise awareness of the wild bee’s precarious situation. Nesting aids and the right kinds of plants in proximity to the anthroposphere can create opportunities to observe and involve with wild bees, which can be an important first step to raise awareness [3, p. 75]. After all, compared to honeybees, wild bees have a great disadvantage in the battle for human attention: They do not produce honey and usually no beeswax, restricting their potential offer to humans in return for protection to the often forgotten, but highly important, act of pollinating the plants that provide us with food and recreation.
 REISSMAN, H. We need to save the (weird) bees, 2 December 2016. Retrieved from: https://tedxinnovations.ted.com/2016/12/02/we-need-to-save-the-weird-bees. Accessed on: 8 April 2017.
 ZURBUCHEN, A.; MÜLLER, A. Wildbienenschutz - von der Wissenschaft zur Praxis. Bern; Stuttgart; Wien: Haupt, 2012.
 WESTRICH, P. Wildbienen - Die anderen Bienen. München: Verlag Dr. Friedrich Pfeil, 2015.
 KLEIN, A. M. et al. Importance of pollinators in changing landscapes for world crops. Proceedings of the Royal Society of London B: Biological Sciences, 274(1608), 2007. 303-313.
 BUZZABOUTBEES. Why Do Wild Bees Matter? Retrieved from: www.buzzaboutbees.net/wildbees. html. Accessed on: 24 January 2017.
 DAVID, W. Fertig zum Einzug: Nisthilfen für Wildbienen. Darmstadt: pala-verlag, 2016.
 GESETZE IM INTERNET. Gesetz über Naturschutz und Landschaftspflege (Bundesnaturschutzgesetz - BNatSchG). § 44 Vorschriften für besonders geschützte und bestimmte andere Tier- und Pflanzenarten. Retrieved from: www.gesetze-im-internet.de/bnatschg_2009/__44.html. Accessed on: 24 January 2017.