Introduction There are more species of bee than birds and mammals combined. With at least 20,000 described species and with many new species being described annually, bees comprise a major component of our planet's biodiversity. They play a vital role in human ecology, a fact underlined by the estimate that every third mouthful of our food is dependent on the pollination services of bees. Honeybees are the most intensively studied of all insects. Together with bumblebees and stingless bees, they are highly social. Such bees, though, account for only a very small proportion of the world's bee fauna. The vast majority of species, more than 90 percent, are solitary or non-social. Here, each nest is the work of a single female working alone; there is no caste of workers as in the highly social bees. Nevertheless, most people are familiar with the social honeybees and bumblebees...but are they really? In television news items stock footage of bumblebees at flowers is used to illustrate pieces on colony collapse disorder in honeybees and, to even things up, footage of honeybees illustrates pieces on concern about declining populations of bumblebees. To add to the confusion, the iconography of labels on jars of honey often includes caricatures of bumblebees flying around a rustic-looking beehive! Being social and making honey are in reality eccentric things for bees to be engaged in; the focus on social bees means that the vast majority of bees barely appear on the radar of public consciousness. One of the aims of this book, therefore, is to give due attention to the highly social bees and their importance in human affairs, but also to reset the balance and open up the solitary bees to a wider audience. These bees are highly diverse in terms of their nesting and mating behavior and their relationships with flowering plants. In its broadest sense, biodiversity and its maintenance are now well and truly on the public agenda and, thanks to high quality natural history television documentaries, most of us are broadly familiar with the ecology of big game species in Africa. Only now, though, are we beginning to unravel the ecology of the little game, the insects, whose ecological services support and maintain habitats and ecosystems. They do this via complex webs of interactions between themselves, plants and other organisms. These webs form a dynamic, self-sustaining safety net on which we depend and bees occupy keystone positions here. There is no doubt that visiting aliens from another galaxy would quickly realize that insects are the dominant terrestrial life forms on our planet rather than our own species. This is important: our antecedents evolved in response to the opportunities and challenges presented by the savannahs of East Africa and they did so by courtesy of the ecological services provided by insects, including the bees, which continue to play vital roles in human ecology. When early man migrated out of Africa, the habitats he encountered may have been different from those in Africa and the bees and plants were certainly different; nevertheless, the habitats he colonized were created and maintained by the same co-evolved, life-sustaining webs of bee-plant relationships. It was only as late as the 18th century that people began to understand and value the pollination services of bees. This knowledge grew and developed in Britain and Europe and led to beehives being placed in fruit orchards specifically for pollination purposes and growers began to enjoy higher fruit yields. Today, in the United States, bees pollinate 130 crop species and worldwide more than 400 crops. Most of this managed pollination is by honeybees and the value of these crops greatly exceeds the value of honey produced. Honeybees, however, are now under increasing pressure from disease, parasites and the sinister colony collapse disorder. In the period 2009-2010, beekeepers in the United States lost on average 42.2 percent of their colonies and in the last 10-15 years, both the United States and Britain have lost nearly 50 percent of beekeepers, who have given up the craft. For too long we have relied on this single species as a managed pollinator. If we are to recruit additional species, then we need to know more about the world's bees. Leafcutter bees ( Megachile spp.) and mason bees ( Osmia spp.) are some of the main contenders as alternative pollinators. The Alfalfa Leafcutter bee ( Megachile rotundata ) is managed on a large scale in Canada and the United States for pollination of alfalfa, an important forage crop for cattle. Bumblebees are now widely used in Britain, Europe and increasingly in the United States as pollinators of glasshouse crops, especially tomatoes and I have been involved in developing the management of the Eurasian Red Mason bee, Osmia rufa as an orchard pollinator and the Blue Orchard bee, O. lignaria , as a farmed pollinator of almonds in California and both species show great potential. Many of our wild bee faunas, however, are already under threat from a variety of human activities, including increasing urbanization and the over-fragmentation of natural habitats, not to mention the reduced floral diversity associated with intensive agriculture. In the tropics, vast tracts of rain forest are being lost by logging and the ever-expanding palm oil industry. As E. O. Wilson, the great ant specialist and naturalist has put it, we run the risk of losing the book of life before we have finished reading the introduction. Even where these bees are not actively managed, they still, in their "wild" state, make a valuable contribution to crop pollination. The vital role of bees in human ecology is underlined by the fact that much of the estimated third of human food dependent on bee pollination can be attributed to solitary bees. The association of bees and man has thus been long and close. For me, it began as a 12 year-old, in the coastal sand dunes 24km (15 miles) north of Liverpool. It was here that I made my first discoveries about bees. Even now, as a full-grown man, give me a flower-rich meadow and a variety of pollen-plundering bees and I am as happy and excited as that boy in the Lancashire dunes. And there is much to be excited about. Bees have an impressive diversity of size, form and nesting behavior. They can be found in high, alpine and sub-arctic regions, rainforest, savannahs, steppes and deserts. The greatest diversity of species occurs in shrub communities in regions with a Mediterranean type climate: short, mild winters, warm springs and hot, dry summers. Many species excavate nests in the ground, others construct exposed nests on rocks or vegetation while others nest in pre-existing cavities such as hollow plant stems, beetle borings in dead wood; some specialists use snail shells. Specialization is a theme running through this book--specialization in the nesting and foraging behavior of females and in the mate seeking behavior of males: all of the classic behaviors recorded in birds and mammals--scramble competition, lek displays and aggressive territoriality are also found among male bees. We need bees, not only for the pollination of food crops, but also for the keystone roles they play in maintaining ecosystems and habitats, including many to which we accord aesthetic and recreational value. Understanding the diversity of bees and their network of relationships with flowering plants is basic to any attempts to conserve many major habitats. Central to these challenges are considerations such as the size of, and distance between, fragmented reserves of natural habitat relative to the foraging distances of the bees that pollinate their floral components. Do we know enough about this when designating tracts of land for reserves? This book will illustrate this diversity with potent examples, together with case studies of some bizarre networks of bee-plant relationships. These will include the vital roles bees play in Excerpted from Bees: A Natural History by Christopher O'Toole All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.
