A detailed and up-to-date account of the behaviour and ecology of bumblebees. This group of relatively large, colourful and familiar insects are a very popular subject of study because their behaviour can be observed without the use of elaborate equipment, enabling amateur and experienced entomologists alike to get close to these colourful and social creatures. Unlike honey bees, bumblebees work on plants with no nectar, and play a crucial role in the pollination of flowers and vegetables. The farming industry relies heavily on these efficient pollinators: few, if any bean flowers, for example, would set pods unless they were pollinated by bumblebees, and many apple, pear and plum trees rely on visits for a bountiful harvest. However, bumblebee populations have recently suffered alarming decline, with three of the UK populations already extinct and another nine on the endangered species list.