 Like their relatives the honeybees , bumblebees feed on nectar , using their long hairy tongues to lap up the liquid ; the proboscis is folded under the head during flight . Bumblebees gather nectar to add to the stores in the nest , and pollen to feed their young . They forage using colour and spatial relationships to identify flowers to feed from . Some bumblebees rob nectar , making a hole near the base of a flower to access the nectar while avoiding pollen transfer . Bumblebees are important agricultural pollinators , so their decline in Europe , North America , and Asia is a cause for concern . The decline has been caused by habitat loss , the mechanisation of agriculture , and pesticides . 
