Like other bumblebees, the whole colony works together to provide food and a cosy home for the growing young. These colonies form in spring and by this time of year they'll have grown to capacity. Rather than keep producing female worker bees, who do the hard work of foraging for pollen to feed to the larvae, the nest begins to produce males and the next generation of queens. This is likely to be the moment when you notice them as males begin to congregate outside the nest entrances awaiting the appearance of the new queens. The new queens are the only members of the colony that will survive the winter so males are desperate to ensure that it's their genes that are passed on to next year's generation.

Bumblebees are generally docile little creatures that bumble about their business with seemingly no worries or cares. If they feel that their home is being threatened, however, they may sometimes become a little more aggressive so if you've got three bumblebees nesting in a cavity in the shed roof, for example, make sure that you gently close the door rather than slam it and perhaps quietly observe a nest from a little distance. It's only the females that have the ability to sting, though, so when you see a cloud of males waiting for the emergence of a queen there's no need to panic.

Bees and other insects have been having a hard time recently and gardens and greenspaces can make a huge difference. Making sure that you've got flowers blooming for as long as possible throughout the year will really give them a boost - from the early emergers in spring to the hangers-on in autumn. In mild winters we're even starting to see some buff-tailed bumblebees out foraging to keep a late colony going through the whole year - plants like heathers, mahonia and hellebores can really help these determined insects.