This was taken in the BYG, where there is a small patch of mountain mint. This plant attracts a huge variety of insects and in particular these large and striking wasps. They look fierce but they are not aggressive, unless you happen to brush them away from feeding when they might not be very happy, and who can blame them. These guys hunt grasshoppers and take them down to their burrow where they stock them for their larvae to feed on (the adults are happy to feed mostly on nectar). I have seen them swooping into their burrows with huge grasshoppers clasped beneath their body, an impressive sight, though I really feel sorry for the grasshoppers.