Wasps tend to turn their attention to satisfying their urge for anything sweet at this time of year and in my garden the red-hot pokers (Kniphofia spp.) are proving irrestistible to them. Red-hot pokers are pollinated by sunbirds in their native South Africa and to satisfy these birds' energy needs they secrete large volumes of nectar. Wasps (Vespula vulgaris) are so desperate to reach it that they even try to get at the nectar in the unopened florets, as this one is doing, by chewing through the flower's corolla - you can see where it's already tried to chew a hole in the floret immediately above it, then gave up and having a go at this one instead.
As soon as the florets at the bottom of the inflorescence open the wasps force their way into the narrow tube, which evolved to accommodate a sunbird's slender, curved beak. The wasps have to bend their forelegs backwards to reach the drops of nectar at the top of the tube (you can see the foreleg bent back, just above the wing, in this photo). It's even more of a struggle for them to get out.