I've posted previously about bumblebees apparently supping on cornflower (Centaurea) flowerbuds, before they were open - this is known as nectar robbing, and we saw it earlier in the season on a wide variety of plants, including Geraniums and Aquilegias. A bee will bite through the fabric of a flower bud (petal, sepal, or whatever is in the way) to get a meal at the nectaries that lay hidden inside. This will happen on flowers which are still closed, and also on those that have a trumpet longer than that bee's tongue. In the fullness of time, those flowers will open, and then you will see the evidence of crimes past - here, the holes around the edge of a bindweed flower - that were made while the flower was still curled up, and the petals folded together.
|Bindweed flower, showing evidence of nectar-robbing|
|Leaf-cutter holes in beech leaves|