Getting inside the flower of Bottle Gentian or Closed Gentian (Gentiana clausa), one of our latest flowering plants, in order to collect nectar and pollen is a monumental task that few insects, other than fairly large species of bumble bees, attempt. The petals are closed so tightly it takes even bumblebees several seconds of pushing, shoving and cramming to push the petals aside and get through the miniscule opening at the top of the blossom.
Pollen is the primary bumblebee attractant, as the sugar concentration of Bottle Gentian’s nectar is fairly low. Some bumble bees take a short cut – they chew a hole to gain access to the reproductive parts of the flower. The hole is often two-thirds of the way up the blossom, directly opposite the pollen-laden anthers within the flower. Look closely at the hole in the lefthand blossom in the photograph and the adjacent, dissected blossom, and you will see that the bee’s aim was dead on. You can even detect a portion of the anther through the hole.