Repeated evolution of flowers specialized for buzz pollination

If you’ve ever looked closely at a tomato flower, you might have noticed that its anthers cluster together in the center of the flower, making the pollen inaccessible to most insects. Tomato flowers are an example of a buzz pollinated flower, in which the pollen is released by the physical shaking by a pollinator (usually but not always a bee), and the pollen falls through a small pore where it is collected by the bee (check out this YouTube video to see it in action). Tomato flowers are a type of poricidal flowers, not all of which are buzz pollinated, but which share the characteristic of having a small pore though which pollen is released. Poricidal flowers are found throughout the angiosperms, so Russel et al. decided to look at their phylogenetic distribution and evolutionary origins. They found that about 10% of angiosperm species in at least 639 genera have the poricidal morphology, and that this morphology has at least 205 distinct evolutionary origins. The trait may be beneficial in some environments (e.g., arid and with low wind) but it has the disadvantage of being more dependent on specific pollinators. Based on their phylogenetic data, the authors conclude that the transition to poricidal morphology is rare, but the probability of losing it is high. As yet the developmental programs underpinning this fascinating evolutionary convergence remain to be identified. And, watching a bee quiver and shake to capture some pollen is a great way to get people interested in plant science! (Summary by Mary Williams @PlantTeaching.bsky.social) Evolution 10.1093/evolut/qpaf220.