The Sterile Appendix Underpins High Pollinator Specificity in Arisaema with a Lethal Kettle Trap Pollination System

Photo 1: The uniquely shaped Arisaema inflorescences (A. angustatum [left] and A. peninsulae [right]) that are reminiscent of carnivorous pitcher plants. However, unlike pitcher plants that absorb nutrients from captured insects, Arisaema inflorescences trap insects for successful pollination. Photo credit: Takayuki Shimizu. Photo 2: Fungus gnats trapped within female inflorescences of Arisaema angustatum and A. peninsulae showcasing the marked difference in pollinator composition. Brevicornu sp.1 (left) trapped by A. peninsulae and Cordyla murina (right) trapped by A. angustatum. Bar = 1 mm. Photo credit: Rikuo Sato. Photo 3: The upper part of an Arisaema inflorescence (A. angustatum [left] and A. peninsulae [right]). When we removed the sterile appendix (indicated by the arrow), the number of visitations by principal pollinators significantly decreased. Our results indicate that the appendix underlies high pollinator specificity in Arisaema. Photo credit: Takayuki Shimizu. These photographs illustrate the article “The sterile appendix of two sympatric Arisaema species lures each specific pollinator into deadly trap flowers” by Kenji Suetsugu, Rikuo Sato, Satoshi Kakishima, Yudai Okuyama, and Masahiro Sueyoshi published in Ecology. https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.3242