Most pollinator-plant relationships follow the same trend – animal lands on plant, gets covered in pollen which it then transfers onto another plant of the same species – but there are many plants that go against the norm, and have a weird and wonderful method of ensuring that their pollen gets to where it needs to be.
Plants in the Araceae family, also known as ‘aroids’, act as a kind-of bed and breakfast for insects. These plants attract a wide range of insect pollinators by producing scents which vary between rotting flesh and sweet fruit, and many produce heat to help with the dispersal of their aroma. Most aroid species will trap any insect that comes into contact with its leaves inside a dungeon-like structure which it is unable to escape from. While the insect is trapped, the plant produces nectar to feed it and keep it alive and after 24 hours the male flowers mature and cover the insect with pollen. The dungeon then collapses and allows the pollen-covered insect to escape and find another aroid to pollinate, starting the process again!
Orchids are an extremely diverse plant group and their methods of attracting pollinators are variable between species. Most orchids just have one or two dedicated pollinators which can be bees, wasps, flies, ants or butterflies, and this means that if becomes extinct, the other will likely share the same fate.
Ophrys species have a very sneaky way of attracting male bees to their flowers. They have evolved their scent over time to mimic the pheromones released by a female bee and even have a similar appearance, which led to the designation of their common name – ‘bee orchids’. When a male picks up the scent, it lands on the flower of the bee orchid and repeatedly attempts copulation, all the while being covered in the plant’s pollen. Another type of orchid that encourages bee romance are bucket orchids, which produce a cologne for male bees that is irresistible to females.
Another orchid, Oncidium planilabre, has a less romantic approach to attracting male bees, and mimics a male rather than a female, which encourages attacks from male bees. When the male bee attacks the orchid, it is covered in pollen which is then transferred to the next bee-like flower that it takes a dislike to.
Another orchid with a strange pollination method is Holcoglossum amesianum. This amazing plant has the capacity to move its flowers 360 degrees to transfer pollen onto its stigma and does not rely on any external forces whatsoever.
Fig wasps and figs
Fig wasps and figs have a completely dependent symbiotic relationship. The fascinating pollination cycle of the fig tree begins when a female wasp enters one of the fruits through an extremely small opening, often losing its wings and antennae on its way in. Once inside, the female lays her eggs and dies shortly after. When the eggs have hatched, the male and female offspring have very different functions. The wingless males explore the inside of the fig, trying to find a female to mate with and once they have mated, they bore exit pathways to the outside of the fig then also die. The female offspring, once they have mated, collect pollen from the male flowers inside the fig and then use the pathways created by the males to escape. The females then search for a new fig fruit to pollinate and the whole cycle begins again.
Plants in the Axinaea genus have large, bulb-like structures on their stamens which entice passing birds. As the bird touches the structure with its bill, it explodes and covers the bird’s face with pollen. As the bird continues to forage, the pollen is transferred onto other plants.
Giant Amazon water lily
At the beginning of its pollination cycle, the giant Amazon water lily produces female flowers which have white petals and emit a strong fruity scent that attracts beetles. The flower itself is around 10 degrees Celsius warmer than the ambient temperature – another factor that makes it irresistible to beetles. When the beetles arrive and begin to feed on the nectar, the flower slowly closes and traps the beetles inside. Throughout the day the petals of the flower turn pink and it undergoes a sex change, turning into a male and covering the beetles in pollen. When the flower eventually reopens, it releases the pollen-covered beetles who are then free to continue their search for nectar.
Find out more about pollination and the slightly more ‘normal’ approach that most plants have on our new topic page.