Kobe University plant biologist Suetsugu Kenji, a professional on these orchids, discovered that a particular species of this genus, Gastrodia foetida, has especially fleshy petals that fall and decompose off a few days after pollination. He decided to investigate these plants in the look for the very first example of orchids taking part in “nursery pollination”, which is a plant offering a breeding place to its pollinator.
A fruit fly lays its eggs inside a flower of Gastrodia foetida. Credit: Suetsugu Kenji
And certainly, in the study now published in the journal Ecology, he reports that fruit flies frequently lay their eggs into the plants flowers which their larvae can totally develop into adult flies in this environment.
Suetsugu states: “The most interesting aspect is that contrary to its common name as the fruit fly, Drosophila bizonata, a species focused on mushroom-feeding, primarily uses decomposing Gastrodia foetida flowers as brood sites. A possible description is the truth that Gastrodia foetida is a non-photosynthetic orchid that eats fungis. These non-photosynthetic orchids often exhibit chemical similarity to the fungi they take in, highlighting the olden saying You are what you eat. As a plant that eats mushrooms, G. foetida most likely tastes similar to a mushroom, making it a prime target for the mushroom-specialized fruit fly.” This discovery is considerable since it discovers a brand-new kind of nursery pollination system, surpassing deceptive techniques frequently discovered in the genus.
Flower of Gastrodia foetida. Credit: Suetsugu Kenji
The Kobe University scientist further describes that the relationship is neither required nor particular, that is, the fruit flies also lay completely establishing eggs on fungi. Therefore, this finding might represent an example of the shift from a deceptive relationship towards mutualistic symbiosis, suggested by two factors: the low expense to the plant, considering that the petals are not required any longer after pollination; which carefully associated Gastrodia dominantly utilize a deceptive strategy without supplying a nursery.
A flower of Gastrodia foetida on the verge of decay. Credit: Suetsugu Kenji
Suetsugu concludes: “This study represents the first evidence of nursery pollination in orchids, comprising almost 30,000 types, and being the most diverse plant group in the world. In addition, it contributes a crucial understanding of the complex and mutually advantageous relationships that can develop in nature. The understanding of how plants can offer authentic advantages instead of merely deceiving pollinators could affect the more comprehensive study of plant-animal interactions and their evolutionary dynamics.”
Reference: “A novel nursery pollination system in between a mycoheterotrophic orchid and mushroom-feeding flies” by Kenji Suetsugu, 23 August 2023, Ecology.DOI: 10.1002/ ecy.4152.
The research study was funded by the Japan Science and Technology Agency.
The mutualistic relationship in between Gastrodia foetida and its pollinator, both of which primarily feed upon mushrooms. The flowers give off a mushroom-like smell that tempts the flies in. As the flies feed on the flowers, pollen grains connect to their backs (1 ). When the fly leaves one flower and gos to another to lay eggs, the connected pollen enters contact with the preconception, finishing pollination (2 ). After effective pollination, the flower starts to decay and internally hatched larvae begin consuming the petals (3 ). The larvae grow further by taking in the petals that have actually fallen to the ground (4 ). Roughly one week later, they emerge as grownups. Credit: ANSAI Shun
For the very first time, orchids that consume fungi have been observed providing their flowers to fungi-eating fruit flies in return for pollination services. This discovery represents the very first evidence of nursery pollination in orchids. This unique brand-new plant-animal relationship hints at an evolutionary transition towards mutualistic symbiosis.
Orchids are well understood to trick their pollinators into going to the flowers by imitating food sources, breeding premises, or even mates without in fact offering anything in return. The fungi-eating, non-photosynthetic orchid genus Gastrodia is no various: To attract fruit flies (Drosophila spp.), the plants typically emit an odor like their typical diet of fermented fruits or rotting mushrooms.
A fruit fly larva consuming breaking down floral tissue on the ground. Credit: Suetsugu Kenji
The fruit flies get enticed into the flowers, are caught there for a brief while, and get pollen connected to their backs which they then carry to other plants of the same species. Therefore, this deceptive relationship offers benefits to only one partner.
The flowers produce a mushroom-like smell that draws the flies in. As the flies feed on the flowers, pollen grains connect to their backs (1 ). When the fly leaves one flower and visits another to lay eggs, the attached pollen comes into contact with the stigma, completing pollination (2 ). For the very first time, orchids that take in fungi have been observed using their flowers to fungi-eating fruit flies in return for pollination services. Suetsugu says: “The most intriguing element is that contrary to its common name as the fruit fly, Drosophila bizonata, a species specialized in mushroom-feeding, primarily makes use of decaying Gastrodia foetida flowers as brood sites.
