Insects with ‘double hats’ solve a botanical mystery

Dec. 5 () –

Scientists from Kobe University have described a unique case in which the same species of insects They pollinate a plant and distribute its seedssolving a botanical mystery.

In the dark, humid undergrowth of the subtropical forests of the island of Shimoshima in Japan they grow parasitic plants that feed on the roots of other plants. They are called Balanophora, and for more than a century, the mechanism of their seed dispersal has been a mystery. It has been suggested that the tiny seeds are blown by the wind, but in the understory of (sub)tropical forests there is little or no wind. Some species of plants among the Balanophora are bright red, similar to strawberries, and attract birds and rabbits to eat them and thus disperse the seeds. However, others, such as Balanophora subcupularis, have dull colors and a yeasty odor, making vertebrate involvement unlikely. The pollination mechanism of the plant has also not been clear.

Kobe University botanist SUETSUGU Kenji specializes in understanding the interactions between these parasitic plants and their surrounding ecosystems, including the crucial but often overlooked role of invertebrate pollinators and seed dispersers. To find out who helps B. subcupularis reproduce, he and his team observed the plants for more than 100 hours and took tens of thousands of automated night photographs while the flower was in bloom or bearing fruit, identifying visitors. Additionally, they conducted animal exclusion experiments and seed feeding experiments to determine whether the animals in the photographs are indeed effective pollinators and seed dispersers.

In two consecutive articles published in the journal Ecology, the Kobe University team published that B. subcupularis is pollinated by ants and camel crickets, which visit plants in search of pollen and nectar. Surprisingly, These same species also later feed on the fleshy leaves that carry the seeds, which helps their dispersion. “It is well known that many plants depend on insects for pollination, although it is rare for ants and crickets to do so. In addition, many plants use birds and mammals to distribute their fruits, and again it is very unusual for crickets or other tiny arthropods take on this function. Even more surprising, it is very rare for the same animal to perform both functions, and it is unique for the same invertebrates to do so,” he says. in a statement Suetsugu about his surprise at this find.

The Kobe University botanist suggests that this rare combination of pollination and seed distribution functions may be influenced by two factors. First, “B. subcupularis blooms late in the year, when many typical pollinators, such as bees, are less active. Additionally, our study site is a small island at the northern end of the plant’s distribution, which could contribute to the scarcity of pollinators and seed dispersers.”

Suetsugu also highlights the broader implications of these findings: “This underlines the importance of invertebrates in plant reproduction and encourages us to further analyze how these relationships evolve and what environmental factors drive these unique adaptations. In more practical terms , our findings also contribute to conservation strategies for rare and endangered plants such as Balanophora subcupularis. Understanding their dependence on specific invertebrates for both pollination and seed dispersal helps guide conservation efforts. habitat and management of invertebrate populations, that are crucial for the survival of these plants.