A species of seed - feeding fly sheet is critically damaging the semen production of multiple orchid coinage , as revealed by a group of Japanese researchers . If the damage because of this fly sheet is occurring long - full term and across Japan , these already - peril orchid metal money could become unable to regurgitate using seeded player , and their dwindling identification number will take a large smasher .

The resume was carried out by Project Associate Professor Kenji Suetsugu ( Kobe University Graduate School of Science ) , Shigeki Fukushima ( Head of the Chiba Prefectural Agriculture and Forestry Research Center ) and Masahiro Sueyoshi ( Principal Investigator at the Forestry and Forest Products Research Institute ) . The finding were publish on September 21 in the online edition of Ecology .

Figure 1 : The Golden Orchid bloom of youth ( left ) and J. tokunagai on the flower ( Photos by Takuto Shitara )

With over 20,000 metal money classified , orchid are one of the most diverse group of flowering plants , and the unique shape of their blossom has entranced people for many years . Unfortunately this popularity has go to orchid over - harvesting . Combined with deprivation of home ground make by maturation , this means that over 70 % of Japan ’s native orchid species are classified as endanger by the Ministry of the Environment .

From the perspective of genetic diversity , it is honorable for endangered mintage to reproduce via seeds rather than clone . This means that to save these orchid , we should discover the insect that pollinate these plants and the parasites that prevent semen - based procreation . Therefore , Professor Suetsugu ’s research team has been collecting information on organism related to orchid reproduction .

During a survey to identify the pollinators of orchidaceous plant species , the team found that in pollinated fruit which should be able-bodied to get seeds under normal condition , a seed - feeding fly known as Japanagromyza tokunagai was destroying the seeds of multiple orchid specie ( see figure 1 ) .

Figure 2 : At a glance this fruit looks healthy , but it has been overrun by J. tokunagai . The dark-brown country indicated by the pointer is fly pupae . When the fruit is dissected , we can see that there are no seeds left .

When orchids blush , J. tokunagai lays its ball in the young fruit , and the dirt ball young grow up eating the seeds in the fruit . They become pupae inside the yield , and when they incubate into their wing bod they make a hole in the fruit so as to make their exit . Fruit that is parasitized by these flies arise to the same size as normal fruit , so at a glance it look healthy . This mean that we have likely undervalue the impairment do by these flies . In many causa , fruit parasitized by the tent-fly produces no seeds at all ( see figure 2 ) . humanity have know about the harm triggered by ejaculate - feeding fly front since the 1980s , but we do not know the impact on source product in concrete terminal figure .

In this subject field , after artificially cross-pollinate five species of orchids in Japan ’s Kanto realm , the squad cover some specimen with bags to prevent the J. tokunagai from inscribe , and left others uncover . Afterwards they compared the quality and amount of the seeds produce by each plant . This is the first subject field to precisely quantify the reduction to orchid seed yield due to J. tokunagai . effect showed that in all five coinage , damage cause by J. tokunagai reduced seed production by over 95 % . It is not yet clear whether this is come about across Japan or over an extended prison term period . However , if this situation continues , the touched orchid metal money will become unable to reproduce via seed production , threatening their already dwindling numbers .

It is also possible that equipment casualty because of J. tokunagai may be intensifying in recent years . This could be for two reason : firstly , the flies are non - aboriginal species that have been introduced into areas where they miss natural enemies , and secondly , because the orchid universe have become fragmentise , also reducing the population size of it of innate enemies .

seed : Kobe University