Large Island Fruit Bats are the most threatened groups of bats worldwide. In insular settings, their decline has been hypothesized to result in the loss of important ecosystem services provided by these keystone pollinators and seed dispersers. The Nansei archipelago in Japan hosts one of the nation's two endemic fruit bats, the Ryukyu flying fox Pteropus dasymallus. The situation in this region has remained in need of clarification. We present here the results of some of our works done on P. dasymallus in the frame of the Island Bat Research Group (IBRG - www.batresearch.net), a Japanese unit that we created to coordinate and support works by students and researchers interested in bat conservation. Our research showed the crucial ecological role played by this fruit bat in Ryukyu island ecosystems while unveiling the significant threats that it faces through conflicts with humans. In the last part of this talk, we provide a glimpse on collaborative projects that may lead to a better understanding of the ecology of this elusive species, a diminution in human-wildlife conflicts, and a reduction in the risk to see its population collapse in the future.