Occurrence of the Invasive Western Conifer Seed Bug Leptoglossus occidentalis (Hemiptera: Coreidae) in Iriomote Island, the Yaeyama Islands, Japan and Inference of Its Sources Based on the Literature and Citizen Science Records

Abstract

Leptoglossus occidentalis (Hemiptera: Coreidae) was recorded from Iriomote Island, Okinawa, Japan, as the first record of this species from the Yaeyama Islands and the island itself. A review of the extant literature and citizen science records suggests that Taiwan may be a possible source of the species on Iriomote Island, as either an early invasion stage or an accidental arrival. However the possibility of three distinct introduction routes, from mainland Japan (Honshu or Kyushu), Okinawa Island, or Taiwan, of human-mediated or natural dispersal could not be ruled out. On Okinawa Island, the species might be rapidly expanding from the northern area of the island. Since the initial invasion 16 years ago, the species has spread to nearly all regions in Japan, indicating that it might have passed the early stages of invasion, although its multiple origins remain possible.