Notoplatylabus podolicus conterraneus Tereshkin, 1993

Notoplatylabus podolicus conterraneus Tereshkin, 1993 View in CoL

Material. [ Japan] Kagoshima Pref.: Yakushima Isl. , Malaise trap ( AC3 ), 150 m alt., 1 ♀ 8–28. VI. 2007, Malaise trap (H2), 250 m alt., 1 ♀ 5–8. VI. 2007, leg. T. Yamauchi et al . ( Kanagawa).

Description. Female. Body length 7.5 mm. Flagellum with 35 flagellomeres, bristle-shaped, 1 st flagellomere 5.0× as long as wide. OED 0.9× ocellar diameter. MI 0.9. Hind femur 3.5× as long as wide. Thyridium transverse, 0.6× as wide as interval between thyridia. 2 nd tergite as wide as long. Structure and coloration otherwise as described by Tereshkin (1993).

Distribution. Japan (Yakushima Isl.), Far East Russia and Korea. New record for Japan.

Species diversity and distribution pattern of Ichneumoninae in the Ryukyu Archipelago

The results of this study have increased the number of species of Ichneumoninae in the Ryukyu Archipelago from only 27 previously recorded to 45, an increase of about 1.7 times ( Table 2). However, this number is less than 20% of the total number of species in Japan, indicating that the number of species in this area is relatively low. This may be due to the effect of the relatively small area size of the islands in this archipelago.

Table 3 arranges the islands in the order of the number of Ichneumonine species in Table 2 and notes the area and highest altitude of each island. Although the area and maximum altitude of the islands appear to be related to the number of species, there are some survey biases, such as ease of access and the presence or absence of comprehensive sampling (e. g. Malaise trap), which require further investigation in the future. It should be noted that the number of Ichneumonine species on Yakushima is prominent compared to other islands and has a higher number of species than Amamioshima and Okinawajima, where survey accuracy is similarly high. This is probably due to its proximity to Kyushu and its elevation above 1900 m, which is much higher than the other islands in the Ryukyu Archipelago.

Discussion of the endemism of individual species is difficult with the current accuracy of survey. Although a number of new species have been described from Yakushima in this study, Ichneumoninae are also poorly studied in Japan as a whole, and some of these species may be found in other parts of Japan, such as Kyushu (especially in the southern area). However, species such as Vulgichneumon takagii ( Uchida, 1956) from Amamioshima and Vulgichneumon okinawae sp. nov. from Okinawajima may be endemic to the island or semi-endemic to the island group to which they belong.

It is noteworthy that the Ichneumoninae of the Ryukyu Archipelago do not include Stenichneumon Thomson, 1893 , which has several species and relatively abundant populations in mainland of Japan ( Hokkaido, Honshu, Shikoku and Kyushu) and Taiwan, located at both ends of the Ryukyu Archipelago. This may be due to the limiting factor of their biology such as host prefercences.