皇居の蛾類モニタリング調査(2000-2005) (皇居の動物相モニタリング調査) [in Japanese] Monitoring survey (2000-2005) of moths (Insecta, Lepidoptera) in the garden of the imperial palace, Tokyo, Central Japan [in Japanese]
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Six hundred and thirty-three moths in 46 families were collected in the Imperial Palace, Tokyo, ca. 115 ha. The survey was carried out from June 2000 to December 2005 by using a light, sugar bait and by ordinary day-time survey of adults and larvae. All the collecting data are given in the list, in which some noteworthy moths are commented in comparison with the records of such green tracts in the urban Tokyo as the Imperial Palace, Tokyo, 1996-2000 (Owada et al., 2000), the garden of the Institute for Nature Study, ca. 20 ha, 1998-2000 (Owada et al., 2001), the Akasaka Imperial Gardens, ca. 51 ha, 2002-2004 (Owada et al., 2005a) and the Tokiwamatsu Imperial Villa, ca. 2 ha, 2002-2004 (Owada et al., 2005b). The comparison of each result is shown in Tables 1 and 2. During a decade of survey period from 1996 to 2005, we observed the establishment and outbreak of a tortricid moth Cerace xanthocosma in the Imperial Palace, Tokyo, and the Akasaka Imperial Gardens (Owada et al., 2000, 2001, 2005a), and the details were summarized in the report of moths of the Tokiwamatsu Imperial Villa, Tokyo (Owada et al., 2005b). We became aware of the remarkable outbreak in the early spring of 2003, i. e., many nests made by the larvae of this tortricid moth were found on leaves of evergreen trees everywhere in the Imperial Palace and the Akasaka Imperial Gardens, Tokyo. This moth is bivoltine in Tokyo urban forests, adults fly in June-July and September. The outbreak of adult moths was observed in 2003 and 2004, but ended rapidly in the winter of 2004, when hibernating larval nests were mostly disappeared in the Imperial Palace. In 2005, the density level of adult moths backed to that in 2001-2001, a few or no moths were observed in each investigation of its flight periods. We had found and bread larvae of this polyphagous moth on the following 17 evergreen broadleaved trees in 11 families. Araliaceae: Fatsia japonica; Aquifoliaceae: Ilex pedunculosa; Caprifoliaceae: Viburnum odoratissimum var. awabuki; Eericaceae: Pieris japonica; Euphorbiaceae: Daphniphyllum himalaense; Fagaceae: Castanopsis sieboldii, Lithocarpus edulis; Lardizabalaceae: Extauntonia hexaphylla; Lauraceae: Cinnamomum camphora, Cinnamomum japonicum, Machilus thunbergii; Myricaceae: Myrica rubra; Oleaceae: Lingustrum japonicum; Theaceae: Camellia japonica, Camellia sasanqua, Camellia sinensis, Cleyera japonica. Most of lithosiine moths, Arctiidae, are lichen and algae feeders, and usually very common in any forests and grasslands. In the 1970-1980's, air pollution was very serious in Japan, and lithosiine moths, except for marshy moths of Pelosia spp., might have become once extinct in the Tokyo urban areas. From the 1990's onwards, air pollution was eased to some extent, and the flora of lichens and bryophytes began to restore in forests of city areas of Tokyo (Kashiwadani & Thor, 2000; Kashiwadani et al., 2001; Higuchi, 2001). In fact, some lithosiine moths were collected in the Institute for Nature Study, the Akasaka Imperial Gardens and the Tokiwamatsu Imperial Villa in 1998-2004, and they may already settle down in these forests. At the Imperial Palace, Tokyo, we were able to collect a female of Miltochrista abberans on 3 June, 2004, but we have collected none in 2005. It is quite likely that lithosiine moths will not settle down in the Imperial Palace grounds, which are the largest and richest the fauna and flora among large green tracts in urban Tokyo. This phenomenon may be one of the evidences of extinction of lithosiine moths in the urban Tokyo. There is a possible barrier, which obstructs the invasion of lithosiine moths to the Imperial Palace, that is, large moats completely surround the Palace. In larger moats, the longest width of water is ca. 100m, and is ca. 50m in smaller ones.
- Memoirs of the National Science Museum, Tokyo
Memoirs of the National Science Museum, Tokyo (43), 37-136, 2006-03
National Science Museum