yrammuS 要概内海 俊介83Shunsuke UTSUMIシロツメクサ都市適応進化と都市－生態－進化連関：ニッチモデリングによるアプローチ(2021採択)Urban evolution in white clover and city-eco-evolutionary interplays: a niche modeling approach(Project 2021)65Rep. Grant. Res., Asahi Glass Foundation (2022)Molecular and morphological analyses were used to resolve the taxonomy of the copepod Metridia pacifica species complex in the North Pacific. Phylogenetic analysis of mitochondrial cytochrome c oxidase subunit I (COI) revealed two lineages of M. lucens and M. pacifica, and M. pseudopacifica in the eastern Pacific was in-cluded in M. lucens. The presence of M. lucens and M. pacifica was confirmed across the North Pacific, and genetic structures were observed in M. lucens between eastern and western North Pacific. The morphological identification character of length of setae on the fifth pair of legs was not useful for classifying adult female M. pacifica and M. lucens. However, combinations of prosome length and head angle successfully classified >98.2% of M. pacifica and M. lucens specimens from the North Pacific. Because M. lucens and M. pacifica have different distribution patterns and ecologies, accurate classification of these two species leads to improving detection of ecosystem change in the oceans.近年，都市化に伴う劇的な環境変化が生命の進化に影響を与えることが報告されている．しかし，都市から郊外への様々な環境勾配の非線形性や形質の多機能性から，都市環境が進化の軌跡や結果にどのような影響を与えるかについては，まだ解明されていないことが多い．本研究では，遺伝的に決定される被食防御形質であるシロツメクサ（Trifolium repens L.）のシアン化水素（HCN）生産／非生産とその構成要素（シアノ配糖体および加水分解酵素の生産／非生産）に着目し，都市環境における植物の進化と適応について調査した．122集団から合計3466株のシロツメクサを採取し，都市部から郊外部にかけてのHCN生成型の頻度や，シアン配糖体および加水分解酵素の有無の頻度についての空間パターンを検討した．都市部から郊外部にかけて，気温・NDVI・開空度などの各環境要因は複雑な空間変動を示した．特に，都市構造に関連する被食圧と不浸透面率は，集団におけるHCN生成の頻度の違いを生み出すことが明らかになった．また，不浸透面率はシアン配糖体の集団内頻度に影響を与えるが，草食圧は影響を与えないことも明らかにした．都市化による不浸透面率の上昇が環境の湿潤化を促進し，乾燥耐性機能を持つシアン配糖体を生成しない進化を促進することを示唆する．さらに，都市景観における開空度と残存森林のモザイク構造が被食圧の不均一な分布を決定づけ，そのことが都市-郊外一帯におけるHCN生成型になるか非生成型になるかという進化を促すことが明らかになった．そして，ニッチモデリングによって，HCN生成頻度や構成要素の遺伝子の頻度に関する空間パターンを推定した．Recently, dramatic environmental changes associated with urbanization have been reported to impact evolution of lives. However, much remains to be elucidated about how urban environments influence evolutionary trajectories and outcomes due to non-linearity of various environmental gradients from urban to rural and the traits multifunctionality. Here, we focused on hydrogen cyanide (HCN) production of white clovers (Trifolium repens L.), which are genetic herbivory defense traits, and its compo-nents (production/non-production of cyanogenic glycosides and hydrolytic enzymes) to survey how plants evolve and adapt in urban environment. We collected total of 3466 white clover plants from 122 population to examine the spatial variation of cyanogenesis and the presence/absence of cyanogenic glycosides and hy-drolytic enzymes from urban to rural. From urban to rural, each environmental factor showed complex spatial variation. In particular, herbivory pressure and impervious surface rate, which are related to urban structure, resulted in different frequencies of cyanogenesis in populations. We also found that impervious surface rate affected the within-population frequency of cyanogenic glycoside production, while herbivory pressure did not. These results suggest that increasing impervious surface rate due to urbanization promotes wetness, which in turn promotes the evolution of non-cyanogenic glycoside production with drought tolerance func-tions to reduce production costs. Furthermore, the mosaic structure of sky openness and remnant forest in ur-ban landscapes determines the heterogeneous distribution of herbivory pressure, which in turn drives the
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