葉に擬態する1億6500万年前の直翅目昆虫を発見(Scientists Discover 165-Ma Jurassic Orthopterans with Leaf Mimicry, First for Co-preserved Insect-Plant Fossils)

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2025-09-05 中国科学院(CAS)

中国科学院南京地質古生物研究所の黄迪英教授らは、約1億6500万年前のジュラ紀中期に生息したバッタ目昆虫3新種を内モンゴルで発見しました。前翅の模様が絶滅植物アノモザミテス属の葉に酷似しており、同一堆積層で昆虫と植物が共に保存された初の化石例です。ある種は横帯と縦筋で葉脈を再現し、別の種は左右の翅を合わせると葉の形を示すなど、高度な擬態を示しました。統計解析では、中ジュラ紀に模倣昆虫と植物多様性が共に頂点を迎え、その後減少する傾向が確認され、昆虫と植物の共進化を示唆します。さらに植物化石には摂食痕が残されており、捕食圧が擬態進化を促した可能性が高いとされます。本成果は、古代生態系における防御戦略と種間相互作用を理解する重要な証拠です。

葉に擬態する1億6500万年前の直翅目昆虫を発見(Scientists Discover 165-Ma Jurassic Orthopterans with Leaf Mimicry, First for Co-preserved Insect-Plant Fossils)Fossil leaves of Anomozamites. (Image by NIGPAS)

<関連情報>

ジュラ紀昆虫に見られる特異な葉の擬態
Unique leaf mimicry in Jurassic insects

Yanzhe Fu;Chong Dong;Dolev Fabrikant;Chenyang Cai;Carolin Haug;Joachim T. Haug;Diying Huang
Geology  Published:August 28, 2025
DOI:https://doi.org/10.1130/G53399.1

Animals have evolved diverse defensive strategies under selective pressures, with mimicry being a crucial survival strategy for insects. Leaf mimicry is widespread in modern ecosystems, yet its fossil record remains sparse, often lacking direct evidence of target plant or clear morphological adaptations. We report three novel cases of leaf mimicry in Jurassic orthopterans (grasshoppers and crickets, including katydids) (Prophalangopsidae) from the Daohugou biota (ca. 163.5 Ma, northeastern China), in which the forewings exhibit highly specialized contrasting color patterns that closely resemble the abundantly co-occurring bennettitalean (extinct seed-bearing, cycad-like group) leaves. These cases provide the first unambiguous evidence in which both the mimicking insects and their plant models are preserved in the same bedding plane. It represents the first known instance of orthopteran mimicry in the Jurassic, fills a gap in the fossil record, and suggests that leaf mimicry has been a long-standing adaptive strategy in Orthoptera, independently evolving across different lineages throughout geological history. This finding highlights the dynamic interplay between plant community succession, predation pressures, and insect defensive strategies, expanding our understanding of the ecological significance and evolution of leaf mimicry in orthopterans.

生物環境工学
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