2025-02-04 ペンシルベニア州立大学(PennState)
ペンシルベニア州立大学の研究チームは、南米の約5,200万年前の化石葉に見られる昆虫の食害痕が、現代のオーストラリアのユーカリ属(Eucalyptus)の葉と類似していることを発見しました。アルゼンチンのラグーナ・デル・フンコで発見された化石葉284枚を分析し、現代のユーカリ葉1万枚以上と比較した結果、外部摂食や虫こぶ、葉内トンネルなどの食害パターンが確認されました。この研究は、植物と昆虫の進化的関係が数千万年にわたり安定している可能性を示し、陸上生態系の進化を理解する上で重要な知見を提供します。
<関連情報>
- https://www.psu.edu/news/earth-and-mineral-sciences/story/fossils-show-leaf-eating-insects-tracked-gum-trees-millions-years
- https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.20316
オーストラリアのユーカリの進化の歴史と生物多様性を示す昆虫食の化石が発見される Fossil insect-feeding traces indicate unrecognized evolutionary history and biodiversity on Australia’s iconic Eucalyptus
L. Alejandro Giraldo, Peter Wilf, Michael P. Donovan, Robert M. Kooyman, Maria A. Gandolfo
New Phytologist Published: 28 November 2024
DOI:https://doi.org/10.1111/nph.20316
Summary
- Fossilized plant–insect herbivore associations provide fundamental information about the assembly of terrestrial communities through geologic time. However, fossil evidence of associations originating in deep time and persisting to the modern day is scarce.
- We studied the insect herbivore damage found on 284 Eucalyptus frenguelliana leaves from the early Eocene Laguna del Hunco rainforest locality in Argentinean Patagonia and compared damage patterns with those observed on extant, rainforest-associated Eucalyptus species from Australasia (> 10 000 herbarium sheets reviewed).
- In the fossil material, we identified 28 insect herbivory damage types, including 12 types of external feeding, one of piercing-and-sucking, five of galls, and 10 of mines. All 28 damage types were observed in the herbarium specimens.
- The finding of all the fossil damage types on extant Eucalyptus specimens suggests long-standing associations between multiple insect herbivore lineages and their host genus spanning 52 million years across the Southern Hemisphere. This long-term persistence, probably enabled through niche conservatism in wet eucalypt forests, demonstrates the imprint of fossil history on the composition of extant insect herbivore assemblages. Although the identities of most insect culprits remain unknown, we provide a list of Eucalyptus species and specific population locations to facilitate their discovery, highlighting the relevance of fossils in discovering extant biodiversity.
