Early specializations for mimicry and defense in a Jurassic stick insect

Hongru Yang; Chaofan Shi; Michael S Engel; Zhipeng Zhao; Dong Ren; Taiping Gao

doi:10.1093/nsr/nwaa056

Early specializations for mimicry and defense in a Jurassic stick insect

Natl Sci Rev. 2020 Apr 2;8(1):nwaa056. doi: 10.1093/nsr/nwaa056. eCollection 2021 Jan.

Authors

Hongru Yang¹, Chaofan Shi², Michael S Engel³, Zhipeng Zhao¹, Dong Ren¹, Taiping Gao¹

Affiliations

¹ College of Life Sciences and Academy for Multidisciplinary Studies, Capital Normal University, Beijing 100048, China.
² School of Earth Sciences and Engineering, Guangdong Provincial Key Lab of Geodynamics and Geohazards, Guangdong Provincial Key Laboratory of Mineral Resources & Geological Processes, Sun Yat-sen University, Guangzhou 510275, China.
³ Division of Entomology, Natural History Museum, and Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA.

Abstract

Mimicry and secondary defense are staples among predator-prey interactions. Among insects, the stick and leaf insects are masters of camouflage. Nonetheless, a meager understanding of their origin and early mimetic evolution persists. Here, we report the earliest mimetic and defensive strategies of a stick insect from the Middle Jurassic of China, Aclistophasma echinulatum gen. et sp. nov., exquisitely preserving abdominal extensions and femoral spines. The distribution of these characteristics mapped onto the phylogeny of Phasmatodea reveals that abdominal extensions and femoral spines developed multiple times during the evolution of stick insects, and indicates that the origin of abdominal extensions predates other modifications, while tergal extensions predate other expansions of the body, such as those of the sterna and pleura, as well as defensive femoral spines. The new fossil provides clues into early antipredator defensive strategies, allows inferences as to the potential environment and predators, and reveals the mimetic and defensive mechanisms of stick insects from 165 million years ago.

Keywords: Susumanioidea; abdominal extension; antipredator strategy; evolution; phylogeny.