Group mating in Cretaceous water striders

Proceedings of the Royal Society B Biological Sciences, vol. 291, pp. 20232546

Abstract

Fossilized mating insects are irreplaceable material for comprehending the evolution of the mating behaviours and life-history traits in the deep-time record of insects as well as the potential sexual conflict. However, cases of mating pairs are particularly rare in fossil insects, especially aquatic or semi-aquatic species. Here, we report the first fossil record of a group of water striders in copulation (including three pairs and a single adult male) based on fossils from the mid-Cretaceous of northern Myanmar. The new taxon, Burmogerris gen. nov., likely represents one of the oldest cases of insects related to the marine environment, such as billabongs formed by the tides. It exhibits conspicuous dimorphism associated with sexual conflict: the male is equipped with a specialized protibial comb as a grasping apparatus, likely representing an adaptation to overcome female resistance during struggles. The paired Burmogerris show smaller males riding on the backs of the females, seemingly recording a scene of copulatory struggles between the sexes. Our discovery reveals a mating system dominated by males and sheds light on the potential sexual conflicts of Burmogerris in the Cretaceous. It indicates the mating behaviour remained stable over long-term geological time in these water-walking insects.

Authors 6

1. Yanzhe Fu

   Chinese Academy of Sciences · Nanjing Institute of Geology and Paleontology · State Key Laboratory of Palaeobiology and Stratigraphy · Ludwig-Maximilians-Universität München

   Affiliation as printed

   Department of Biology II, Ludwig-Maximilians-Universität München, Biocenter, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany

   State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, and Centre for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China

2. Chenyang Cai

   Chinese Academy of Sciences · Nanjing Institute of Geology and Paleontology · State Key Laboratory of Palaeobiology and Stratigraphy

   Affiliation as printed

   State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, and Centre for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China

3. Pingping Chen Aachen Section Entomology Naturalis Biodiversity Center

   Naturalis Biodiversity Center

   Affiliation as printed

   Section Entomology, Naturalis Biodiversity Centre, 2300 RA Leiden, The Netherlands

4. Qiang Xuan

   Chinese Academy of Sciences · Nanjing Institute of Geology and Paleontology · State Key Laboratory of Palaeobiology and Stratigraphy

   Affiliation as printed

   State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, and Centre for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China

5. Tin Aung Myint

   Mandalay University

   Affiliation as printed

   Department of Geology, University of Mandalay, Mandalay, Myanmar

6. Diying Huang corresponding

   Chinese Academy of Sciences · Nanjing Institute of Geology and Paleontology · State Key Laboratory of Palaeobiology and Stratigraphy

   Affiliation as printed

   State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, and Centre for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China