Mandible evolution in the Scarabaeinae (Coleoptera: Scarabaeidae) and adaptations to coprophagous habits
- PDF / 3,998,933 Bytes
- 10 Pages / 595.276 x 793.701 pts Page_size
- 85 Downloads / 174 Views
RESEARCH
Open Access
Mandible evolution in the Scarabaeinae (Coleoptera: Scarabaeidae) and adaptations to coprophagous habits Ming Bai1*†, Sha Li1,2†, Yuanyuan Lu1,2, Haidong Yang1, Yijie Tong1 and Xingke Yang1*
Abstract Introduction: The astonishing spectrum of scarabaeine lifestyles makes them an attractive group for studies in entomology and evolutionary biology. As a result of adaptions to specific food substrates and textures, the mouthparts of dung beetles, particularly the mandible, have undergone considerable evolutionary changes and differ distinctly from the presumptive ancestral conditions of the Coleoptera and Polyphaga. The possible functions of dung beetle mouthparts and the evolution of dung feeding have been controversial for decades. Results: In this study, 187 scarabs representing all tribes of the Scarabaeinae and the major lineages within the Scarabaeoidea, along with three major feeding types within the Scarabaeoidea (omnivory, phytophagy and coprophagy), were studied. Based on geometric morphometric and three-dimensional (3D) reconstruction approaches, morphological differences in mandibles among the three feeding types were identified. The ancestral forms of the mandible within the Scarabaeinae were reconstructed and compared with those of modern species. The most recent common ancestor of the Scarabaeinae fed on soft materials, and the ancestor of the Scarabaeinae and the Aphodiinae was in an evolutionary transition between processing more solid and softer substrates. Conclusions: Coprophagy originated from omnivorous ancestors that were very likely saprophagous. Furthermore, phytophagy may also have originated from omnivory. In addition, our study addresses the integration and modularity of geometric morphometric data in a phylogenetic context. Keywords: Coprophagy, Dung beetle, Mouthparts, 3D, Geometric morphometric
Introduction Decomposers use deceased organisms and non-living organic compounds as their food source. By breaking down dead material, they provide nutrients that are crucial to the environment and essential for the survival of other organisms. Many species of bacteria, fungi and protists, the primary decomposers, are unable to ingest discrete masses of matter, but instead absorb and metabolize resources on a molecular scale. Insect decomposers, such as dung beetles, burying beetles, fly maggots, and others generally consume larger quantities of organic matter [1]. Vertebrate dung is a special niche * Correspondence: [email protected]; [email protected] † Equal contributors 1 Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Box 92Beichen West RoadChaoyang District, Beijing 100101, People’s Republic Of China Full list of author information is available at the end of the article
that is considered highly desirable and nutritious to potential dung colonizers. A typical dung community consists of dung feeders or predators, many of which are beetles. These groups include species of the scarabaeoid Scarabaeinae, Aphodiinae, G
Data Loading...
