Developmental bias in the evolution and plasticity of beetle horn shape

• Published in: Proceedings of the Royal Society. B, Biological sciences Vol. 289; no. 1983; p. 20221441
• Main Authors: Rohner, Patrick T., Hu, Yonggang, Moczek, Armin P.
• Format: Journal Article
• Language: English
• Published: England The Royal Society 28.09.2022
• Subjects: Animals; Bias; Biological Evolution; Coleoptera - genetics; Evolution; Phenotype; integration; developmental bias; fluctuating asymmetry; geometric morphometrics; developmental plasticity; Onthophagus
• ISSN: 0962-8452; 1471-2954; 1471-2954
• DOI: 10.1098/rspb.2022.1441

The degree to which developmental systems bias the phenotypic effects of environmental and genetic variation, and how these biases affect evolution, is subject to much debate. Here, we assess whether developmental variability in beetle horn shape aligns with the phenotypic effects of plasticity and evolutionary divergence, yielding three salient results. First, we find that most pathways previously shown to regulate horn length also affect shape. Second, we find that the phenotypic effects of manipulating divergent developmental pathways are correlated with each other as well as multivariate fluctuating asymmetry—a measure of developmental variability. Third, these effects further aligned with thermal plasticity, population differences and macroevolutionary divergence between sister taxa and more distantly related species. Collectively, our results support the hypothesis that changes in horn shape—whether brought about by environmentally plastic responses, functional manipulations or evolutionary divergences—converge along ‘developmental lines of least resistance’, i.e. are biased by the developmental system underpinning horn shape.