Behaviour 2019
Correlated Evolution of Acrobatic Display and both Neural and Somatic Phenotypic Traits in Manakins (Pipridae)
Lainy B. Day1,2, Wilson Helmhout2, Glendin Pano2, Jason D. Hoeksema1, Willow R. Lindsay2,3. 1Department of Biology, University of Mississippi, University, MS, United States; 2Neuroscience Minor, University of Mississippi, University, MS, United States; 3Department of Biological and Environmental Sciences, Gothenburg, , Sweden

To attract females, manakin (Aves: Pipridae) males perform acrobatic displays punctuated by non-vocal sounds. Display complexity varies across species and neuromuscular, skeletal, and endocrine systems coevolve with display elements in the few species studied. In a broad comparative study, we found display complexity and both brain mass and body mass coevolved, which could be due to overall brain and body expansion or mosaic increases in only functionally relevant brain and body features. We predicted positive associations between complexity and the volume of sensorimotor and procedural processing brain regions and no association of complexity with two control regions. We expected body mass but not tarsus length would predict complexity as selection on tarsus length is relatively constrained in manakins. Our study of 12 manakin species and supports mosaic evolution of neural and body features relevant to display and indicate sexual selection for acrobatics increases procedural learning via cerebellar enlargement and maneuverability via a reduction in tarsus length and suggests future studies finely parse display elements to clearly understand brain, body, and biomechanic evolution.