Honors Theses
Date of Award
2018
Document Type
Undergraduate Thesis
Department
Biology
First Advisor
Lainy Day
Relational Format
Dissertation/Thesis
Abstract
Manakins are a suboscine, lekking bird of the tropical and subtropical regions of South and Central America that perform complex mating displays shaped by sexual selection. The complexity of the mating display varies greatly across species of manakins. Some manakins only perform a limited number of different motor elements, whereas others have elaborate displays that consist of acrobatic movements and mechanical sound production. The complexity of these displays has been found to be positively related to brain weight, brain volume, arcopallium volume, body weight, and tarsus size but shows no relationship to the nucleus rotundus or nucleus taeniae. The volume of the cerebellum is also positively related to display complexity. The cerebellum is a neural structure that functions in coordinating motor control and motor learning. The cerebellum is made up of the cerebellar cortex and the deep cerebellar nuclei. The cerebellar cortex is divided into major layers: the molecular layer, granular cell layer, and Purkinje cell layer. Cells within these layers are homogeneously distributed across the cerebellum and perform distinct functions in cerebellar signal processing. We hypothesized that the output cells of the cerebellum, the Purkinje cells, may play a prominent role in driving the positive relationship between overall cerebellar volume and display complexity. We quantified Purkinje cell number and cell volume in 6 manakin species, and Purkinje cell layer volume in 12 species of manakins and used the closely related ochre-bellied flycatcher as an outgroup. We found a positive relationship between Purkinje cell number and display complexity within manakins upon exclusion of the flycatcher outgroup. Neither Purkinje cell layer volume nor cell volume was related to display complexity. Purkinje layer data was analyzed alone and in the context of a larger data set showing other brain region and body size measurements that are positively associated with display complexity in these individuals. Results are discussed in this context as well as in relationship to Purkinje cell and cerebellar function.
Recommended Citation
Harvey, Mary, "Purkinje Cell Morphology and Display Complexity in Manakins (Pipridae)" (2018). Honors Theses. 649.
https://egrove.olemiss.edu/hon_thesis/649
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