Neural Evolution of Context-Dependent Fly Song

Yun Ding,Joshua L. Lillvis,Jessica Cande,Gordon J. Berman,Benjamin J. Arthur,Xi Long,Min Xu,Barry J. Dickson,David L. Stern

doi:10.1016/j.cub.2019.02.019

Abstract

It is unclear where in the nervous system evolutionary changes tend to occur. To localize the source of neural evolution that has generated divergent behaviors, we developed a new approach to label and functionally manipulate homologous neurons across Drosophila species. We examined homologous descending neurons that drive courtship song in two species that sing divergent song types and localized relevant evolutionary changes in circuit function downstream of the intrinsic physiology of these descending neurons. This evolutionary change causes different species to produce divergent motor patterns in similar social contexts. Artificial stimulation of these descending neurons drives multiple song types, suggesting that multifunctional properties of song circuits may facilitate rapid evolution of song types.

Highlights

Animals display an extraordinary diversity of behaviors
We found that D. yakuba males preferentially sang clack song at relatively higher velocity and across a wide range of distances and positions relative to females (Figures 1E–1G)
We compared the function of the descending neurons that transmit information about social context to neurons that pattern songs to identify where in the nervous system evolutionary changes have caused this change in context-dependent song production

Summary

Introduction

The evolution of behavior in response to natural selection has been studied for many years, the neural differences that underlie behavioral diversity are poorly understood. Given the hierarchical and modular structure of neural networks underlying specific behaviors, it seems possible that some nodes in the nervous system are more evolvable than others [1]. Are evolutionary changes distributed randomly across all neural circuit nodes required to perform a behavior? Several studies have begun to elucidate how changes in homologous neurons have contributed to behavioral evolution [3,4,5,6,7,8,9,10,11,12]. A satisfying answer to the broad evolutionary questions posed above requires a systematic methodology to identify and functionally manipulate homologous neurons

Methods

Results

Discussion

Conclusion