DOI: 10.5061/dryad.pvmcvdnvj
title: Sex-speciﬁc expression of circadian rhythms enables allochronic speciation

description: Noctuid moths provide prime examples of species in various stages of
 allochronic speciation, where reproductive barriers are mediated by
 genetic divergence in daily or seasonal timing. Theory indicates that
 allochronic divergence might be one of the most plausible mechanisms of
 adaptive speciation, especially when timing is subject to divergent
 ecological selection. Here we show that the validity of this theoretical
 expectation is entirely contingent on species characteristics of the
 mating system. Our analysis focuses on the moth Spodoptera frugiperda
 (Lepidoptera, Noctuidae), which occurs as two strains that differ in
 circadian reproductive activity. Unlike in generic models of assortative
 mating, where chronotypes diverge under mild assumptions, individual-based
 evolutionary simulations of the mating system and life cycle of S.
 frugiperda fail to recover allochronic diversification, even under
 conditions highly conducive to speciation. Instead, we observe that both
 chronotypes advance their activity schedule towards the early night,
 resulting in a rapid loss of allochronic variation. This outcome is caused
 by the fact that mating in S. frugiperda takes considerable time and
 potential mates are encountered sequentially, so that early males enjoy a
 systematic advantage. The undermining effect of male mate competition can
 be overcome when circadian genes evolve sex-specific expression, enabling
 early and late chronotypes to be maintained, or even to diversify in
 sympatry. These results give new significance to sex differences in
 biological rhythms, and suggest that species characteristics of the mating
 system and genetic architecture are key to understanding the scope for
 allochronic speciation across diverse species exhibiting variation in
 timing.
description: This archive contains annotated C++ code for the individual-based
 evolutionary simulation model analysed in the paper. Code was compiled and
 run on MacOS, Windows and Linux operating systems, using, respectively,
 XCode 13.4.1., Visual Studio Code 1.92.2. and GCC 11.3.0. 
description: # Sex-speciﬁc expression of circadian rhythms enables allochronic
 speciation
 [https://doi.org/10.5061/dryad.pvmcvdnvj](https://doi.org/10.5061/dryad.pvmcvdnvj) ## Description of the data and file structure This archive contains annotated C++ code for the individual-based evolutionary simulation model analysed in: G. Sander van Doorn, Jens Schepers, Roelof A. Hut & Astrid T. Groot\ Sex-specific expression of circadian rhythms enables allochronic speciation\ (accepted for publication in Evolution Letters) ### Files and variables #### File: model.cpp **Description:** C++ source file, programme entry point and high-level model implementation #### Files: moth.h, random.h, utils.h **Description:** C++ header files, containing class definitions and prototypes for pseudorandom-number and utility routines #### Files: moth.cpp, random.cpp, utils.cpp **Description:** C++ sources files, containing class and function implementations ## Code/software Code was compiled and run on MacOS using XCode 13.4.1; on Windows using Visual Studio Code 1.92.2.; and on a Unix system (Habrok High-Performance Computing Cluster) using GCC 11.3.0.  ## Access information Other publicly accessible locations of the data: * N/A Data was derived from the following sources: * Software was written by the 1st author