DOI: 10.5061/dryad.sn02v6x0n
title: Queen-worker conflict can drive the evolution of social polymorphism and split sex ratios in facultatively eusocial life-cycles

description: Hamilton’s idea that haplodiploidy favors the evolution of altruism – the
 haplodiploidy hypothesis -- relies on the relatedness asymmetry between
 the sexes, caused by the sex-specific ploidies. Theoretical work on the
 consequences of relatedness asymmetries has significantly improved our
 understanding of sex-allocation and intra-colony conflicts, but the
 importance of haplodiploidy for the evolution of altruism came to be seen
 as minor. However, recently it was shown that haplodiploidy can strongly
 favor the evolution of eusociality, provided additional “preadaptations”
 are also present, such as the production of multiple broods per season and
 maternal ability to bias offspring sex ratios. These results were obtained
 assuming no influence of workers on the sex ratio, even though worker
 control of the sex ratio is known to occur. Here we model the evolution of
 sex-specific fratricide as a mechanism of worker control over the sex
 ratio. We show that fratricide can facilitate the initial evolution of
 helping. However, fratricide can also hamper the evolution of
 unconditional help. Instead, social polymorphism evolves, a mixture of
 helping and dispersing offspring. Finally, we show that the co-evolution
 of sex-allocation strategies of workers (fratricide) and queens leads to a
 split production of the sexes, with some colonies specializing in males
 and others in females. Thus, the model predicts that fratricide spawns a
 diversity of co-existing life cycles that strongly vary in degree of
 sociality and sex ratios.
description: All the data for the paper was generated by running individual
 based simulations written in c++ language. The code both for generating
 the data and for figure of the published article can be found in
 here: DOI:
 10.5281/zenodo.3361665 Files names starting
 with the identifier "evol" correspond to the evolutionary
 trajectories, while files named starting with "dist" correspond
 to phenotypic distributions at the end of the evolutionary process. After
 the identifier, file names contain 3 numbers, each one followed by the
 information of the simulation they communicate. The first number gives the
 seed used in the random number generator for that particular simulation,
 it is followed by the word "seed". The second number provides
 the value used in parameter phi multiplied by 10, for convenience, and it
 is followed by the word "phi". Finally, the last number gives
 the value used in parameter b multiplied by 10, and it is followed by the
 letter b.  The files of evolutionary trajectories
 contain data on the central tendency and spread of the 5 phenotypic trait
 along the evolutionary process. The 16 columns in the files correspond to:
 generation, mean for z1, mean for z3, mean for z5, mean for h, mean
 for omega, standard deviation for z1, standard deviation for z3, standard
 deviation for z5, standard deviation for h, standard deviation for omega,
 first quartile for z1, first quartile for z3, first quartile for z5, 
 first quartile for h,  first quartile for omega,  third quartile for
 z1,  third quartile for z3,  third quartile for z5,  third quartile for
 h,  third quartile for omega.  The files with the
 phenotypic distribution at the end of the evolutionary process contain
 values for the traits of different individuals in the population. The five
 columns correspond to: z1, z3, z5, h, omega.