Sex differences in ageing and lifespan are ubiquitous in nature. The "unguarded-X” hypothesis (UXh) suggests they may be partly due to the expression of recessive mutations in the hemizygous sex chromosomes of the heterogametic sex, which could help explain sex-specific ageing in a broad array of taxa. A prediction central to the UX hypothesis is that inbreeding will decrease the lifespan of the homogametic sex more than the heterogametic sex, because only in the former does inbreeding increase the expression of recessive deleterious mutations. In this study, we test this prediction by examining the effects of inbreeding on the lifespan and fitness of male and female Drosophila melanogaster across different social environments. We found that, across social environments, inbreeding resulted in a greater reduction of female than male lifespan, and that inbreeding effects on fitness did not seem to counterbalance sex-specific effects on lifespan, suggesting the former are maladaptative. Inter- and intra-sexual correlation analyses also allowed us to identify evidence of an underlying joint genetic architecture for inbreeding effects on lifespan. We discuss these results in light of the UXh and other alternative explanations, and suggest that more attention should be paid to the possibility that the “unguarded-X” may play an important role in the evolution of sex-specific lifespan.
Lifespan Data
Lifespan data for the manuscript accepted in Evolution titled as: "The “unguarded-X” and the genetic architecture of lifespan: Inbreeding results in a potentially maladaptive sex-specific reduction of female lifespan in Drosophila melanogaster". It also contains data from a previous experiment with the same design (Carazo P, Green J, Sepil I, Pizzari T, Wigby S (2016) Inbreeding removes sex differences in lifespan in a population of Drosophila melanogaster. Biology Letters 12(6): 20160337.). In the csv file the variables are as follows: ID (identification name for each isoline), LS (lifespan in days), IBR (inbreeding treatment), SE (social environment), SEX and finally EXP (name of the experiment, A is the one done by Carazo et al 2016 and B is the current experiment).
data_lifespan_combined.csv
Fitness Data
Fitness data for the manuscript accepted in Evolution titled as: "The “unguarded-X” and the genetic architecture of lifespan: Inbreeding results in a potentially maladaptive sex-specific reduction of female lifespan in Drosophila melanogaster". In the csv file the variables are as follows: ID (identification name for each isoline), IBR (inbreeding treatment), SRS (standardized reproductive success) and Sex.
data_fitness.csv
Lifespan Data (inbred and outbred)
Inbred/Outbred lifespan data for the manuscript accepted in Evolution titled as: "The “unguarded-X” and the genetic architecture of lifespan: Inbreeding results in a potentially maladaptive sex-specific reduction of female lifespan in Drosophila melanogaster". It also contains data from a previous experiment with the same design (Carazo P, Green J, Sepil I, Pizzari T, Wigby S (2016) Inbreeding removes sex differences in lifespan in a population of Drosophila melanogaster. Biology Letters 12(6): 20160337.). In the csv file the variables are as follows: Experiment (as the name of the experiment, A is the one done by Carazo et al 2016 and B is the current experiment), ID (identification name for each isoline), Sex, LSib (inbred lifespan in days), LSob (outbred lifespan in days), SE (Social Environment)
LF_inoutbred.csv
Lifespan Data (Male and Female)
Male/Female lifespan data for the manuscript accepted in Evolution titled as: "The “unguarded-X” and the genetic architecture of lifespan: Inbreeding results in a potentially maladaptive sex-specific reduction of female lifespan in Drosophila melanogaster". It also contains data from a previous experiment with the same design (Carazo P, Green J, Sepil I, Pizzari T, Wigby S (2016) Inbreeding removes sex differences in lifespan in a population of Drosophila melanogaster. Biology Letters 12(6): 20160337.). In the csv file the variables are as follows: Experiment (as the name of the experiment, A is the one done by Carazo et al 2016 and B is the current experiment), ID (identification name for each isoline), Inbreeding (the inbreeding treatment, LSm (male lifespan in days), LSf (female lifespan in days), SE (Social Environment).
LF_malefemale.csv
ID in lifespan data
Inbreeding depression in lifespan data for the manuscript accepted in Evolution titled as: "The “unguarded-X” and the genetic architecture of lifespan: Inbreeding results in a potentially maladaptive sex-specific reduction of female lifespan in Drosophila melanogaster". It also contains data from a previous experiment with the same design (Carazo P, Green J, Sepil I, Pizzari T, Wigby S (2016) Inbreeding removes sex differences in lifespan in a population of Drosophila melanogaster. Biology Letters 12(6): 20160337.). In the csv file the variables are as follows: Experiment (as the name of the experiment, A is the one done by Carazo et al 2016 and B is the current experiment), ID (identification name for each isoline), SE (Social Environment), dLSf (decrease due to inbreeding for females), dLSm (decrease due to inbreeding for females).
DeltaLF.csv
