DOI: 10.5061/dryad.5mkkwh7g6
title: Organizational effects of testosterone on the number of mating partners and reproductive success in females of a social rodent

description: The timing of exposure to testosterone produces activational and
 organizational effects in vertebrates. In females, high serum testosterone
 levels, and the exposure to high testosterone levels during early
 development, are negatively associated with female fertility and
 attractiveness to males. We tested these hypotheses by examining
 associations between serum testosterone levels (an indirect index of
 activational effects), anogenital distance (AGD, a direct index of
 organizational effects), and the number of male mating partners attained
 by females, and the number of offspring weaned. We examined 525 wild degu
 (Octodon degus) females across an 11-year study. During the mating season,
 we found no association between female serum testosterone levels and AGD,
 the number of male mating partners, or with the number of offspring
 weaned. However, we found that the number of male mating partners was
 positively associated with the number of offspring weaned, suggesting that
 females obtain direct fitness benefits from polyandrous mating. During the
 nursing season, we recorded a positive association between female AGD and
 the number of offspring weaned. This indicates that testosterone
 organizational effects had a positive effect on female fertility. This
 finding is unique within the theoretical framework of female phenotypical
 masculinization via intrauterine position phenomenon.
description: # Activational and organizational effects of testosterone on the number of
 mating partners and reproductive success in females of a social rodent
 [https://doi.org/10.5061/dryad.5mkkwh7g6](https://doi.org/10.5061/dryad.5mkkwh7g6) ## Description of the data and file structure README: Data for: Activational and organizational effects of testosterone on the number of mating partners and reproductive success in females of a social rodent Summary of dataset contents, contextualized in experimental procedures and results. Data contained in this file corresponds to individual and social group data from a wild population of degus (*Octodon degus*). This file only includes data for adult females. Data corresponds to data from the mating season (austral winter), and nursing season (austral spring), during eleven years (2009-2019). Mating season data (sheet 1) includes 10 years (2010-2019), nursing season data (sheet 2) includes 11 years (2009-2019). **File and variables** To test the prediction (i) about the potential effects of female serum testosterone levels, female anogenital distance (AGD), and the number of males within the social group, and their interactions, on the total number of male mating partners, run model model 1. This model run with n = 217 replicates, representing all females sampled (i.e., this examination included females with zero effective mates). The response variable is total number of male mating partners. Utilize data from sheet 1, “winter females”. To test prediction (ii) about the potential effects of female serum testosterone levels, female anogenital distance (AGD), and the number of males within the social group, and their interactions, on the number of male mating partners within the social group, run model model 2. This model run with n = 118 replicates, representing all females that weaned some offspring and whose social group included at least one male. The response variable is Number of male mating partners within the social group. Utilize data from sheet 1, “winter females”. To test prediction (iii) about the potential effects of female serum testosterone levels, female anogenital distance (AGD), and the number of males within the social group, and their interactions, on the number of male mating partners outside the social group, run model model 3. This model run with n = 160 replicates, representing all females that bred effectively. The response variable is Number of male mating partners outside the social group. Utilize data from sheet 1, “winter females”. To test prediction (iv) about the potential effects of female serum testosterone levels, female anogenital distance (AGD), and the number of male mating partners, and their interactions, on the number of offspring weaned, run model model 4. This model run with n = 160 replicates, representing all females that bred effectively. The response variable is the litter size at weaning. Utilize data from sheet 1, “winter females”. Results 3.2. To test prediction (v) about the potential effects of female serum testosterone levels, female anogenital distance (AGD), and their interaction, on the number of offspring weaned by females, run model model 5. This model run with n = 308 replicates, representing all females that bred effectively. The response variable is the litter size at weaning. Utilize data from sheet 2, “spring females”. In all models, year and social group ID (SGID), were random factors. All other factors were considered fixed factors. Serum testosterone does not distribute normally, so it must be included transformed with Log10. Female body weight during mating and nursing season must be included transformed with LN. Model fits were assessed with quantile residual dispersion. The best models were chosen by their AICc values and average model weight. Description of the data and file structure **The file contains two sheets:** **Sheet 1** named “winter females” should be used to run models 1,2,3 and 4. **Sheet 2** named “spring females” should be used to run model 5. Variables included: Year (individual variable). Degu ID: Ear tag number or degu identity. In sheet 1, “winter females” two females are present three times, and 19 females are present two times. In sheet 2, “spring females” three females are present three times, and 33 females are present two times. For these individuals, each data must be considered as independent data (individual variable). Sex: F=female (individual variable). Focal AGD length (mm): is the length of the anogenital distance, expressed in millimeters, of the focal females (individual variable). Body weight (g): is the mean of body weight of focal females (individual variable). LN body weight (g): is log (natural logarithm) transformed body weight. Testosterone level (nmol/L): is the measurement of serum testosterone, expressed in (nmol/L). As the testosterone variable does not have a normal distribution, to work with data, the testosterone variable should be transformed by Log (individual variable). Log10 Testosterone (nmol/L): is log transformed testosterone levels. Group ID (SGID): The number of the social group to which the female degu belonged. Litter size at weaning: is the number of pups that each female produces, measured at weaning (individual variable). Total n° of male mating partners corresponds to the total number of males with which each female produces offspring (individual variable). N° of male mating partners within social group: corresponds to the number of males within the social group, with which each female produces offspring (individual variable). N° of male mating partners outside social group: corresponds to the number of males outside the social group, with which each female produces offspring (individual variable). Id male mating partners: corresponds to the ids of each male mating partner. This variable is not included in the analysis, in any model. Its function is to quantify the number of total couples, inside and outside the social group. Sheet 1, Row J, K, L: Alone = females that were not associated with any social group. Sheet 1, Row Q: WMP=female without male sexual partner. NIF=unidentified father. Genetically is a different male mating partner, that was not identified in the registry of animals for which we have genetic material data. It possibly corresponds to a male that was not captured and therefore does not have a DNA sample. ## Code/software Analyses were performed in R 4.1.3 (R Core Team 2022). Linear mixed models (LMM) were fitted with the package LME4 1.1-31. DHARMa 0.4.6 and MuMIn 1.46.0 packages were used to perform residual diagnostics and model selection routines, respectively.