Abstract:
Both sexually selected traits and mate preferences for these traits can be context dependent, yet how variation in preferred traits could select for context dependent preferences has rarely been examined. The signal reliability hypothesis predicts that mate preferences vary across contexts (e.g., environments) in relation to the reliability of the information preferred traits provide in those contexts. Extensive variation in copy number of mc4r B alleles on the Y-chromosome that associates with male size in Xiphophorus multilineatus allowed us to use a split-sibling design to determine if male size is more likely to provide information about male genotype (i.e., dam) when males were reared in a warm as compared to a cold environment. We then examined strength of preference for male size by females reared in the same two environments. We found that males were larger in the cold environment, but male size was more variable across dams in the warm environment, and therefore male size would be a more reliable indicator of dam (i.e., genetics) in the warm environment. Females reared in the warm environment had stronger mate preferences based on male size than cold reared females, with a significant influence of dam on strength of preference. Therefore, strength of female preference for male size was influenced by the temperature in which they were reared, with the direction of the difference across treatments supporting the signal reliability hypothesis. Understanding how the reliability of male traits can select for contextual variation in the strength of the female mate preferences will further our discovery of adaptive mate preferences. For example, a relationship between the strength of a female\'s mate preference and their growth rates was detected in the context where females had a preference based on male size, supporting a hypothesis from previous work with this species of disassortative mating in relation to growth rates to mitigate a documented growth-mortality tradeoff.
摘要:
性选择的特征和对这些特征的伴侣偏好都可以取决于上下文,然而,很少研究偏好特征的变异如何选择上下文相关的偏好。信号可靠性假设预测伴侣偏好在不同的环境中变化(例如,环境)与在这些上下文中提供的信息首选特征的可靠性有关。Y染色体上mc4rB等位基因的拷贝数的广泛变化与Shiphophorus的雄性大小相关,使我们能够使用分裂同胞设计来确定雄性大小是否更有可能提供有关雄性基因型的信息(即,大坝),与寒冷的环境相比,雄性在温暖的环境中饲养。然后,我们检查了在相同的两种环境中饲养的雌性对雄性大小的偏爱强度。我们发现在寒冷的环境中雄性较大,但是在温暖的环境中,不同水坝的男性体型差异更大,因此,男性的体型将是一个更可靠的大坝指标(即,遗传学)在温暖的环境中。在温暖环境中饲养的雌性比寒冷饲养的雌性具有更强的基于雄性大小的伴侣偏好,大坝对偏好强度有显著影响。因此,女性对男性体型的偏好强度受到饲养温度的影响,不同治疗方法的差异方向支持信号可靠性假设。了解男性特征的可靠性如何选择女性伴侣偏好强度的上下文变化,将进一步发现适应性伴侣偏好。例如,在女性有基于男性大小的偏好的背景下,检测到女性伴侣偏好的强度与其生长速度之间的关系,支持先前关于该物种的相异交配与增长率有关的假设,以减轻记录在案的生长-死亡率权衡。