Neuropeptide manipulation has behavioural and cascading fitness consequences in wild-living fish

Due to the difficulty of simultaneously assessing variation in individual physiology, behaviour and fitness, we often know little about the mechanistic basis of life-history trade-offs and fitness variation. It is similarly challenging to examine how physiological variation in one individual has cascading fitness consequences for others in the social environment. Using a wild-living fish (ocellated wrasse, Symphodus ocellatus), we manipulated a neuropeptide pathway associated with courtship, aggression and parental care in vertebrates (arginine vasotocin, AVT) and directly examined the behavioural and fitness consequences. Nesting males injected with the AVT antagonist increased their paternal care, resulting in increased hatching of offspring and increased reproductive success of all individuals that mated at his nest. By directly examining physiology, behaviour and reproductive success, we revealed how a small change in individual physiology has clear and direct fitness consequences for multiple individuals.

鉴于个体生理、行为与适应度的同时评估之难度，我们往往对生命史权衡与适应度变异的机制基础知之甚少。同样，探究个体生理变异如何在社会环境中对其他个体的适应度产生连锁效应亦颇具挑战。通过采用野生生活鱼类（眼斑隆头鱼，Symphodus ocellatus）作为研究对象，我们操控了与脊椎动物求偶、攻击性和亲子关怀相关的神经肽途径（精氨酸加压素，AVT）并直接考察了其行为与适应度后果。注射AVT拮抗剂的筑巢雄性个体增加了其父性关怀，进而导致后代孵化率的提升及与其巢穴交配的所有个体的繁殖成功率提高。通过直接考察生理、行为与繁殖成功，我们揭示了个体生理的微小变化如何对多个个体产生明确且直接的适应度后果。