Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia.
Centre for Freshwater Ecosystems, La Trobe University, Albury, Victoria, Australia.
J Fish Biol. 2022 Sep;101(3):550-559. doi: 10.1111/jfb.15122. Epub 2022 Jun 21.
Sex-specific reproductive roles contribute to sexual dimorphic morphological trait variations. In uniparental mouth-brooding fishes, the mouth performs a reproductive function in addition to its key roles in feeding and respiration, resulting in the potential for sex-specific functional performance trade-offs. Trait differences related to parental care may occur when the individual matures or be restricted to periods when the parent is mouth-brooding. This study explored sexual dimorphism and morphological trait adaptations related to feeding, breeding, respiration and locomotion performance in two paternal mouth-brooding freshwater fishes (Glossamia aprion and Neoarius graeffei). Eight morphological traits were evaluated for sexual dimorphism (non-brooder males vs. females) and male breeding state differences (brooders vs. non-brooders). Male breeding state was a significant predictor of trait variation in both species. Brooders differed in buccal volume and in several feeding and locomotory traits compared to non-brooder males. Non-brooder males had bigger buccal volumes and relative eye diameters (G. aprion) and larger relative gape sizes (N. graeffei) compared to females, a potential response to both mouth-brooding and feeding requirements. Although there were clear trait differences between brooder and non-brooder males, further research is required to confirm whether individuals return to their former morphology once mouth-brooding has ceased or if trait differences are maintained post-brooding. This study highlights the importance of considering the potential impacts of intraspecific trait variation on the performance of critical life functions, such as feeding, respiration and locomotion across the life history.
性别特异性生殖角色有助于性二态形态特征的变异。在单亲口孵育鱼类中，嘴除了在进食和呼吸方面具有关键作用外，还具有生殖功能，从而导致潜在的性别特异性功能表现权衡。与亲代照顾相关的特征差异可能发生在个体成熟时，也可能仅限于亲代口孵育的时期。本研究探讨了两性异形和与摄食、繁殖、呼吸和运动性能相关的形态特征适应，研究对象为两种雄性口孵育淡水鱼类（Glossamia aprion 和 Neoarius graeffei）。评估了 8 个形态特征的性别二态性（非口孵育雄性与雌性）和雄性繁殖状态差异（口孵育雄性与非口孵育雄性）。雄性繁殖状态是两个物种特征变异的重要预测因子。与非口孵育雄性相比，口孵育雄性在口腔体积和几个摄食和运动特征方面存在差异。与雌性相比，非口孵育雄性具有更大的口腔体积和相对眼径（G. aprion）以及更大的相对口裂大小（N. graeffei），这可能是对口孵育和摄食需求的一种反应。尽管口孵育雄性和非口孵育雄性之间存在明显的特征差异，但需要进一步研究以确认口孵育停止后个体是否会恢复到以前的形态，或者特征差异是否在口孵育后维持。本研究强调了考虑种内特征变异对关键生命功能（如进食、呼吸和运动）性能的潜在影响的重要性，这些功能贯穿整个生命史。
