In polygynous ungulates, males invest time and energy to reproductive activities during the rut and this involvement is expected to increase with age due to different mating tactics in young versus adult males. In contrast, mating period is expected to be less costly for females for which late gestation and lactation are the most energetically demanding periods. However, empirical supports of these hypotheses through direct measures of reproductive effort are still limited in ungulate species, particularly in males. In addition, this general pattern may be modified in populations facing selective harvesting on adult males, where young males may experience less competition to mate and invest more energy during the rut. We investigated these hypotheses by studying the age- and sex-specific variations of kidney fat reserves from pre- to post-rut periods in a trophy-hunted population of Mediterranean mouflon (Ovis gmelini musimon × Ovis sp.), a polygynous dimorphic mountain ungulate. Females were found to build up energy from the pre-rut to the post-rut periods, most likely to face with the subsequent costs of gestation/lactation that occur few months later. Conversely, kidney fat mass strongly decreased similarly in both young and mature males, and with the same magnitude, suggesting a strong investment of males of all ages in this population. This might be related to the selective hunting pressure on mature males this population is facing with. This result supports the need for more empirical and comparative studies to better grasp the influence of trophy hunting on reproductive effort in male ungulates.

中文翻译：

---

年轻和成熟的雄性在地中海欧洲盘羊的战利品狩猎种群发情期间具有相似的能量消耗

在一夫多妻的有蹄类动物中，雄性在发情期间将时间和精力投入到生殖活动中，并且由于年轻雄性和成年雄性的交配策略不同，这种参与预计会随着年龄的增长而增加。相比之下，对于妊娠晚期和哺乳期是能量需求最高的时期的雌性来说，预计交配期的成本较低。然而，通过直接测量繁殖努力对这些假设的经验支持在有蹄类动物中仍然有限，尤其是在雄性中。此外，在成年雄性面临选择性收获的种群中，这种一般模式可能会发生改变，在这些群体中，年轻雄性可能会在交配期间经历较少的交配竞争并投入更多能量。我们通过研究地中海欧洲盘羊（Ovis gmelini musimon × Ovis sp.）（一种一夫多妻的二形山地有蹄类动物）的战利品狩猎种群中肾脏脂肪储备从车辙前到车辙后的年龄和性别特异性变化来研究这些假设. 发现雌性从发情前到发情后时期积累能量，最有可能面临几个月后发生的妊娠/哺乳期的后续成本。相反，年轻和成熟男性的肾脏脂肪量类似地显着下降，并且幅度相同，表明所有年龄段的男性都对该人群进行了大量投资。这可能与该种群面临的成熟雄性面临的选择性狩猎压力有关。