PDF(Pubmed)
Abstract：
Males and females in sexually dimorphic species show differences in their physiology and behaviour due to differences in energetic investment into reproduction and soma. This means that the two sexes may show different patterns of parasitism at different times of the year. In this study, we evaluate the abundance of fecal eggs and larvae of 5 parasite types (Strongyles, Nematodirus spp., Marshallagia marshalli., Protostrongylus spp. lungworms, and Eimeria spp.) in relation to season and sex in Rocky Mountain bighorn sheep (Ovis canadensis). We use fecal egg counts (FEC) as a proxy for infection intensity. Parasite FECs differed between male and female bighorn sheep and varied with season. We found pronounced fluctuations in fecal egg counts of various parasite species in males and females across different seasons and reproductive stages. Strongyle counts were significantly higher during late gestation and lactation/summer, and particularly pronounced in males. Nematodirus counts were highest during late gestation in females and during the rut in males. Marshallagia counts peaked during late gestation in females and during the rut in males. Protostrongylus spp. lungworm counts were highest during late gestation in females and in males during lactation/summer and the rut. Eimeria oocyst counts varied across seasons, with higher counts in males during the rut and in females during winter and late gestation. Additionally, significant differences in Strongyle counts were observed between coursing and tending rams, with tending rams exhibiting higher counts. We discuss why the sexes might differ in FECs and suggest that differences between FECs of the parasites across seasons may be due to different life cycles and cold tolerance of the parasites themselves.
摘要：
由于对繁殖和躯体的能量投资不同，性二态物种中的雄性和雌性在生理和行为上表现出差异。这意味着男女在一年中的不同时间可能表现出不同的寄生模式。在这项研究中,我们评估了5种寄生虫类型的粪便卵和幼虫的丰度(Strongyles，线虫属。,MarshallagiaMarshalli.,原根菌属。肺虫,和艾美球虫。）与落基山大角羊（Oviscanadensis）的季节和性别有关。我们使用粪便卵数（FEC）作为感染强度的代表。雄性和雌性大角羊之间的寄生虫ECs不同，并且随季节而变化。我们发现，在不同的季节和生殖阶段，雄性和雌性中各种寄生虫的粪便卵数明显波动。在妊娠后期和哺乳期/夏季，粗体体计数显着升高，在男性中尤其明显。在雌性妊娠后期和雄性妊娠期间，线虫的数量最高。Marshallagia计数在雌性妊娠后期和雄性妊娠期间达到顶峰。原根菌属。在哺乳期/夏季和发情期间，雌性和雄性的妊娠后期，肺虫数量最高。艾美耳球虫卵囊计数随季节变化，在车辙期间雄性的计数较高，在冬季和妊娠后期，雌性的计数较高。此外,在奔跑和照料公羊之间观察到Strongyle计数的显着差异，饲养公羊的数量更高。我们讨论了为什么FECs的性别可能不同，并建议跨季节的寄生虫FECs之间的差异可能是由于不同的生命周期和寄生虫本身的耐寒性所致。
