Aging alters interspecific competition between two sympatric insect-parasitic nematode species

Interspecific competition can vary depending on the stage, age, or physiological state of the competitors. Competitive ability often increases with age or size; alternatively, senescence can lead to a loss of viability and reduced competitive success. Differences between species in their age-specific competitive abilities can promote coexistence in the face of substantial niche overlap. We examined two sympatric species of nematodes (genus Steinernema) to determine whether their competitive relationship changes as a function of age. These obligately killing insect parasites are known for their broad host ranges and are transmitted from insect to insect via a juvenile stage propagule that is free-living in the soil. Here, we tested whether the two species differed in the effects of age by examining the mortality of insect hosts infected with young or old transmission stage nematodes of each species. We also performed mixed infections, where an equal ratio of both species was simultaneous...种间竞争会随竞争者的发育阶段、年龄或生理状态发生变化。竞争能力通常随年龄或体型增长而提升；与之相反，衰老会导致生存力下降，进而降低竞争成功率。不同物种间的年龄特异性竞争能力差异，即便面对显著的生态位重叠，也能促进物种共存。本研究以两种同域分布的斯氏线虫属（Steinernema）线虫为研究对象，旨在探究其竞争关系是否随年龄发生改变。这类专性致死性昆虫寄生虫以宽泛的寄主范围闻名，它们通过在土壤中自由生活的幼态繁殖体在昆虫个体间传播。本研究通过检测感染各物种年轻与老龄传播阶段线虫的昆虫宿主死亡率，验证两种线虫在年龄效应上是否存在差异。我们还开展了混合感染实验，即将两个物种以相同比例同时……