Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, United Kingdom.
Ecological Sciences Group, The James Hutton Institute, Invergowrie, Dundee, United Kingdom.
PLoS One. 2019 Jan 11;14(1):e0209965. doi: 10.1371/journal.pone.0209965. eCollection 2019.
The maternal rearing environment can affect offspring fitness or phenotype indirectly via 'maternal effects' and can also influence a mother's behaviour and fecundity directly. However, it remains uncertain how the effects of the maternal rearing environment cascade through multiple trophic levels, such as in plant-insect herbivore-natural enemy interactions. Pea aphids (Acyrthosiphon pisum) show differential fitness on host legume species, while generalist aphid parasitoids can show variable fitness on different host aphid species, suggesting that maternal effects could operate in a plant-aphid-parasitoid system. We tested whether the maternal rearing environment affected the behaviour and fitness of aphids by rearing aphids on two plant hosts that were either the same as or different from those experienced by the mothers. A similar approach was used to test the behaviour and fitness of parasitoid wasps in response to maternal rearing environment. Here, the host environment was manipulated at the plant or plant and aphid trophic levels for parasitoid wasps. We also quantified the quality of host plants for aphids and host aphids for parasitoid wasps. In choice tests, aphids and parasitoid wasps had no preference for the plant nor plant and aphid host environment on which they were reared. Aphid offspring experienced 50.8% higher intrinsic rates of population growth, 43.4% heavier offspring and lived 14.9% longer when feeding on bean plants compared to aphids feeding on pea plants, with little effect of the maternal rearing environment. Plant tissue nitrogen concentration varied by 21.3% in response to aphid mothers' rearing environment, and these differences correlated with offspring fitness. Maternal effects in parasitoid wasps were only observed when both the plant and aphid host environment was changed: wasp offspring were heaviest by 10.9-73.5% when both they and their mothers developed in bean-reared pea aphids. Also, parasitoid wasp fecundity was highest by 38.4% when offspring were oviposited in the maternal rearing environment. These findings indicate that maternal effects have a relatively small contribution towards the outcome of plant-aphid-parasitoid interactions.
母体抚育环境可以通过“母体效应”间接影响后代的适应性或表型，也可以直接影响母亲的行为和繁殖力。然而，目前尚不清楚母体抚育环境如何通过多个营养级（如植物-昆虫食草动物-天敌相互作用）级联影响。豌豆蚜（Acyrthosiphon pisum）在宿主豆科植物上表现出不同的适应性，而泛食性蚜虫寄生蜂在不同的宿主蚜虫物种上适应性也有所不同，这表明母体效应可能在植物-蚜虫-寄生蜂系统中起作用。我们通过在两种与母亲经历相同或不同的宿主植物上饲养蚜虫，来测试母体抚育环境是否影响蚜虫的行为和适应性。同样的方法也被用来测试寄生蜂对母体抚育环境的行为和适应性。在这里，宿主环境是在植物或植物和蚜虫营养级上操纵的。我们还量化了宿主植物对蚜虫和宿主蚜虫对寄生蜂的质量。在选择试验中，蚜虫和寄生蜂对它们被饲养的植物或植物和蚜虫宿主环境没有偏好。与在豌豆植物上取食的蚜虫相比，在豆科植物上取食的蚜虫后代的内禀增长率高 50.8%，后代体重重 43.4%，寿命长 14.9%，而母体抚育环境的影响很小。植物组织氮浓度因蚜虫母亲的抚育环境而异，变化幅度为 21.3%，这些差异与后代适应性相关。只有当改变植物和蚜虫的宿主环境时，寄生蜂才会出现母体效应：当它们和它们的母亲在豆科植物上饲养的豌豆蚜虫中发育时，蜂后代的体重最重可达 10.9-73.5%。此外，当寄生蜂在母体抚育环境中产卵时，其产卵量最高可达 38.4%。这些发现表明，母体效应对植物-蚜虫-寄生蜂相互作用的结果只有相对较小的贡献。
