Albittar Loulou, Ismail Mohannad, Lohaus Gertrud, Ameline Arnaud, Visser Bertanne, Bragard Claude, Hance Thierry
Biodiversity Research Centre, Earth and Life Institute, UCLouvain, 1348, Louvain-la-Neuve, Belgium.
Molecular Plant Science/Plant Biochemistry, Bergische Universität Wuppertal, 42119, Wuppertal, Germany.
Oecologia. 2019 Sep;191(1):113-125. doi: 10.1007/s00442-019-04467-0. Epub 2019 Jul 24.
Effects of plants on herbivores can cascade up the food web and modulate the abundance of higher trophic levels. In agro-ecosystems, plant viruses can affect the interactions between crops, crop pests, and natural enemies. Little is known, however, about the effects of viruses on higher trophic levels, including parasitoids and their ability for pest regulation. We tested the hypothesis that a plant virus affects parasitoid foraging behaviour through cascading effects on higher trophic levels. We predicted that the semi-persistent Beet yellows virus (BYV) would influence plant (Beta vulgaris) quality, as well as aphid host (Aphis fabae) quality for a parasitoid Lysiphlebus fabarum. We determined amino acid and sugar content in healthy and infected plants (first trophic level), lipid content and body size of aphids (second trophic level) fed on both plants, as well as foraging behaviour and body size of parasitoids (third trophic level) that developed on aphids fed on both plants. Our results showed that virus infection increased sugars and decreased total amino acid content in B. vulgaris. We further observed an increase in aphid size without modification in host aphid quality (i.e., lipid content), and a slight effect on parasitoid behaviour through an increased number of antennal contacts with host aphids. Although the BYV virus clearly affected the first two trophic levels, it did not affect development or emergence of parasitoids. As the parasitoid L. fabarum does not seem to be affected by the virus, we discuss the possibility of using it for the development of targeted biological control against aphids.
植物对食草动物的影响会在食物网中产生级联效应，并调节较高营养级的数量。在农业生态系统中，植物病毒会影响作物、作物害虫和天敌之间的相互作用。然而，关于病毒对包括寄生蜂及其害虫调控能力在内的较高营养级的影响，我们所知甚少。我们检验了一种植物病毒通过对较高营养级的级联效应影响寄生蜂觅食行为的假设。我们预测，半持久性的甜菜黄化病毒（BYV）会影响植物（甜菜）的质量，以及蚜虫寄主（豆蚜）对寄生蜂豌豆蚜茧蜂的质量。我们测定了健康和受感染植物（第一营养级）中的氨基酸和糖含量、取食这两种植物的蚜虫（第二营养级）的脂质含量和体型，以及在取食这两种植物的蚜虫上发育的寄生蜂（第三营养级）的觅食行为和体型。我们的结果表明，病毒感染增加了甜菜中的糖分并降低了总氨基酸含量。我们进一步观察到蚜虫体型增大，但寄主蚜虫质量（即脂质含量）未改变，并且通过增加与寄主蚜虫的触角接触次数对寄生蜂行为产生了轻微影响。尽管BYV病毒明显影响了前两个营养级，但它并未影响寄生蜂的发育或羽化。由于豌豆蚜茧蜂似乎不受该病毒影响，我们讨论了将其用于开发针对蚜虫的靶向生物防治方法的可能性。
