van Doan Cong, Pfander Marc, Guyer Anouk S, Zhang Xi, Maurer Corina, Robert Christelle A M
Institute of Plant Sciences University of Bern Bern Switzerland.
Oeschger Centre for Climate Change Research (OCCR) University of Bern Bern Switzerland.
Ecol Evol. 2021 Mar 16;11(9):4182-4192. doi: 10.1002/ece3.7314. eCollection 2021 May.
Climate change will profoundly alter the physiology and ecology of plants, insect herbivores, and their natural enemies, resulting in strong effects on multitrophic interactions. Yet, manipulative studies that investigate the direct combined impacts of changes in CO, temperature, and precipitation on the third trophic level remain rare. Here, we assessed how exposure to elevated CO, increased temperature, and decreased precipitation directly affect the performance and predation success of species from four major groups of herbivore natural enemies: an entomopathogenic nematode, a wolf spider, a ladybug, and a parasitoid wasp. A four-day exposure to future climatic conditions (RCP 8.5), entailing a 28% decrease in precipitation, a 3.4°C raise in temperature, and a 400 ppm increase in CO levels, slightly reduced the survival of entomopathogenic nematodes, but had no effect on the survival of other species. Predation success was not negatively affected in any of the tested species, but it was even increased for wolf spiders and entomopathogenic nematodes. Factorial manipulation of climate variables revealed a positive effect of reduced soil moisture on nematode infectivity, but not of increased temperature or elevated CO. These results suggest that natural enemies of herbivores may be well adapted to short-term changes in climatic conditions. These findings provide mechanistic insights that will inform future efforts to disentangle the complex interplay of biotic and abiotic factors that drive climate-dependent changes in multitrophic interaction networks.
气候变化将深刻改变植物、植食性昆虫及其天敌的生理和生态,对多营养级相互作用产生重大影响。然而,研究二氧化碳、温度和降水变化对第三营养级直接综合影响的操控性研究仍然很少。在此,我们评估了暴露于高浓度二氧化碳、温度升高和降水减少的环境如何直接影响植食性动物四大类天敌的表现和捕食成功率:一种昆虫病原线虫、一只狼蛛、一只瓢虫和一只寄生蜂。在未来气候条件(代表性浓度路径8.5)下暴露四天,降水量减少28%,温度升高3.4℃,二氧化碳浓度增加400ppm,这略微降低了昆虫病原线虫的存活率,但对其他物种的存活率没有影响。在任何测试物种中,捕食成功率都没有受到负面影响,但狼蛛和昆虫病原线虫的捕食成功率甚至有所提高。对气候变量的析因操控显示,土壤湿度降低对线虫感染性有积极影响,但温度升高或二氧化碳浓度升高则没有。这些结果表明,食草动物的天敌可能很好地适应了气候条件的短期变化。这些发现提供了机制性见解,将为未来解析驱动多营养级相互作用网络中气候依赖性变化的生物和非生物因素复杂相互作用的努力提供参考。