Mild drought facilitates the increase in wheat aphid abundance by changing host metabolism

Authors: CUI, HONGYING - China Agricultural University; WANG, LEYUN - China Agricultural University; Reddy, Gadi V.P.; ZHAO, ZIHUA - China Agricultural University

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2020
Publication Date: 10/30/2020
Citation: Cui, H., Wang, L., Reddy, G.V., Zhao, Z. 2020. Mild drought facilitates the increase in wheat aphid abundance by changing host metabolism. Annals of the Entomological Society of America. 114(1):79-83. https://doi.org/10.1093/aesa/saaa038.
DOI: https://doi.org/10.1093/aesa/saaa038

Interpretive Summary: Generally, mild drought is more common than severe drought under climate change. The incidence of drought varies in timing and severity among locations and years in relation to the plant growth and development is used as a basis for grouping into different types of drought including severe drought and mild drought. Mild drought has always had insignificant or positive effects on ecological phenotypes and responses. Meanwhile, insect pests such as aphids may benefit from mild droughts due to reduced mortality and more rapid development. To test this hypothesis, the effects of mild drought on wheat plants in association with apterous wheat aphids were examined in the field. Our results indicate that mild drought stress leads to a shift in amino acid composition in plants, which results in higher nutritional quality and larger pest populations. Furthermore, mild drought events are likely to increase in frequency and intensity as a result of climate change. The carrying capacity of the environment with respect to aphids will increase if mild drought events continue to rise in frequency because of climate change. Intentional deficit irrigation is a promising practice to respond to the predicted scarcity of water in the future.

Technical Abstract: Water shortages and water pollution are current issues in ecosystems around the world, and the stress induced by drought can further increase negative impacts on agriculture in these areas. In the present experiment, we examined the effect of mild drought on wheat plants grown in association with the wheat aphid Sitobion avenae Fabricius (Hemiptera: Aphididae) in 2019 and 2020. Using plot experiments, we tested the hypothesis that mild drought tends to enhance the performance of this wheat aphid by changing the nutritional quality of the wheat plants. We found that mild drought treatment significantly increased aphid abundance and population growth rates. Also, mild drought significantly increased total amino acid concentration of the wheat ear as well as concentrations of key amino acids, including Arg, Ile, Leu, Lys, Phe, Try, Gly, Ala, Tyr, and Cys in 2019, and Arg, Ile, Leu, Lys, Gly, and Cys in 2020. Mild drought led to a shift in the composition of amino acids in the plants, causing cascading effects at higher trophic levels. Such changes suggest that the carrying capacity of the environment with respect to aphids will increase if mild drought events continues to increase in frequency with climate change.