Location: Soybean and Nitrogen Fixation ResearchTitle: The effects of drought and herbivory on plant–herbivore interactions across 16 soybean genotypes in a field experiment Author
Submitted to: Ecological Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/13/2013
Publication Date: 6/1/2013
Citation: Grinnan, R., Carter Jr, T.E., Johnson, M. 2013. The effects of drought and herbivory on plant–herbivore interactions across 16 soybean genotypes in a field experiment. Ecological Entomology. Vol. 38, No. 3, pp. 290-302. Interpretive Summary: Most climate change models predict increased variability in precipitation around the globe. It is generally accepted that drought will become more common in many areas. Understanding how plants and insects will jointly respond to climate change is important to agriculture. It has been hypothesized that increased drought could increase the frequency and severity of insect population outbreaks. If true, the negative effects of drought on plants could be exacerbated by insect damage. It is therefore imperative to understand how the combined effects of drought and damage by herbivorous insects might affect crop performance. Identifying traits that protect crop plants from abiotic and biotic stresses is critical to building predictive models for plant and insect responses to climate. This research investigates how drought and an experimentally created insect herbivore population outbreak affect plant–herbivore interactions, and whether or not any genetically variable plant traits could predict a plant's response to both drought and herbivory in a model crop system, soybean. To address these goals, we conducted a field experiment in which we asked the following question, "how do the combined effects of drought and herbivory affect soybean performance." We discuss the implications of our results in the context of the potential effects of climate change on agroecosystems.
Technical Abstract: As the Earth’s climate continues to change, drought and insect population outbreaks are predicted to increase in many parts of the world. It is therefore important to understand how changes in such abiotic and biotic stressors might impact agroecosystems. 16 soybean genotypes were tested in a field experiment to determine: (i) the combined effects of drought and herbivory on plant performance, and (ii) the impact of drought on soybean resistance to herbivores. It was found that drought had a greater effect on soybean performance than herbivory, and drought and herbivory did not interact to impact on any measure of plant performance. Drought caused decreased insect herbivory on average. These results suggest that, although the effects of climate-associated changes in drought and herbivory will have negative effects on soybean, these potential effects are quantifiable with simple experiments and can be mitigated through continued breeding of varieties that are tolerant and resistant to these abiotic and biotic stressors.