Effects of ambient UV-B radiation on soybean crops: Impact on leaf herbivory by Anticarsia gemmatalis
- Cite this article as:
- Zavala, J., Scopel, A. & Ballaré, C. Plant Ecology (2001) 156: 121. doi:10.1023/A:1012672226811
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Replicated field experiments with large plastic filters were carried outin Buenos Aires (Argentina, 34° S) to study the impacts of current levelsofsolar UV-B radiation (λ ≤ 315 ) on soybean(Glycine max L.) crops and their interactions with chewinginsects, in particular the soybean worm Anticarsiagemmatalis Hübner (Lepidoptera: Noctuidae). Solar(near-ambient)UV-B induced changes in the leaves that reduced their attractiveness toA. gemmatalis larvae in laboratory “choice”bioassays. When the A. gemmatalis larvae were forced toconsume leaves from field plots that received solar UV-B, they grew slightlyless rapidly and suffered more mortality than their counterparts fed withleavesfrom plots covered with polyester films that excluded the UV-B component ofsunlight. Exposure of the larvae themselves to ambient UV-B under a soybeancanopy during the feeding trials did not lower their life expectancy. At thewhole canopy level, we found that solar UV-B exclusion resulted in a two-foldincrease in the number of leaf lesions inflicted by various species of chewinginsects that naturally invaded the field plots. Leaves from canopies exposed tosolar UV-B showed significantly higher levels of soluble phenolics and lowerlevels of lignin than leaves that developed in canopies covered by polyesterfilms. No differences in specific leaf mass, leaf nitrogen or hemicellulosecontent were detected between the control and the solar-UV-B exclusiontreatments. Our results are consistent with the idea that present-day solar UV-B has an important regulatory influence on the interactions between plants and phytophagous insects.