Insect herbivores are frequently reported to metabolize plant defense compounds, but the physiological and ecological consequences are not fully understood. It has rarely been studied whether such metabolism is genuinely beneficial to the insect, and whether there are any effects on higher trophic levels. Here, we manipulated the detoxification of plant defenses in the herbivorous pest diamondback moth (Plutella xylostella) to evaluate changes in fitness, and additionally examined the effects on a predatory lacewing (Chrysoperla carnea). Silencing glucosinolate sulfatase genes resulted in the systemic accumulation of toxic isothiocyanates in P. xylostella larvae, impairing larval development and adult reproduction. The predatory lacewing C. carnea, however, efficiently degraded ingested isothiocyanates via a general conjugation pathway, with no negative effects on survival, reproduction, or even prey preference. These results illustrate how plant defenses and their detoxification strongly influence herbivore fitness but might only subtly affect a third trophic level.
All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for figures and figure supplements.
- Ruo Sun
- Ruo Sun
- Xingcong Jiang
- Michael Reichelt
- Jonathan Gershenzon
- Sagar Subhash Pandit
- Daniel Giddings Vassão
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
- Daniel J Kliebenstein, University of California, Davis, United States
© 2019, Sun et al.
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