DOI: 10.5061/dryad.t815g
title: Data from: Pest tradeoffs in technology: reduced damage by caterpillars in Bt cotton benefits aphids

description: The rapid adoption of genetically engineered (GE) plants that express
 insecticidal Cry proteins derived from Bacillus thuringiensis (Bt) has
 raised concerns about their potential impact on non-target organisms. This
 includes the possibility that non-target herbivores develop into pests.
 Although studies have now reported increased populations of non-target
 herbivores in Bt cotton, the underlying mechanisms are not fully
 understood. We propose that lack of herbivore-induced secondary
 metabolites in Bt cotton represents a mechanism that benefits non-target
 herbivores. We show that, because of effective suppression of Bt-sensitive
 lepidopteran herbivores, Bt cotton contains reduced levels of induced
 terpenoids. We also show that changes in the overall level of these
 defensive secondary metabolites are associated with improved performance
 of a Bt-insensitive herbivore, the cotton aphid, under glasshouse
 conditions. These effects, however, were not as clearly evident under
 field conditions as aphid populations were not correlated with the amount
 of terpenoids measured in the plants. Nevertheless, increased aphid
 numbers were visible in Bt cotton compared with non-Bt cotton on some
 sampling dates. Identification of this mechanism increases our
 understanding of how insect-resistant crops impact herbivore communities
 and helps underpin the sustainable use of GE varieties.
description: Aphids“Aphids” contains two
 sheets one given the aphid population of all plants used in the
 experiment, while the second contains the average hind tibia length in mm
 of aphids from each plantHeliothis and Plant
 Damage“Heliothis and Plant
 Damage” contains two sheets, one given the survivial and weight in mg of
 H. virescens on Bt an non-Bt cotton. The second the leaf damage in cm2
 caused by H. virescens on both plant types. NOTE: The lower number of data
 entries in the plant damage sheet is caused by loss of raw data due to a
 camera malfunction.Gossypol content in
 response to H. virescens“Gossypol content in
 response to H. virescens “ gives the terpenoid concentrations of oldest
 and youngest leaf of Bt and non-Bt cotton that were uninfested or infested
 with H. virescens for one week. All data is ng/terpenoids per mg dry
 weight leaf. NOTE: Terpenoid data from our field study is included in the
 Field Experiment data sheets to ease comparison of
 data.Gossypol content in
 response to Jasmonic Acid“Gossypol content in
 response to Jasmonic Acid” gives the terpenoid concentrations of oldest
 and youngest leaf of Bt and non-Bt cotton that were untreated or treated
 with Jasmonic acid one week before collecting the leaf. All data is
 ng/terpenoids per mg dry weight leaf. NOTE: Terpenoid data from our field
 study is included in the “Field Experiment” folder to ease comparison of
 data.Summary_Plants infested
 with Spodoptera“Summary_Plants infested
 with Spodoptera” contains the data of the field experiment plants there
 were artifically infested with S. exigua. The File contain three sheets
 detailing the aphid population per plant and sample date, the damage of
 each plant per screening data and the final terpenoid concentration of
 each plant at the end of the experiment. NOTE: Plant identifiers are
 consistent for each data set. Missing entries are caused by problems
 during data collection, e.g. corrupted or blurred jpeg files during plant
 damage assessment.Summary_Plants naturally
 infested“Summary_Plants
 naturally infested” contains the data of the field experiment plants that
 were only exposed to natural infestation. Both files contain three sheets
 detailing the aphid population per plant and sample date, the damage of
 each plant per screening data and the final terpenoid concentration of
 each plant at the end of the experiment. NOTE: Plant identifiers are
 consistent for each data set. Missing entries are caused by problems
 during data collection, e.g. corrupted or blurred jpeg files during plant
 damage assessment.