DOI: 10.5061/dryad.1vhhmgr4q
title: Glucosinolate induction by parasitized caterpillars

description: Herbivore feeding damage induces increased production of chemical defenses
 in many plants and the amount of induction is often correlated with the
 amount of feeding damage. Many parasitoids are thought to increase plant
 fitness by decreasing herbivore feeding in the near term or reducing
 herbivore populations in the long term, making defenses which negatively
 impact parasitoids typically disadvantageous for the plant. Solitary
 parasitoids (where only one individual completes development per host)
 generally cause their hosts to feed less than unparasitized herbivores.
 However, gregarious parasitoids (where more than one individual develops
 per host) can decrease plant fitness if parasitized herbivores feed more
 than unparasitized herbivores, which should then also induce greater
 defense chemistry. Yet, it is unclear whether differential induction
 effects are primarily due to differences in feeding amount or parasitoid
 identity. We explored the relationship between plant defense induction and
 caterpillars parasitized by a solitary versus a gregarious parasitoid. We
 wanted to determine whether: 1) caterpillars parasitized by a gregarious
 parasitoid induced higher concentrations of chemical defense and 2)
 differential responses to feeding by herbivores parasitized by different
 parasitoids were based on differences in the amount of feeding damage or
 the identity of parasitoids developing within the parasitized
 caterpillars. We measured the induction of glucosinolate defenses in
 Brassica rapa using Pieris rapae caterpillars of equivalent size and
 development stage parasitized by either a solitary (Cotesia rubecula) or a
 gregarious (C. glomerata) parasitoid. We demonstrate that C.
 glomerata-parasitized P. rapae elicit an increase in glucosinolate
 production independent of the amount of feeding damage, suggesting
 qualitative rather than quantitative differences in feeding damage are
 responsible for the observed patterns. Our results indicate that plants
 can differentially induce chemical defenses in response to the identity of
 a parasitoid inside an herbivore and demonstrate the importance of
 parasitoid identity in determining plant defense expression.
description: # Glucosinolate induction by parasitized caterpillars
 [https://doi.org/10.5061/dryad.1vhhmgr4q](https://doi.org/10.5061/dryad.1vhhmgr4q) ## Description of the data and file structure Data on caterpillar fitness, plant damage, and glucosinolate content for plants fed on by caterpillars parasitized by different parasitoid wasps. Plants were fed on by caterpillars for three days with leaves being analyzed for glucosinolate content before and after feeding damage. Leaf content was analyzed with HPLC-PDA and leaf damage was quantified using ImageJ to measure area. ### Files and variables #### File: induction\_full\_data\_csv\_dryad.csv **Description:** Caterpillar fitness data and glucosinolate content of plants after feeding by parasitized and unparasitized caterpillars (primary experiment in manuscript); missing/blank data indicated by "NA" ##### Variables * Treatment: Cr4 (Cotesia rubecula-parasitized 4th instar), Cg4 (Cotesia glomerata-parasitized 4th instar), Cg5 (C. glomerata-parasitized 5th instar), Pr4 (unparasitized Pieris rapae 4th instar), Pr5 (unparasitized P. rapae 5th instar) * Replicate: Replicate numbers * Plant Species: rapa = Brassica rapa, numbers are accessions/populations of B. rapa received from USDA-GRIN * Plant date: data of planting * Date pre: date of pre-feeding leaf analysis * Date post: date of post-feeding leaf analysis * Larva mass pre (mg): caterpillar mass before feeding (milligrams) * Larva mass post: caterpillar mass after feeding (milligrams) * 1.27 cm2 (.5 in) leaf mass (g): Mass of standard 1.27-cm^2 leaf disc for subsequent calculations * Damage area (cm2): Area of feeding damage (square centimeters) * Damage mass (mg): Calculated mass of leaf area fed on * pre leaf mass: mass (mg) of leaf sample for pre-feeding analysis * post leaf mass: mass (mg) of leaf sample for post-feeding analysis  * parasitized: Y/N if confirmed parasitized * notes: additional observation notes * pre Injection vol: volume of LC injection for pre-feeding sample (microliters) * post Injection vol: volume of LC injection for post-feeding sample (microliters) * Sin std factor: multiplication factor for standard used in sample for LC calculations * Sinigrin UV1: LC-PDA reading for sinigrin pre-feeding sample * Progoitrin UV1: LC-PDA reading for progoitrin pre-feeding sample * Sinalbin UV1: LC-PDA reading for sinalbin pre-feeding sample * Glucoalyssin UV1: LC-PDA reading for glucoalyssin pre-feeding sample * Gluconapin UV1: LC-PDA reading for gluconapin pre-feeding sample * Glucocochlearin UV1: LC-PDA reading for glucocochlearin pre-feeding sample * Glucobrassicanapin UV1: LC-PDA reading for glucobrassicanapin pre-feeding sample * Glucobrassicin UV1: LC-PDA reading for glucobrassicin pre-feeding sample * 4-methoxy: LC-PDA reading for 4-methoxyglucobrassicin pre-feeding sample * Neoglucobrassicin: LC-PDA reading for neoglucobrassicin pre-feeding sample * Sinigrin UV2: LC-PDA reading for sinigrin post-feeding sample * Progoitrin UV2: LC-PDA reading for progoitrin post-feeding sample * Sinalbin UV2: LC-PDA reading for sinalbin post-feeding sample * Glucoalyssin UV2: LC-PDA reading for glucoalyssin post-feeding sample * Gluconapin UV2: LC-PDA reading for gluconapin post-feeding sample * Glucocochlearin UV2: LC-PDA reading for glucocochlearin post-feeding sample * Glucobrassicanapin UV2: LC-PDA reading for glucobrassicanapin post-feeding sample * Glucobrassicin UV2: LC-PDA reading for glucobrassicin post-feeding sample * 4-methoxy UV2: LC-PDA reading for 4-methoxyglucobrassicin post-feeding sample * Neoglucobrassicin UV2: LC-PDA reading for neoglucobrassicin pre-feeding sample * Sinigrin MS2: LC-MS sinigrin reading (not used) * SIN UV pre: Calculated content of sinigrin in pre-feeding sample * SIN UV post: Calculated content of sinigrin in post-feeding sample * PRO UV pre: Calculated content of progoitrin in pre-feeding sample * PRO UV post: Calculated content of progoitrin in post-feeding sample * SNB UV pre: Calculated content of sinalbin in pre-feeding sample * SNB UV post: Calculated content of sinalbin in post-feeding sample * GAL UV pre: Calculated content of glucoalyssin in pre-feeding sample * GAL UV post: Calculated content of glucoalyssin in post-feeding sample * GNP UV pre: Calculated content of gluconapin in pre-feeding sample * GNP UV post: Calculated content of gluconapin in post-feeding sample * GCC UV pre: Calculated content of glucocochlearin in pre-feeding sample * GCC UV post: Calculated content of glucocochlearin in post-feeding sample * GBN UV pre: Calculated content of glucobrassicanapin in pre-feeding sample * GBN UV post: Calculated content of glucobrassicanapin in post-feeding sample * GBR UV pre: Calculated content of glucobrassicin in pre-feeding sample * GBR UV post: Calculated content of glucobrassicin in post-feeding sample * MET UV pre: Calculated content of 4-methoxyglucobrassicin in pre-feeding sample * MET UV post: Calculated content of 4-methoxyglucobrassicin in post-feeding sample * NGB UV pre: Calculated content of neoglucobrassicin in pre-feeding sample * NGB UV post: Calculated content of neoglucobrassicin in post-feeding sample #### File: GS\_data\_dissections\_dryad.csv **Description:** Dissections of parasitized caterpillars fed different host plants (experiment 2 in manuscript); missing/blank data indicated by "NA" ##### Variables * parasitoid: Cr = Cotesia rubecula, Cg = Cotesia glomerata * plant: plant host caterpillar fed on; rapa = Brassica rapa, collards = Brassica oleracea (geogia southern collards), fresh = caterpillar dissected immediately after parasitism (no feeding) * cgl: number of C. glomerata larvae * encaps: encapsulation observed (y/n) ## Code/software No special software needed to view the data ## Access information Other publicly accessible locations of the data: * None Data was derived from the following sources: * NA