DOI: 10.5061/dryad.69p8cz99c
title: Data from: Oviposition-induced plant volatiles prime defences against impending herbivores in neighbouring non-damaged plants

description: Plants exploit environmental cues about the risks of encountering insect
 herbivores, often sensitising defensive responses. While herbivore-induced
 plant volatiles (HIPVs) are reported to enhance plant defences against
 incoming herbivores, responses to oviposition-induced plant volatiles
 (OIPVs) are massively under-explored. We studied whether OIPV emissions
 from Brassica napus enhance defences in non-damaged neighbouring B. napus
 when subsequently infested with Pieris brassicae larvae. We collected and
 analysed emission rates of plant volatile organic compounds under
 different treatments and measured P. brassicae larvae biomass as a proxy
 for defence. We show that oviposition triggers the release of specific
 volatiles, i.e. α-pinene, dimethyl-trisulfide, and limonene, potentially
 serving as herbivore early warning cues for neighbouring non-damaged
 plants. Initially, after three days of herbivory, OIPV-receivers emitted
 lower levels of volatiles compared to control receivers; however,
 following seven days of herbivory, both control and OIPV-receivers emitted
 similar amounts of volatiles. We suggest a potential trade-off between
 direct and indirect defences, with sensitised plants investing metabolic
 resources initially towards direct and later enhancing indirect defences.
 We show that OIPVs mediate plant-plant communication, a natural potential
 for Brassicaceae crop protection.
description: # Data from: Oviposition-induced plant volatiles prime defences against
 impending herbivores in neighbouring non-damaged plants Dataset DOI:
 [10.5061/dryad.69p8cz99c](10.5061/dryad.69p8cz99c) ## Description of the
 data and file structure This dataset originates from an experimental study
 investigating plant volatile-mediated interactions between winter rapeseed
 (Brassica napus BRV703) and the large cabbage white butterfly (*Pieris
 brassicae*). The study aimed to analyse the impact of oviposition-induced
 plant volatiles (OIPVs) on plant defence priming against caterpillars. The
 dataset includes volatile organic compound (VOC) measurements and larval
 performance data. Plants (4-5 weeks old) were assigned to four treatment
 groups. The abbreviations used in the dataset were changed in the
 manuscript for simplicity. * Egg-infested plants (Em, written as E in the
 manuscript): Exposed to P. brassicae eggs. * OIPV-receiver plants (Re,
 written as RE in the manuscript): Exposed to volatiles from egg-infested
 plants. * Constitutive volatile receiver plants (Rc, written as RC in the
 manuscript): Exposed to volatiles from non-damaged plants. * Control
 plants (Co, written as C in the manuscript): Non-damaged plants emitting
 constitutive volatiles. Butterflies lay ~30 eggs per plant, and excess
 eggs were removed. Plants were arranged to maintain a 100 cm distance
 between treatment groups to minimise cross-contamination of volatiles. ###
 Defence Priming and Larval Performance Bioassay
 (herbivore_performance_15_03-13_06-2023.xlsx file) On day five, following
 egg incubation, eggs hatched, and neonate larvae were introduced to plants
 to test the effects of defence priming. Larvae were placed on the
 fourth-highest leaf of each plant, and larval biomass was recorded three
 and seven days post-inoculation using a microbalance. The initials used in
 the **herbivore_performance_15_03-13_06-2023** file are; Sample label =
 Treatments G = group of plant treatment G2 = plants with herbivore feeding
 for three days G3 = plants with herbivore feeding for seven days Em =
 Egg-infested plants (emitter of oviposition-induced plant volatiles) Re =
 Receiver of oviposition-induced plant volatiles Rc = Receiver of uninduced
 plant volatiles P = Position of the plant during the experiment Nb_day =
 number of days allowed for herbivore feeding Plant_id = the identity of
 each plant replicates Larval_weight = the biomass of each larvae
 shoot-weight = the aboveground tissue biomass of each plant Cells left
 blank indicate missing values. Missing values occur because measurements
 were not taken and were not applicable for those samples ## Volatile
 Collection and Analysis
 (Identity_of_Volatile_Organic_Compounds_final_15_03-13_06-2023.csv and
 Volatile_Organic-Compounds_final_standardized_15_03-13_06-2023.csv files)
 Volatiles were collected using a push-pull air sampling system with Tenax
 TA adsorbent cartridges. We analysed the samples using gas
 chromatography-mass spectrometry (GC-MS). The dataset includes volatile
 emission profiles from different plant treatments, both before and after
 larval feeding. Volatile identification was conducted using the NIST
 library and confirmed with chemical standards where applicable. ##
 Statistical Analyses ### Multivariate and Univariate Analyses of VOC
 Profiles * Partial least squares discriminant analysis (PLS-DA): Used to
 analyse volatile profile variations between plant treatments with external
 validation. * Kruskal-Wallis and Wilcoxon tests: Applied for univariate
 comparisons of individual volatile emissions. * Linear models: Used for
 total volatile comparisons between treatments. ### Larval Performance
 Analysis * Caterpillar biomass was modelled as a function of plant
 treatment. * Tukey’s HSD test: Used for multiple comparisons. *
 Wilcoxon-signed-rank test: Applied for non-parametric analyses where
 normality assumptions were not met. ## Data Files *
 herbivore_performance_15_03-13_06-2023: Contains larval biomass
 measurements over time. *
 Volatile_Organic-Compounds_final_standardized_15_03-13_06-2023: Contains
 volatile emission data (pg.g⁻¹) for each plant treatment. *
 Identity_of_Volatile_Organic_Compounds_final_15_03-13_06-2023: Provides a
 detailed list of identified volatiles. ## Software and Dependencies * R
 (v4.2.2) for data processing and statistical analysis. * xcms package for
 volatile data processing. * Caret package for PLS-DA modelling. * emmeans
 package for linear model comparisons.