Data from: Oviposition-induced plant volatiles prime defences against impending herbivores in neighbouring non-damaged plants (doi.org/10.1038/s41598-025-02371-7)

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.

Abstract

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.