Data from: Salicylate plant defenses reduce aphid nutritional quality and increase predator consumption
Data files
May 18, 2025 version files 100.09 KB
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Plant_defense_Prey_quality_Predation_metasheet.xlsx
92.77 KB
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README.md
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Abstract
Plant-induced defenses can shape multitrophic interactions by affecting herbivore performance and altering their suitability as prey. While the direct effects of these defenses on herbivores are well documented, their indirect consequences— particularly for predator behavior and biological control effectiveness— remain less understood. In our study, we examined how activating salicylic acid (SA)-mediated defenses in tomato plants affects the performance and nutritional quality of the aphid, Macrosiphum euphorbiae, and how this intraspecific variation in aphid quality as prey impacts the predation by the lady beetle predator, Hippodamia convergens. Aphids on SA-treated plants exhibited reduced body mass, protein, and lipid content, indicating lower nutritional value as prey. Correspondingly, we recorded a stronger decline in aphid population on SA-treated plants in the presence of predators. To investigate the effects of reduced aphid quality on predation, we conducted a controlled no-choice assay, which showed that individual lady beetle predators consume more aphids from the SA-treated plants. This increased consumption is consistent with compensatory feeding in response to nutrient-poor prey, although alternative explanations, such as increased prey vulnerability, should also be considered. Our findings demonstrate that SA-mediated defenses can shape predator-prey interactions through bottom-up effects on prey quality and underscore the need to consider these cascading effects when evaluating the ecological impact of plant resistance traits in biological control strategies.
Journal: Ecological Entomology (Accepted)
Manuscript ID: 25-0018-EEN
Authors
- M.S. Bijay Subedi
- Dr. Victoria Marie Pocius
- Ms. Mary Arlin Bunnell
- Ms. Abigail Myers
- Dr. Mônica F. Kersch-Becker
Contact Information
- M.S. Bijay Subedi: beejjus@gmail.com
- Dr. Mônica F. Kersch-Becker: mfkb@psu.edu
Dataset Description
This dataset investigates how SA-mediated plant defenses affect herbivore (aphid) quality and predator (lady beetle) consumption rates. It combines measures of aphid life history traits, body macronutrient profiles, and predator feeding behavior under greenhouse and laboratory conditions.
File Information
Main File:
Plant_defense_Prey_quality_Predation_metasheet.xlsx (Microsoft Excel Workbook)
Sheet Descriptions
Method.2.3_aphid_reproduction
Purpose: Records the reproductive output and survival of individual aphids across control and SA-treated plants.
Measurement: Daily counts of adults and nymphs, cumulative total nymph production, and per-capita nymph production per adult.
Context: Captures how SA-mediated plant defenses affect aphid reproduction during their lifespan (~30 days) under caged conditions.
Method.2.3_lifespan
Purpose: Records aphid survivorship across plant treatments.
Measurement: Time to death (days) for F2 generation nymphs following initial infestation, censored if alive at end.
Context: Allows survival curve analysis comparing aphid lifespan on SA-treated versus control plants.
Method.2.4_biomass
Purpose: Individual aphid body mass measurements.
Measurement: Dry weight (mg) of aphids after nine days of feeding.
Context: Tests if SA-mediated defenses reduce aphid growth and final body size.
Method.2.4_glucose_analysis
Purpose: Aphid glucose content normalized to body mass.
Measurement: Colorimetric glucose assay readings per mg aphid biomass.
Context: Evaluates whether SA treatments alter aphid carbohydrate reserves.
Method.2.4_triglyceride_analysis
Purpose: Aphid triglyceride (lipid) content normalized to body mass.
Measurement: Triglyceride levels from lipid extraction assays per mg aphid biomass.
Context: Determines the effects of plant defense on aphid lipid storage important for energy and reproduction.
Method.2.4_protein_analysis
Purpose: Aphid protein content normalized to body mass.
Measurement: Bradford assay-derived protein concentrations per mg aphid.
Context: Assesses the nutritional quality of aphids in terms of protein, a key macronutrient for predators.
Method.2.5a_cage_predation
Purpose: Results from in-cage predation assays under semi-natural conditions.
Measurement: Aphid initial and final counts under predator-present and predator-absent treatments; predator numbers introduced per cage.
Context: Tests combined effects of plant defense and natural predation on aphid suppression.
Method.2.5b_petridish_predation
Purpose: Results from Petri-dish no-choice predator feeding assays.
Measurement: Number of aphids consumed and biomass consumed by individual lady beetles over 4 hours.
Context: Measures compensatory feeding behavior of predators when aphid prey varies in quality due to plant treatment.
metadata
Purpose: Explains variable names and units for all other sheets.
Context: Ensures clarity and reuse of the dataset.
Excel Sheets:
Method.2.3_aphid_reproduction
- Description: Records daily aphid reproduction and adult survival under control and SA-treated plants.
- Variables:
Plant— Unique plant IDTreatment— SA-treated or ControlTrial— Experimental blocktotal_nymphs— Cumulative nymph productiontotal_adults— Total surviving adultsnymph_per_adult— Nymph production per surviving adult
Method.2.3_lifespan
- Description: Aphid survival time across treatments.
- Variables:
time— Time in daysp_id— Aphid individual IDreplicate— Replicate IDtreatment— SA-treated or Controltrial— Experimental blockcensor— Censoring status (0 = dead, 1 = alive)status— Survival status
Method.2.4_biomass
- Description: Individual aphid body mass measurements.
- Variables:
plant— Plant IDtreatment— SA-treated or Controlweight_mg— Individual mass in milligramstrial— Trial replicateapihd— Aphid sample ID
Method.2.4_glucose_analysis
- Description: Aphid glucose concentration normalized by body weight.
- Variables:
sample— Sample IDtreatment— SA-treated or Controlglucose_concentration_mean— Mean glucose reading (µg/mg)weight_mg— Sample weightglucose_per_mg_aphid— Glucose normalized per mg aphid
Method.2.4_triglyceride_analysis
- Description: Aphid triglyceride (lipid) concentration per mg body weight.
- Variables:
sample— Sample IDtreatment— SA-treated or Controltriglyceride_concentration_mean— Mean triglyceride reading (µg/mg)weight_mg— Sample weighttriglyceride_mg_aphid— Triglyceride normalized per mg aphid
Method.2.4_protein_analysis
- Description: Aphid protein concentration per mg body weight.
- Variables:
sample— Sample IDtreatment— SA-treated or Controlweight_mg— Sample weightprotein_concentration_fr_gluc— Raw protein concentrationprotein_by_weight_mean— Protein per mg aphid
Method.2.5a_cage_predation
- Description: In-cage aphid population suppression under predator-present and predator-absent conditions.
- Variables:
cage_id— Unique cage IDtrial— Experiment blockdefense_code— Numerical defense treatment codedefense— SA-treated or Controlpredator— Predator present (Yes/No)block— Block numbertotal_i— Initial aphid countpred_added_n— Number of predators addedtotal_f— Final aphid count
Method.2.5b_petridish_predation
- Description: Petri-dish predator feeding assays measuring aphid mortality and biomass consumption.
- Variables:
trial— Trial replicatedefense— SA-treated or Controltime_min— Time (minutes)petridish_id— Unique Petri dish IDinoculation_n— Initial number of aphidsweight_mg— Initial biomassn_consumed— Number of aphids consumedweight_mg_consumed— Biomass consumed
metadata
- Description: Descriptions and explanations for all column headers used across sheets.
File Formats
- Excel Workbook (.xlsx) for tabular data
- CSV format can be generated for preservation and compatibility if needed.
Variable Notes
- Biomass measures are reported in milligrams (mg).
- Nutrient concentrations are normalized by body mass wherever indicated.
Software Used
- R version 4.2.2
- Packages:
glmmTMB,emmeans,DHARMa,car,survival
Licensing
All data are made available under the Creative Commons CC0 Public Domain Dedication. No rights reserved.