DOI: 10.5061/dryad.r7sqv9spj
title: Data from: Generalist predators function as pest specialists: Examining diet composition of spiders and ladybeetles across rice crop stages

description: Biocontrol, the use of natural enemies to manage pests, has a long history
 in agriculture.  It has gained renewed interest because of its
 importance in sustainable agriculture.  To solve a long-standing
 puzzle in biocontrol—how well the ubiquitous generalist arthropod
 predators (GAPs) function as biocontrol agents—this study aimed to 1)
 quantify the diet composition of GAPs (spiders and ladybeetles) at
 different crop stages using stable isotope analysis, 2) examine the
 consistency of GAPs in pest consumption over years, and 3) investigate how
 abiotic and biotic factors (farm type, crop stage, surrounding vegetation,
 and relative prey abundance) affect pest consumption by GAPs.
 Specifically, we sampled arthropod prey and GAPs in seven pairs of
 sub-tropical organic and conventional rice farms over crop stages
 (seedling, tillering, flowering, and ripening) in three consecutive
 years.  Among our sweep-net samples, 352 arthropod predator and
 828 prey isotope samples were analyzed to infer predator-prey
 interactions. Our results show the following:  a) The proportion
 of rice pests in GAPs’ diets in both organic and conventional rice farms
 increased over the crop season, from 21-47% at the tillering stage to
 80-97% at the ripening stage, across the three study years.  The
 high percentage of pest consumption at late crop stages (flowering and
 ripening) suggests that GAPs can function as specialists in pest
 management during the critical period of crop production. 
 Regarding individual predator groups, spiders and lady beetles exhibited
 distinct dietary patterns over crop stages.  b) The high pest
 consumption by GAPs at late crop stages was similar across years despite
 variable climatic conditions and prey availability, suggesting a
 consistency in GAP feeding habits and biocontrol value.  c) The
 proportion of rice pests in GAPs’ diets varied with farm type and crop
 stage (e.g., higher in conventional farms and during flowering/ripening
 stages). Synthesis and applications: By quantifying the diet composition
 of GAPs over crop stages, farm types, and years, this study reveals that
 generalist predators have the potential to produce a stable, predictable
 top-down effect on pests in rice agroecosystems.  Therefore,
 promoting the field densities of ubiquitous generalist predators will
 likely enhance pest management and support sustainable agriculture.
description: # Generalist predators function as pest specialists: Examining diet
 composition of spiders and ladybeetles across rice crop stages Dataset
 DOI: [10.5061/dryad.r7sqv9spj](10.5061/dryad.r7sqv9spj) ## Description of
 the data and file structure The data report the stable isotope signatures
 of arthropods collected from rice fields. ### Files and variables ####
 File: SID\_2017\_Dryad.csv **Description:** Arthropods collected in 2017
 ##### Variables * No.: Replicate * ID: Replicate ID * Date: Collection
 date * Species: Species name * Amount_mg: Sample weight (mg) * Conc_N_%:
 Nitrogen content * d_15N: The ratio of nitrogen isotopes * Conc_C_%:
 Carbon content * d_13C: The ratio of carbon isotopes * Farm_type: Organic
 or conventional farms * Stage: Rice crop stage * Trophic: Trophic level
 #### File: SID\_2018\_Dryad.csv **Description:** Arthropods collected in
 2018 ##### Variables * Sample.ID: Replicate * Family: Species family *
 d13C: The ratio of carbon isotopes * C.amount_ug: Carbon amount (ug) *
 d15N: The ratio of nitrogen isotopes * N.amount_ug: Nitrogen amount (ug) *
 Total.amount_mg: Sample weight (mg) * Farmtype: Organic or conventional
 farms * Stage: Rice crop stage * Farm.ID: Farm replicate ID * Date:
 Collection date #### File: SID\_2019\_Dryad.csv
 **Description:** Arthropods collected in 2019 ##### Variables * Sample.ID:
 Replicate * Family: Species family * d13C: The ratio of carbon isotopes *
 C.amount_ug: Carbon amount (ug) * d15N: The ratio of nitrogen isotopes *
 N.amount_ug: Nitrogen amount (ug) * Total.amount_mg: Sample weight (mg) *
 Farmtype: Organic or conventional farms * Stage: Rice crop stage *
 Farm.ID: Farm replicate ID * Date: Collection date * Year: Collection year
 ## Code/software Excel or R used for the analysis. ## Access information
 Other publicly accessible locations of the data: * NA Data was derived
 from the following sources: * NA