Dataset associated with "Artefactual depiction of predator–prey trophic linkages in global soils"

This database contains results from an exploratory literature search (carried out over May-July 2020) to detect the trophic linkages that departed from an initial set of 36 common soil-dwelling invertebrate taxa (i.e., in the capacity of either predator or prey items). It consists of a non-exhaustive list of macro-, meso- and micro-fauna which did not necessarily include all common soil fauna (e.g., Amphipoda). For each literature record, we logged the resource and consumer organisms for each trophic linkage. For generalist (i.e., polyphagous) predators that foraged within/on soil substrates, we logged all trophic linkages that were outlined in each literature record (i.e., involving other organisms beyond the initial set of 36 taxa). Taxa were identified either at the taxonomic hierarchy of phylum, sub-class or order and comprised a diverse set of common, globally-distributed soil-foraging biota.Soil invertebrates contribute to multiple ecosystem services, including pest control, nutrient cycling, and soil structural regulation, yet trophic interactions that determine their diversity and activity in soils remain critically understudied. Here, we systematically review literature (1966–2020) on feeding habits of soil arthropods and macrofauna and summarize empirically studied predator–prey linkages across ecosystem types, geographies and taxa. Out of 522 unique predators and 372 prey organisms (constituting 1947 predator–prey linkages), the vast majority (> 75%) are only covered in a single study. We report a mean of just 3.0 ± 4.7 documented linkages per organism, with pronounced taxonomic biases. In general, model organisms and crop pests (generally Insecta) are well-studied, while important soil-dwelling predators, fungivores and detritivores (e.g., Collembola, Chilopoda and Malacostraca) remain largely ignored. We argue that broader food-web based research approaches, considering multiple linkages per organism and targeting neglected taxa, are needed to inform science-driven management of soil communities and associated ecosystem services

Phytoplasma Infection of a Tropical Root Crop Triggers Bottom-Up Cascades by Favoring Generalist Over Specialist Herbivores

Global interest on plant-microbe-insect interactions is rapidly growing, revealing the multiple ways in which microorganisms mediate plant-herbivore interactions. Phytopathogens regularly alter whole repertoires of plant phenotypic traits, and bring about shifts in key chemical or morphological characteristics of plant hosts. Pathogens can also cause cascading effects on higher trophic levels, and eventually shape entire plant-associated arthropod communities. We tested the hypothesis that a Candidatus Phytoplasma causing cassava witches’ broom (CWB) on cassava (Manihot esculenta Grantz) is altering species composition of invasive herbivores and their associated parasitic hymenopterans. We conducted observational studies in cassava fields in eastern Cambodia to assess the effect of CWB infection on abundance of specialist and generalist mealybugs (Homoptera: Pseudococcidae), and associated primary and hyper-parasitoid species. CWB infection positively affects overall mealybug abundance and species richness at a plant- and field-level, and disproportionately favors a generalist mealybug over a specialist feeder. CWB phytoplasma infection led to increased parasitoid richness and diversity, with richness of ‘comparative’ specialist taxa being the most significantly affected. Parasitism rate did not differ among infected and uninfected plants, and mealybug host suppression was not impacted. CWB phytoplasma modifies host plant quality for sap-feeding homopterans, differentially affects success rates of two invasive species, and generates niche opportunities for higher trophic orders. By doing so, a Candidatus phytoplasma affects broader food web structure and functioning, and assumes the role of an ecosystem engineer. Our work unveils key facets of phytoplasma ecology, and sheds light upon complex multi-trophic interactions mediated by an emerging phytopathogen. These findings have further implications for invasion ecology and management

Neonicotinoids in global agriculture:Evidence for a new pesticide treadmill?

Overreliance on synthetic insecticides in global agriculture is the outcome of a “pesticide treadmill,” in which insecticide-induced pest resistance development and the depletion of beneficial insect populations aggravate farmers’ pesticide dependencies. Examples of the pesticide treadmill have been witnessed repeatedly over the past seven decades, prompting the question whether the rapid uptake and usage patterns of neonicotinoid insecticides and their associated environmental impact are in accordance with this recurrent phenomenon. We hypothesize a conceptual framework in which treadmills are enforced by enabling or disabling drivers within four domains: pest management decisions at the farm level, characteristics of farming landscapes, science and technology, and societal demands. These drivers then tend to create a self-enforcing pesticide “lock-in.” We then analyze several post-1950s historical case studies with reference to this framework, e.g., those involving sprays of the highly hazardous DDT and methyl-parathion, in which the pesticide treadmill was initiated, sustained, and broken, and compare this with current patterns in neonicotinoid use. Historical case studies further illustrate how treadmills occur in three phases in which (i) a limited number of insecticides are routinely used, (ii) resistance development of pests results in the increased crop injury, prompting increased frequency of applications with a wider range of products, (iii) breaking out of the pesticide “lock-in” by policy change and adoption of alternative technologies that lowered chemical inputs and improved agro-ecosystem functioning. The analysis shows similarities as well as differences between neonicotinoid usage patterns and historic pesticide treadmills, and provides guidance on how to effectively avoid or dismantle pesticide treadmills in global agriculture

On-farm diversity offsets environmental pressures in tropical agroecosystems: A synthetic review for cassava-based systems

Peer Revie

Ecosystem services in cassava intercropping: a global synthetic review

Intensification and extensification of agriculture are eroding the integrity of tropical ecosystems. As global land comes under increasing anthropogenic management, considering the impacts of management practices on ecosystem services (ES) is essential. Cassava (Manihot esculenta Crantz) cultivation has expanded dramatically in the tropics, currently representing over 25 million hectares managed by millions of smallholders (Fig. 1). Diversification is often cited as a strategy for augmenting the functioning of ES in agricultural landscapes (Brooker et al., 2015; Kremen & Miles, 2012). Despite this, attempts to comprehensively evaluate diversification practices in cassava from an ES perspective remain rare. We conducted a systematic literature review of intercropping in cassava cultivation systems, and employed the concept of ES bundles to evaluate the impacts of diversification on a key set of ES

Exploración de la variabilidad genética del maracuyá (passiflora edulis f. flavicarpa degener) como base para un programa de fitomejoramiento en colombia

El maracuyá es uno de los principales frutales del Neotrópico y en Colombia existen cerca de 6000 ha cultivadas con esta fruta, con una producción de 90,000 t/año. No obstante este potencial, los cultivos presentan graves problemas fitosanitarios y degeneración genética, lo que se manifiesta por una reducción de la vida útil de la plantación. El objetivo de esta investigación fue evaluar el grado de variabilidad genética del maracuyá cultivado en Colombia como base para un programa de fitomejoramiento. Las recolecciones se realizaron en los departamentos de Antioquia, Caldas, Cauca, Huila, Tolima y Valle del Cauca mediante una selección masal participativa con los productores. En cada cultivo, se seleccionaron diez frutos al azar (calidad extra) de las plantas más sobresalientes por productividad y sanidad, en las cuales se registró la incidencia de insectos plaga y enfermedades. Los frutos fueron caracterizados con 11 variables fisicoquímicas y analizados mediante la descomposición de la varianza (univariado) y el análisis de clasificación (neighbour joining). Los resultados mostraron que los trips (Neohydatothrips spp.) y la virosis (SMV) son los problemas fitosanitarios que más afectan el cultivo en los sitios del estudio. El análisis univariado del fruto mostró un porcentaje de variabilidad promedio total de 14.31% (CV), destacándose los pesos de la cáscara (20.53%) y de la semilla (20.47%). Tomando en cuenta los parámetros de calidad (ºBrix y %pulpa + semilla) se identificaron ocho accesiones élite provenientes de Caldas, Valle del Cauca y Antioquia. El análisis de clasificación mostró una alta variabilidad, con poca estructuración por origen geográfico. Estos resultados permitirán iniciar un proceso de mejoramiento genético a partir de genotipos superiores de las accesiones élite identificadas.Yellow passion fruit is one of the main fruit of the Neotropic and in Colombia there are about 6.000 ha with a 90.000 t/year production. Despite this potential, crops are affected by serious phytosanitary problems, genetic degeneration and lack of breeding in those species that have allowed a reduction of their crop cycle. The objective of this research was to determine the genetic variability degree yellow passion fruit cultivated in Colombia as the basis for a breeding program. The collections were made in the departments of Antioquia, Caldas, Cauca, Huila, Tolima and Valle del Cauca through farmer´s participatory mass selection. Ten fruits per crop were selected randomly (extra quality) of the most outstanding material (productivity and health) and the incidence of insect pests and diseases recorded. Fruits were characterized with 11 physicochemical variables and analyzed using the variance decomposition (univariate) and classification analysis (Neighbour joining). Results identified that Trips (Neohydatothrips sp.) and Virosis (SMV) are the plague and disease with greater affectation in the crops visited. The results of the fruit analysis showed a total average variability percentage (CV) of 14.31%, highlighting the weight of the fruit peel (20.53%) and the average seed weight (20.47%). Regarding quality parameters (°Brix and % pulp+seeds) eight élite accessions from Caldas, Valle de Cauca and Antioquia were identified. The classification analysis showed high variability with little structuring by geographic origin. These results will begin a breeding process from superior genotypes from the identified élite accessions