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Earth's Systems / Biological processes / Terrestrial ecosystem functioning / Living soil system / Soil fauna / Nematode feeding guilds and control of root feeders

Nematode feeding guilds and control of root feeders

Soil nematodes split into bacterial feeders, fungal feeders, plant parasites, omnivores and predators. This subprocess shows how each guild affects nitrogen release or root damage, how natural enemies hold plant parasites in check, and how nematode community indices read disturbance.

Boundary: where this process starts

Starts with: Soil nematodes sort into feeding guilds: bacterivores, fungivores, plant parasites, omnivores and predators

Boundary: where it ends

Ends after: Bacterivorous nematodes excrete ammonium because bacteria are N-rich prey; nematodes account for roughly 5-20% of net N mineralization (wide range); Plant-parasitic nematodes (root-knot Meloidogyne, cyst Heterodera and Globodera) feed on roots; root-knot nematodes induce giant cells that act as nutrient sinks

PARTICIPANTSRESOURCESNematodesPlant rootsSoil microbesBacterial-feedingnematodesSoil bacteriaOtherparticipantsBacterialbiomassRoot tissueNitrogenCarbonFungal biomassImpact +3 of 5. Click for details and evidence.Impact +2 of 5. Click for details and evidence.Guilds carry life-history trImpact +3 of 5. Click for details and evidence.Bacterial feedingImpact -3 of 5. Click for details and evidence.Plant feedingImpact +2 of 5. Click for details and evidence.Predation by upper trophic lImpact +3 of 5. Click for details and evidence.Dense hosts feed spore-attacImpact -3 of 5. Click for details and evidence.↻ balances · moderate · 0.3 Antagonists suppImpact +2 of 5. Click for details and evidence.Bacterivores feed predatorsImpact -2 of 5. Click for details and evidence.↻ balances · weak · 0.2 Predation holds bactImpact 03 of 5. Click for details and evidence.Index responds to disturbancImpact +3 of 5. Click for details and evidence.Ammonium releasedImpact -3 of 5. Click for details and evidence.Root damageImpact 02 of 5. Click for details and evidence.Community diagnostic of soilSoil nematodes sort into feeding guilds: bacterivores, fungivores, plant parasites, omnivores and predators: uses Bacterial biomassSoil nematodes sort into feeding guilds: bacterivores, fungivores, plant parasites, omnivores and predators: uses Root tissueSoil nematodes sort into feeding guilds: bacterivores, fungivores, plant parasites, omnivores and predators: uses Fungal biomassColonizer-persister scale: c-p 1 enrichment opportunists reproduce within days; c-p 5 predators and omnivores have long generations and are disturbance sensitive: uses CarbonBacterivorous nematodes excrete ammonium because bacteria are N-rich prey; nematodes account for roughly 5-20% of net N mineralization (wide range): uses up Bacterial biomassuses upBacterivorous nematodes excrete ammonium because bacteria are N-rich prey; nematodes account for roughly 5-20% of net N mineralization (wide range): makes NitrogenmakesPlant-parasitic nematodes (root-knot Meloidogyne, cyst Heterodera and Globodera) feed on roots; root-knot nematodes induce giant cells that act as nutrient sinks: uses up Root tissueuses upPlant-parasitic nematodes (root-knot Meloidogyne, cyst Heterodera and Globodera) feed on roots; root-knot nematodes induce giant cells that act as nutrient sinks: uses NitrogenPlant-parasitic nematodes (root-knot Meloidogyne, cyst Heterodera and Globodera) feed on roots; root-knot nematodes induce giant cells that act as nutrient sinks: uses CarbonAntagonists hold root feeders in check: nematode-trapping fungi (Arthrobotrys) and Pasteuria bacterial spores that attach to the cuticle: uses Root tissuePredatory and omnivorous nematodes (Mononchida, Dorylaimida) eat other nematodes, adding a trophic level that slows prey growth: uses Bacterial biomassDisturbance reshapes the nematode community: tillage and fertilizer favour c-p 1 enrichment opportunists, while undisturbed soils keep c-p 4-5 taxa: uses Nitrogeneaten by bacterivoresBacterial biomass: eaten by bacterivoresfed upon by plantparasitesRoot tissue: fed upon by plant parasiteseaten by fungivoresFungal biomass: eaten by fungivorescycled as nematodebiomassCarbon: cycled as nematode biomassgrazed by bacterivorousnematodesBacterial biomass: grazed by bacterivorous nematodesmineralised by nematodeexcretionNitrogen: mineralised by nematode excretionfed upon by nematodesRoot tissue: fed upon by nematodesdrawn into giant-cellsinksNitrogen: drawn into giant-cell sinksincorporated intonematode tissueCarbon: incorporated into nematode tissueshielded fromroot-feeding nematodesRoot tissue: shielded from root-feeding nematodesindirectly reduced bypredatorsBacterial biomass: indirectly reduced by predatorsfertilizer boostsenrichment opportunistsNitrogen: fertilizer boosts enrichment opportunistsStart: Nematode feedingguilds and control ofroot feedersSTARTStart: Nematode feeding guilds and control of root feedersEnd: Nematode feedingguilds and control ofroot feedersENDEnd: Nematode feeding guilds and control of root feedersSoil nematodes sortinto feeding guilds:bacterivore…📄1Soil nematodes sort into feeding guilds: bacterivores, fungivores, plant parasites, omnivores and predatorsColonizer-persisterscale: c-p 1 enrichmentopportunists reprodu…📄1Colonizer-persister scale: c-p 1 enrichment opportunists reproduce within days; c-p 5 predators and omnivores have long generations and are disturbance sensitiveBacterivorous nematodesexcrete ammoniumbecause bacteria a…📄1Bacterivorous nematodes excrete ammonium because bacteria are N-rich prey; nematodes account for roughly 5-20% of net N mineralization (wide range)Plant-parasiticnematodes (root-knotMeloidogyne, cy…📄1Plant-parasitic nematodes (root-knot Meloidogyne, cyst Heterodera and Globodera) feed on roots; root-knot nematodes induce giant cells that act as nutrient sinksAntagonists hold rootfeeders in check:nematode-trapping fun…📄1Antagonists hold root feeders in check: nematode-trapping fungi (Arthrobotrys) and Pasteuria bacterial spores that attach to the cuticlePredatory andomnivorous nematodes(Mononchid…📄1Predatory and omnivorous nematodes (Mononchida, Dorylaimida) eat other nematodes, adding a trophic level that slows prey growthDisturbance reshapesthe nematode community:tillage and fertiliz…📄1Disturbance reshapes the nematode community: tillage and fertilizer favour c-p 1 enrichment opportunists, while undisturbed soils keep c-p 4-5 taxa
Line thickness = size of impact (1 to 5)% on a line = chance a fork takes that branch📄 = pieces of evidence on a stepNegative effectLoops backHypothesisResource used up (arrow into the step)Resource used, not used upResource made or released (arrow out of the step)
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Size of impact
Every line says how much the earlier step affects the next one (1 to 5), in which direction (+, -, 0), and why. Thicker lines mean bigger impact.
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Every step, with its evidence

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Soil nematodes sort into feeding guilds: bacterivores, fungivores, plant parasites, omnivores and predators
NematodesBacterial biomassFungal biomassRoot tissue
Evidence (1) · added by Ember
  • Yeates et al. 1993, Journal of Nematology 25:315: Mouthpart structure assigns each nematode family to a feeding guild. (confidence 0.85)
Colonizer-persister scale: c-p 1 enrichment opportunists reproduce within days; c-p 5 predators and omnivores have long generations and are disturbance sensitive
NematodesCarbon
Evidence (1) · added by Ember
  • Bongers 1990, Oecologia 83:14, The maturity index: an ecological measure of environmental disturbance based on nematode species composition: The maturity index weights nematode taxa from c-p 1 (opportunists) to c-p 5 (persisters); it falls under disturbance. (confidence 0.85)
Bacterivorous nematodes excrete ammonium because bacteria are N-rich prey; nematodes account for roughly 5-20% of net N mineralization (wide range)
Bacterial-feeding nematodesSoil bacteriaBacterial biomassAmmoniumNitrogen
Evidence (1) · added by Ember
  • Ingham, Trofymow, Ingham & Coleman 1985, Ecological Monographs 55:119, Interactions of bacteria, fungi, and their nematode grazers: effects on nutrient cycling and plant growth: Microcosms with nematode grazers mineralized more N than microbes alone; the nematode share was modest, in the single-digit to roughly 20% range. (confidence 0.5)
Plant-parasitic nematodes (root-knot Meloidogyne, cyst Heterodera and Globodera) feed on roots; root-knot nematodes induce giant cells that act as nutrient sinks
Plant-parasitic nematodesPlant rootsRoot tissueCarbonNitrogen
Evidence (1) · added by Ember
  • Jones et al. 2013, Molecular Plant Pathology 14:946, Top 10 plant-parasitic nematodes in molecular plant pathology: Root-knot nematodes top the ranking; they reprogram root cells into giant cells that feed the parasite. (confidence 0.85)
Antagonists hold root feeders in check: nematode-trapping fungi (Arthrobotrys) and Pasteuria bacterial spores that attach to the cuticle
Nematophagous fungiPasteuria penetransRoot tissue
Evidence (1) · added by Ember
  • Chen & Dickson 1998, Journal of Nematology 30:313, Review of Pasteuria penetrans: biology, ecology, and biological control potential: Pasteuria endospores attach to root-knot nematode cuticle and sterilize or kill females; suppression grows with spore density. (confidence 0.7)
Predatory and omnivorous nematodes (Mononchida, Dorylaimida) eat other nematodes, adding a trophic level that slows prey growth
Predatory nematodesOmnivorous nematodesBacterial biomass
Evidence (1) · added by Ember
  • Wardle 2002, Communities and Ecosystems: Linking the Aboveground and Belowground Components, Princeton University Press: Higher nematode trophic levels regulate lower ones in soil food webs. (confidence 0.6)
Disturbance reshapes the nematode community: tillage and fertilizer favour c-p 1 enrichment opportunists, while undisturbed soils keep c-p 4-5 taxa
NematodesTillageNitrogen
Evidence (1) · added by Ember
  • Ferris, Bongers & de Goede 2001, Applied Soil Ecology 18:13, A framework for soil food web diagnostics: extension of the nematode faunal analysis concept: Enrichment and structure indices separate nutrient-enriched and disturbed soils from structured, undisturbed food webs. (confidence 0.8)