Soil Acarology (Mites)
Day – 3
Felicity Crotty
Mite Phylogeny
Day – 3
Felicity Crotty
>30 taxa
5000
1500 25 0
00
6500
730
160 600
60 0
00
1600
8800
5000
2500
10 0
00
9260
9539 208 3
00
70
3627
162 773
56
52
%
75
%
47
%
50
%
54
%
99
%
NE
NE
NE
NE
NE
NE
NE
1
10
100
1000
10 000
100 000
1 000 000
10 000 000
Estimated, undescribed species
Known species
NE
83
%
41
%
75
%
NE
97
%
99
% 72
%
Species number
Body size Source: Decaëns et al. (2006)
But mostly unknown...
What is a Mite?!?
Tiny but diverse arachnids related to spiders, are some of the most abundant and diverse groups of invertebrate fauna. Found in all environments worldwide, from the deserts to the polar regions and everything in between . The are predators, fungivores, detritivores and even herbivores. Thus occupying many different niches and speciating to adapt to the ecosystem they are inhabiting
Parasitiformes
Mesostigmata
• Cosmopolitan
• Most free living predators
• Suborders:
- Sejida
- Trigynaspida
- Monogynaspida
Holothyrida
• In leaf litter, mosses and under stones in moist forests
• rare
• Families:
- Holothyridae
- Allothyridae
- Neothyridae
Ixodidae
• Obligate blood sucking parasites
• Common
• Families:
- Ixodidae (Hard)
- Argasidae (Soft)
- Nuttalliellidae
Opilioacaridae
• Look superficially like harvestmen
• Found in caves, also under rocks and litter
• Moderately rare
• 6 genera; 20 species
Parasitiformes
Mesostigmata
• Cosmopolitan
• Most free living predators
• Suborders:
- Sejida
- Trigynaspida
- Monogynaspida
Holothyrida
• In leaf litter, mosses and under stones in moist forests
• rare
• Families:
- Holothyridae
- Allothyridae
- Neothyridae
Ixodidae
• Obligate blood sucking parasites
• Common
• Families:
- Ixodidae (Hard)
- Argasidae (Soft)
- Nuttalliellidae
Opilioacaridae
• Look superficially like harvestmen
• Found in caves, also under rocks and litter
• Moderately rare
• 6 genera; 20 species
Acariformes
Sarcoptiformes (Oribatida)
• Mostly Oribatids (Endeostigmata also a suborder in this group and Astigmata a cohort within Oribatida)
• Oribatids four supercohorts considered “lower” oribatids – MACROPYLINE one supercohort considered “higher” – BRACHYPYLINE
• Extremely common
Trombidiformes (Prostigmata)
• Mostly Prostigmata (Sphaerolichida also a suborder in this group)
• Prostigmata with five supercohorts (variable family number within)
• Extremely common
• Mixture of predators and herbivores/fungivores
• Many have a phoretic immature stage “chiggers”
UK MESOSTIGMATA = 501 SPECIES
UK ORIBATIDS = 311 SPECIES ASTIGMATINA = 278 SPECIES
UK PROSTIGMATA = 910 SPECIES
Mite Ecology
Day – 3
Felicity Crotty
Active layer
• Most of the action occurs in the first 2cm of soil
• All invertebrates living in top 10 cm of soil
• (Some worms and mammals further down than this)
Not just earthworms affecting soil structure!
Importance of SOIL BIOLOGY
Earthworm weight can be greater per hectare than livestock grazing it! Up to 2 tonnes per ha
On average we’ve found over 1 tonne per ha (1082 kg)
Grassland soils: “Mesofauna” (springtails & mites) found up around 60,000 m2.
We have apx 23,000 springtails and 41,000 mites per m2. = 64,000 per m2
Almost nothing known of the biology and basic needs of most
native species
van Eekeren, Murray & Smeding (2007)
Cyclic interactions
More food for soil biota Improved habitat for soil biota
Improved soil structure Improved nutrient cycling Improved water regulation
Greater plant yield (more litter produced) More efficient moisture and nutrient uptake Improved rooting
Blue = Bacterial Green = Fungal Red = Root
Adapted from De Ruiter et al. (1993) J. Appl. Ecol. 30, 95-106
Roots
Phytophagous nematodes
Rhizophagous aphids
Detritus
Fungi
Collembola
Cryptostig. mites
Non-cryptostig. mites
Fungivorous nematodes
Earthworms
Enchytraeids
Bacteriophagous nematodes
Flagellates
Bacteriophagous mites
Amoebae
Predaceous nematodes
Nematode feeding mites
Predaceous collembola
Predaceous mites
Winter Wheat fields: Netherlands
Bacteria
Trophic patterns in Acari
Feeding strategies
Saprophagy (phyllophagy) – using parenchymous tissue of dead leaves
Saprophagy (xylophagy) – using woody structural tissue / dead plant parts e.g. Mixonomata species
R. Norton R. Norton
Saprophagy (Phyllo / Xylo)
Energy Flow
DIRECT: Assimilation of energy from plant materials (BUT low quality food – high C:N; produce large faecal pellets – little of C is used) INDIRECT: Production of faecal pellets with greater surface area – “material going through digestive tract of total mite population in 1 year, apx equal to 50% of annual litter fall!” Berthet 1964 DIRECT: Assimilation of nutrients from plant materials; Concentration of nutrients (and heavy metals) INDIRECT: Shredding increases nutrient leaching
Nutrient Cycling
Feeding strategies
Mycophagy – feeding on fungal hyphae or spores (usually growing on decaying plant material)
Other strategies include:
- Necrophagy
- Coprophagy
- Bacteriophagy
- Nematophagy
- Protistivory
- Herbivory (root / living tissue)
- Algivory
- Omnivory
- Predation
Mycophagy / Bacteriophagy
Energy Flow
DIRECT: Assimilation of energy from microflora
INDIRECT: Stimulation / suppression of microfloral activities. Dispersal of hyphae/spores. Selective grazing.
DIRECT: Assimilation of nutrients from plant materials; Concentration of nutrients (and heavy metals)
INDIRECT: Stimulation or suppression of microfloral activities
Nutrient Cycling
Functional groups of mites (cf. Moore et al. 1988)
Functional Group Description Taxa
General predators Attack anything smaller Mesostigmata
Arthropod predators Attack only Arthropods Many Prostigmata
Nematode Predators Only nematodes Mesostigmata Some Oribatida
Fluid feeding fungivore Pierce and suck fluids of fungi, protists
Prostigmata
Engulfing fungivores Ingest bits of fungi, hyphae, algae, spores
Oribatida Astigmata
Root fluid feeders (Herbivores)
Pierce roots and suck fluids Some Prostigmata
Detritivores Ingest dead plant material Oribatida Astigmata
Coprophagous Ingest faecal / exoskeleton material
Oribatida Astigmata
Aboveground communities are affected by both direct and indirect consequences of soil food web. - Indirect (R) detritus food web stimulate nutrient turnover improving plant performance. - Direct (L) soil biota feed on roots and form antagonistic / mutualistic relationships Wardle et al., Science 2004
Microhabitats
• Burrowers
• Soil dwellers
• Lichen associates
• Saxicoles (rock dwellers)
• Arboreal – “island soil colonies”
• Marine littoral
• Fresh water
• Insect Associates
Biology
• The majority of the Mesostigmata and Prostigmata are r-strategists with fast reproductive cycles, short lifespans and quick recovery times to perturbations
• Majority of the Oribatids are k-strategists with slow reproductive cycles, long lifespans and are slow to recover to perturbations – may therefore be a good indication group
Mite Glossary
http://itp.lucidcentral.org/id/mites/invasive_mite/Invasive_Mite_Identification/key/0_Glossary/
Mite_Glossary.htm
JARGON
Body Regions
• -soma = body
• Pro- = front
• Opistho- = back
• Podo- = foot
• Gnatho- = jaw/mouth/head
• Idio- = distinct / unique
Different order = different words OR even different key
• Prosoma = front body
- carapace?
- prodorsal
- pronotal ≠ notum = back
- podonotal
• Opisthosoma = back body
- Opisthonotal
- Opisthogaster (gaster = stomach)
Mouth parts/head
Legs I & II
Legs III & IV
Abdomen region
Gnathosoma (sometimes referred to as capitulum)
Propodosoma (dorsal surface = prodorsum)
Metapodosoma
Opisthosoma (Opisthonotal if dorsal)
Podosoma
Idiosoma (body) Gaster if ventral or notum if dorsal
Prosoma (= cephalothorax) Aspidosoma is anterior dorsal region
Proterosoma (Anterior of sejugal furrow)
Hysterosoma (Rear of sejugal furrow) Dorsally called notogaster
Mite arbitrary body divisions (JARGON)
JARGON… It’s getting “trichy”
- CHAETOTAXY (setal position / hairs)
• Holotrichy – complete complement of setae thought to be present in ancestral group
- Unideficient – lost one setae (f1)
• Neotrichy – setae not in ancestral condition (new hairs)
• Hypertrichy – extra setae
Acknowledgments
Soil Mite Experts
Cal Welbourne
Valerie Behan-Pelletier
Roy Norton
David Walter