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