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  1. The ratio of parthenogenetic oribatid mite species increases with increasing intensity of land use.
  2. The ratio of parthenogenetic oribatid mite species increases with increasing amount of available nutrition.
  3. Phytophagous diet evolved convergently multiple times in the evolutionary younger groups of oribatid mites.

Soil samples were taken in forests along a land use gradient. The thickness of the litter layer differs between forests and will be used as a measurement for resources. Sex and species identity of sampled oribatid mites were determined. Subsequently the sex ratios were correlated with the amount of resources and oribatid mite density. Stable isotope ratios of 15N and 13C of single species were measured to classify their trophic position. In cooperation with the projects ‘LitterLinks‘ and ‘ModelWeb‘, the data will be merged for characterizing and modeling a soil food web. For investigations about the influence of resources on oribatid mite communities and their mode of reproduction on bark, fertilization with carbon and nitrogen will be applied. The species communities were sampled after different time spans of continuous fertilization.Erdmann et al. (2007) highlighted the difference of species identities on bark and in soil habitats. Oribatid mites on bark are associated with the growth cover and therefore with the food resource. This implies the hypothesis that oribatid mites in soil and on bark live in the respective habitat and use their specific food. To test this hypothesis, feeding experiments will be conducted in the laboratory. The Project ‘SoilAlgae‘ provides algal cell cultures. Typical oribatid mite species from bark and soil will be fed with typical algae each from soil and above ground habitats. We hypothesize that mites feed specific and prefer the algal species from their corresponding habitat.To test food preferences in the field, oribatid mites were collected (in cooperation with Steffen Boch, project Botanik) on bark and lichens. We want to proof if abundances of oribatid mites correlate with secondary compounds produced by lichens which potentially act as repellents.It is assumed that the interaction between resources and oribatid mites is an important factor which drives evolution. Especially the evolution of arboricolous and lichenivorous oribatid mites could be pushed by ecological factors.We constructed a phylogenetic tree for soil living and arboricolous mite species. The colonization of bark habitat occurred multiple times and convergently in the evolutionary younger taxa. These taxa consist mainly of strong sclerotized species which reproduce sexually. The data support the thesis that ecological factors were most important for the multiple colonization of bark by oribatid mites (Maraun et al. 2009).


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Bluhm C. (2016): Oribatid mite community structure and trophic ecology along a forest land-use gradient: effect of dead wood, time and root-trenching. Dissertation, University Göttingen
More information:  ediss.uni-goettingen.de
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Oribatidengemeinschaften auf der Borke von Totholz werden vom Stammtyp, dem umliegenden Wald und der Region beeinflusst
Bluhm C., Scheu S., Maraun M. (2015): Oribatid mite communities on the bark of dead wood vary with log type, surrounding forest and regional factors. Applied Soil Ecology 89, 102–112. doi: 10.1016/j.apsoil.2015.01.013
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Zeitliche Fluktuationen von Hornmilben-Populationen deuten darauf hin, dass dichte-unabhängige Regulationen von Populationen parthenogenetische Reproduktion fördern
Bluhm C., Scheu S., Maraun M. (2016): Temporal fluctuations in oribatid mites indicate that density-independent factors favour parthenogenetic reproduction. Experimental and Applied Acarology 68 (4), 387-407. doi: 10.1007/s10493-015-0001-6
More information:  doi.org
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Erdmann G. (2012): Community structure, trophic ecology and reproductive mode of oribatid mites (Oribatida, Acari) in forest ecosystems. Dissertation, University Goettingen
More information:  ediss.uni-goettingen.de
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Regionale Faktoren bestimmen die Gemeinschaftsstruktur der Hornmilben (Acari, Oribatida) mehr als der Waldtyp
Erdmann G., Scheu S., Maraun M. (2012): Regional factors rather than forest type drive the community structure of soil living oribatid mites (Acari, Oribatida). Experimental and Applied Acarology 57 (2), 157-169. doi: 10.1007/s10493-012-9546-9
More information:  doi.org
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Molekularer Nachweis von Nematoden in Oribatiden (Acari): Labor und Freiland-Experimente
Heidemann K., Scheu S., Ruess L., Maraun M. (2011): Molecular detection of nematode predation and scavenging in oribatid mites: Laboratory and field experiments. Soil Biology and Biochemistry 43 (11), 2229–2236. doi: 10.1016/j.soilbio.2011.07.015
More information:  doi.org
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Stabile Isotope als Marker zum Verständnis der Nahrungsbiologie von Hornmilben
Maraun M., Erdmann G., Fischer B. M., Pollierer M. M., Norton R. A., Schneider K., Scheu S. (2011): Stable isotopes revisited: Their use and limits for oribatid mite trophic ecology. Soil Biology & Biochemistry 43, 877-882. doi: 10.1016/j.soilbio.2011.01.003
More information:  doi.org
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Die mehrfache konvergente Evolution von Borke-lebenden Hornmilben (Oribatiden) deutet auf die herausragende Bedeutung ökologischer Faktoren im Laufe der Evolution hin
Maraun M., Erdmann G., Schulz G., Norton R.A., Scheu S., Domes K. (2009): Multiple convergent evolution of arboreal life in oribatid mites indicates the primacy of ecology. Biological Science 276 (1671), 3219-3227. doi: 10.1098/rspb.2009.0425
More information:  doi.org
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Der positive Zusammenhang zwischen der Dichte und der parthenogenetischen Reproduktion bei Oribatiden (ACARI) unterstützt die Bedeutung der 'Strukturierten Resourcen-Theorie der Sexuellen Reproduktion‘
Maraun M., Norton R. A., Ehnes R. B., Scheu S., Erdmann G. (2012): Positive correlation between density and parthenogenetic reproduction in oribatid mites (Acari) supports the structured resource theory of sexual reproduction. Evolutionary Ecology Research 14, 311-323
More information:  www.evolutionary-ecology.com
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Fettsäuremuster zur Bestimmung der Nahrungsbiologie von Hornmilben (Oribatida) in Buchen- und Fichtenwäldern
Wittlake I. (2012): Fettsäuremuster zur Bestimmung der Nahrungsbiologie von Hornmilben (Oribatida) in Buchen- und Fichtenwäldern. Bachelor thesis, University Goettingen

Scientific assistants

Prof. Dr. Mark Maraun
Project manager
Prof. Dr. Mark Maraun
Georg-August-Universität Göttingen
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