Bogusław Chachaj

Morphology of juvenile stages of three species of Scheloribatidae (Acari: Oribatida)

Abstract. The morphology of juvenile stages and ontogeny of Scheloribates holsaticus (Weigmann, 1969), S. initialis (Berlese, 1908), and S. pallidulus (C. L. Koch, 1841) were investigated. The juveniles of these species have excentrosclerites at similar gastronotal setae (c2, la, lp, and h1 in larva, and C2, la, lp, h-series, and P1 in nymphs), and solenidion &ohgr;1 on tarsus I strongly curved outwards, which are typical of Scheloribatidae, but they differ by body size and the shape of most gastronotal setae. The successive juvenile stages of S. holsaticus are the largest, while those of S. pallidulus are the smallest. The former species has most gastronotal setae barbed, while S. initialis and S. pallidulus have them smooth. The latter species has these setae thinner and more curved than other species, and pliable in distal parts. The adult of all these species have notogastral sacculi, but S. holsaticus has 13 pairs of notogastral setae, including pairs C2 and d-series, while other species have 10 pairs of setae, including pair C2.

Influence of sewage sludge composts with straw or ash on oribatid mites (Acari, Oribatida) from pine forest litter in laboratory conditions

Influence of sewage sludge composts with straw or ash on oribatid mites (Acari, Oribatida) from pine forest litter in laboratory conditions In a substrate obtained from municipal sewage sludge composts, the C:N ratio was decreased during the 12-month experiment. The amount of forest litter (layer 1 or 2 cm thick), used for fauna introduction, did not influence significantly the mean abundance of oribatid mites in sewage sludge compost. Oribatid mites tolerated compost alone or with straw, but were negatively influenced by addition of wood-ash. Abundance of oribatid mites in compost alone was increased from the 3rd month, and its maximum occurred in the 10th month. Abundance of oribatid mites in compost with straw was clearly increased since the 10th-12th month of the experiment. Generally the abundance of oribatid mites was mainly affected by Ramusella mihelcici, which was most abundant in compost alone and with straw (maximum abundance was above 100 000 individuals · m-2). However, species diversity of the mites was very low at the end of the experiment.

The influence of sheep, cattle and horse grazing on soil mites [Acari] of lowland meadows

Soil mites in lowland pastures grazed by sheep, cattle and horses and hay-growing meadows were investigated near Bydgoszcz. Samples were taken in spring, summer and autumn of 2001 and 2002 from the lower parts of plants (0-3 cm) and 2 soil layers, 0-3 cm and 3-6 cm. The grazing animals reduced the density of mites and species richness of Oribatida as compared to the control plots. The impact of sheep and cattle grazing on mites was higher than that of horses. Among the mites the Oribatida predominated, while the Gamasida were less abundant. Some species preferred the meadows while others preferred the pastures. Liebstadia similis predominated in the pastures grazed by sheep and cattle and Heminothrus peltifer – on those grazed by horses. Most mites inhabited the lower parts of plants; their density in the soil decreased with soil depth.

Colonization of hardwood and pine wood chips by mites (Acari), with particular reference to oribatid mites (Oribatida)

Abstract The study was conducted in the years 2011–2012, in a forest nursery in Białe Błota (Bydgoszcz Forest District). The experiment was established in a 20 m wide belt of trees within a 110 years old stand growing on mixed fresh coniferous forest site. Litter bags containing hardwood and pine wood chips were placed on mineral soil of microplots and covered with a 5 cm layer of litter. The pattern of chips colonization differed between mites belonging to different orders. Predatory Mesostigmata colonized hardwood chips gradually but they were present in high numbers in pine chips from the beginning of the study. Abundance of Actinedida fluctuated within the two-year study cycle. Contrary to that, oribatid mites, which were a predominant mite type, colonized both types of chips gradually, while preferring the pine ones. At the end of the study, the structure of mite communities and mite abundance in pine chips were more similar to forest soil than in hardwood chips. The experiment demonstrated that pine chips provided most oribatid mites with more favorable living conditions than hardwood chips, as they were colonized at a quicker rate and by a greater number of species. The most abundant oribatid mite in both substrates was a eurytopic Tectocepheus velatus that showed no clear preferences towards either of the substrates. Majority of oribatid mites, e.g. Oppiella nova, Metabelba pulverulenta, Oribatula tibialis, Chamobates schuetzi, Galumna lanceata, preferred pine chips. The only species with clear preference for hardwood chips was Eniochthonius minutissimus. A comparison of usefulness of hardwood and pine wood chips in revitalization of degraded soils based on bioindication approach indicated higher suitability of pine chips that are also more available in Polish forests.

The effect of mowing on moss mites (Acari, Oribatida) of Xerothermic Reserve Gruczno

The xerothermic plant communities mowing with different frequency and the brushwood of blackthorn overgrowing the not mowing surface of reserve were investigated. Populations of Oribatida were more numerous in the mowing terrains than in the brushwood. The number of species of Oribatida and the Shannon Index were similar in the investigated plots. In the swards surfaces the occurrence of the xerophilous species of Oribatida was found.