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The effects of eight polycyclic aromatic compounds on the survival and reproduction of the collembolan Folsomia fimetaria L. were investigated in a well-characterized Danish agricultural soil. With the exception of acridine, polycyclic aromatic hydrocarbons (PAHs) and neutral N-, S-, and O-monosubstituted analogues showed similar toxicities to soil collembolans when the results were expressed in relation to total soil concentrations (mg/kg). The estimated concentrations resulting in a 10% reduction of reproductive output (EC10 values) were based on measured initial concentrations and were for acridine 290 mg/kg, carbazole 10 mg/kg, dibenzofuran 19 mg/kg, dibenzothiophene 7.8 mg/kg, fluoranthene 37 mg/kg, fluorene 7.7 mg/kg, phenantrene 23 mg/kg, and pyrene 10 mg/kg. When the EC10 values were converted to soil pore-water concentrations, they showed a highly significant correlation (r2 = 0.71, p < 0.01) to no-observed-effect concentrations for the freshwater crustacean Daphnia magna, as estimated by a quantitative structure activity relation (QSAR) for baseline toxicity (nonpolar narcosis). Only carbazole and acridine were more than two times more toxic (4.9 and 3.1, respectively) than expected from the Daphnia QSAR data. The latter result indicates that the toxicity of the tested substances is close to that expected for compounds with nonpolar narcosis as the mode of action. However, the relatively large uncertainties in the extrapolation method prevent final conclusions from being drawn.

A group of specialized setae on the sixth abdominal segment (foil setae) of Isotomidae are described. A survey of more than 100 species of family Isotomidae shows these setae to occur in certain species of several genera of subfamily Anurophorinae s.str. They are probably derived from macrosetae and are characterized by their unique shape. They appear to have evolved in several lineages and have fixed locations on the body.

Summary Data on the number of macrochaetae of the main segments (Th. II–Abd. IV) of the body in 76 species of Folsomia are summarised. Only thoracic tergites II—III show variation in number of macrochaetae, as the conditions 1,1, 2,2 and 1,2 were found in the material studied. The last variation was seen in three groups of species, and has probably been derived independently.

In a project investigating the ecotoxicity of polycyclic aromatic compounds (PACs), we have previously reported on the sublethal toxicity of eight PACs to springtails (Folsomia fimetaria) and enchytraeids (Enchytraeus crypticus). The model substances included four polycyclic aromatic hydrocarbons (PAHs) and four N-S-O-heterocyclies. Here, new data are presented on the effects of PACs on the survival and growth of the earthworm Eisenia veneta, showing that, in general, earthworm growth was reduced at PAC concentrations above 25 mg/kg soil dry weight. The E. veneta tests were performed using the same soil type and very similar test conditions as for the F. fimetaria and E. crypticus tests, thus providing a good opportunity to compare the sensitivity of these three organisms. Species sensitivity was examined using the 50% reduction in survival (LC50 values) and no-observable-effect concentrations (NOEC values) for growth or reproduction as endpoints. The difference between the least and most sensitive species was generally much larger for LC50 values as compared to the NOEC values, suggesting a higher degree of uncertainty when extrapolating from one species to another for the LC50 data. For the NOEC data, relatively small differences in sensitivity was observed, but as a rather consistent pattern, F. fimetaria was the most sensitive and E. crypticus the least sensitive species. However, one substance (acridine) showed specific toxicity toward E. veneta, which was more sensitive than the two other species by more than one order of magnitude.

Potapov, Mikhail, Babenko, Anatoly, Fjellberg, Arne (2006): Taxonomy of the Proisotoma complex. Redefinition of genera and description of new species of Scutisotoma and Weberacantha (Collembola, Isotomidae). Zootaxa 1382 (1): 1-74, DOI: 10.11646/zootaxa.1382.1.1, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.1382.1.1

Isotominella geophila Delamare Deboutteville, 1948, from Massif Edough in Northeast Algeria, has been found for the second time and is redescribed. It is separated from all other genera of Isotomidae by the following combination of characters: absence of eyes and pigment, PAO oval, not subdivided, shorter than width of antennal base, dens partially crenulated, dental chaetotaxy with more than six setae (13+4), posterior central S-setae on thoracic tergite II to abdominal tergite IV in p-row, S-seta on abdominal tergite V not thickened and mucro bidentate. This species exhibits sexual dimorphism.

Variations in the rate of moulting and of faecal pellet production by Cryptopygus antarcticus (Willem), collected from Signy Island in the maritime Antarctic, were rheasured over temperatures of 0? to 20'C. Over the range 5? to 15'C total faecal pellet production between moults was similar; at 00C there was little feeding activity, whilst mortality was high at 20TC. The temperature of maximum moulting frequency is lower for this species than for temperate Isotomidae, suggesting cold adaptation of its moulting behaviour. Growth of individual specimens at 100C was measured from mandibles recovered from shed exuviae after each moult, using a linear relationship between body length and mandible length. At a body length of 1040-1134 gm, individuals either increased or decreased in size at subsequent moults. The results suggest that the minimum age of the largest specimens of Cryptopygus on Signy Island is probably 3-7 yr.

Complex antennal sense organs of males in the Collembola suborder Arthropleona are illustrated and described for the first time. In addition the species Hydroisotoma schaefferi (Krausbauer) is redescribed.

Trophic level relationships of a soil invertebrate community were determined using the transient behavior of cesium-137 in experimental soil microcosms. Feeding rates were estimated from radionuclide mass balance equations using radiocesium uptake coefficients, equilibrium concentrations of 137Cs in consumers, and 137Cs composition of food bases. The fungivore trophic level included Scatopsidae larvae (Diptera), Enchytraeidae (Annelida), Entomobryidae and Onychiuridae (Collembola), Rhodacaridae (Mesostigmata), and Oribatulidae, Camasiidae, Carabodidae, and Cymbaeremaeidae (Oribatei). Approximately 60 per cent of the total faunal biomass occurred in the fungivore trophic level. Fungivores averaged 7.0 ? 2.4 per cent dry body weight ingested per day. Cecidomyiidae larvae (Diptera), Diplopoda, Isotomidae (Collembola), Uropodina, and Phthiracaridae (Oribatei) were determined to be surface-feeding saprophages. Subsurface-feeding saprophages included Symphyla, Cillibidae (Uropodina), and Palaeacaridae and Epilohmannidae (Oribatei). Surfacefeeding saprophages averaged 1.0 ? 0.4 per cent dry body weight ingested per day. Feeding rates were not calculated for saprophages feeding within the mineral soil horizon. Predators included Dolichopodidae larvae (Diptera), gamasine mites, and the Scutacaridae and other prostigmatid mites. Predators averaged 2.5 ? 1.0 per cent dry body weight ingested per day.