Oral exposure to up to 500 mg L⁻¹nCeO₂was sublethal for honeybees but altered the cholinergic system and induced other physiological responses.

Avoidance behaviour enables woodlice to escape suboptimal environmental conditions and to mitigate harmful effects of pollutants. However, several studies have shown that at least in some woodlice species the tendency to aggregate can lead to suboptimal responses as the between-conspecific attraction can outweigh the aversive stimuli. The present study evaluated the influence of gregariousness on the behaviour of Porcellio scaber in a heterogeneously polluted environment. The hypothesis was that the tendency for aggregation outweighs the tendency for exploratory activity, therefore animals in groups will be less active. Consequently, this will affect their avoidance of polluted environmental patches. To test this hypothesis, isolated individuals or pairs of individuals were monitored in free-choice arenas where animals could select between uncontaminated and pyrethrin-contaminated soils. Animals were video recorded for 3 h in darkness using infrared light and analysed for avoidance behaviour and locomotor activity. In general, isolated animals were more locomotory active and avoided the contaminated soil more than paired animals. It can be concluded that aggregation behaviour suppresses exploratory behaviour and consequently also the avoidance of polluted environments. This should be accounted for when interpreting results of avoidance tests with groups of gregarious animals, which may underestimate the effect of pollutants.

The increasing use of agricultural plastics (APs) and resulting accumulation of microplastics (MPs) in soils potentially affects soil organisms. This study assessed the effects of polypropylene MPs derived from commonly used black ribbon and white fleece mulching fabrics on four soil invertebrates. Animals were exposed to MP concentrations of 0.005 % - 5 % in Lufa 2.2 soil to assess effects on survival, reproduction (Enchytraeus crypticus, Folsomia candida) and behavior (Eisenia andrei, Porcellio scaber). Both MP types dose-relatedly decreased soil bulk density, and increased soil water holding capacity at high concentrations. The MPs from white fleece mulching fabric also increased soil pH at all concentrations tested. Reproduction was affected more by MPs from black ribbon fabric than from white fleece mulching fabric, significantly affecting enchytraeids at 1 % and 5 %, and at 5 %, respectively, and springtails only at 5 % for the black ribbon fabric MPs. Earthworms avoided soil at 5 % of the first or 0.5 % and 5 % of the second MP type. Isopods seemed attracted, but also showed different walking behavior at 5 % of black ribbon fabric MPs. MPs derived from commonly used APs were shown to affect soil properties at low concentrations and the reproduction and behavior of soil invertebrates.