Average speed of locomotion of Porcellio scaber on uncontaminated soil (chamber A) and soil contaminated with pyrethrin (chamber B) for isolated animals (A) and paired animals (B). In a free-choice experiment, isolated or paired animals could select between soil contaminated with pyrethrin and uncontaminated soil. In plot A, two extreme values for chamber B are not shown: at conc. 2.5 (value = 12.99) and conc. 10 (value = 25.77). Key: box: 25th, 50th, and 75th percentile; whiskers: value ≤ 1.5 IQR; o – outlier: 3 IQR ≤ value > 1.5 IQR; + – extreme: value > 3 IQR; * – significant difference between uncontaminated and contaminated soil, p < 0.05.