Effect of infection on intraspecific interactions among amphipods. Shelter occupancy time A and number of aggression acts B shown by infected (black) or non-infected (white) D. haemobaphes (circles) and D. villosus (squares) in response to infected (red border) or non-infected (blue border) conspecifics. Results are back-transformed least squares means (±95% confidence intervals) predicted for significant effects by the General or Generalized Linear Models (analyses A–D in Table 1 and Suppl. material 1: Table S2). Treatments marked with the same lowercase letters did not differ significantly from one another.