Ground beetles were collected by using pitfall traps, which were emptied every 20 days, from April to December in 2005, in order to obtain a “year’s sample”. In this way the different seasonal period of activity of each species was intercepted by the traps, so avoiding the possible bias affecting the samples (as in [28, 51]; see also ). This is a standardized sampling method successfully applied since many years by many authors (see  and literature therein).