Fig. 1

Schematic diagram of the positioning of pitfalls, here around three nests lined along a forest edge. We sampled the myrmecophiles inside a nest with an intranidal pitfall (i) and at the boundary (0 m) of a nest with a periphery pitfall (p). We placed an edge pitfall on the midpoint between two nests (along the forest edge direction). The captured myrmecophiles of this pitfall originate from either of the adjoining nests (see arrows). For both nests of this pair, a forest pitfall (f) was installed equidistant from the distance to the midpoint. Myrmecophiles found in this type of pitfall were mainly coming from the nearest nest (see single arrow). A nest which lies between two other nests in a forest fragment was part of two pairs of nests (here pair: nest1-nest2 and pair: nest2-nest3). For such a nest, two forest pitfalls were positioned at different distances: one at the half of the distance between nest 1 and 2 (midpoint distance x_1–2), and one at the half of the distance between nest 2 and 3 (midpoint distance x_2–3). Distance x varies from 0.6 to 25.6 m across the 20 tested nest pairs (distribution nests see Additional file 1: Fig. S1)