“…This finding has been corroborated in other studies with different ant species (Duncan & Crewe, 1993;Lighton et al, 1993;Duncan & Lighton, 1994;Duncan, 1995Duncan, , 1999, as well as other insects such as flies (Berrigan & Lighton, 1993, mites (Lighton & Duncan, 1995) and wasps (Duncan & Lighton, 1997 Usually, the cost of carrying a load has been evaluated using different laden and unladen individuals (exception: Nielsen, 2001) and artificial loads, except for a few studies, e.g. (Bartholomew et al, 1988;Duncan & Lighton, 1994;Fewell et al, 1996;Duncan, 1999). The second study was the only one that measured the cost of internal load carriage of a natural load, i.e.…”