Subterranean Pitfall Traps: Is It Worth Including Them in Your Ant Sampling Protocol?

Table 1

Efficiency of the subterranean pitfall traps as a function of soil depth, time of trap exposure, and addition of vegetable oil on soil around traps.

Factor	Treatment	Number of traps (natural areas + crops)	Observed number of species (SD)	Estimated number of species (SD)	Observed number of cryptobiotic species (SD)	Estimated number of cryptobiotic species (SD)	Total number of ant species records	Traps without ants (%)
Duration	2 days	20 + 20	13 (±3.1)	21.8 (±3.0)	2 (±0.0)	3.0 (±1.0)	27	50.0
	7 days	20 + 20	17 (±2.1)	24.8 (±2.5)	5 (±1.6)	8.9 (±1.9)	37	40.0
Depth	20 cm	40 + 20	20 (±2.6)	29.8 (±2.9)	6 (±1.7)	10.9 (±2.1)	43	53.3
	50 cm	40 + 20	16 (±3.3)	27.8 (±3.4)	3 (±1.9)	4.0 (±1.0)	27	63.3
Vegetable oil	without	37 + 11	9 (±1.9)	14.9 (±2.7)	2 (±0.6)	3.0 (±1.0)	24	79.2
	with	38 + 12	13 (±3.2)	22.8 (±3.1)	2 (±0.0)	3.0 (±1.0)	30	68.0