The influence of emptying frequency of pitfall traps on the capture of epigeal invertebrates, especially Pterostichus madidus (Coleoptera:Carabidae).

Abstract

Pitfall trapping has many inadequacies but remains the most used method of collecting epigeal invertebrates. Trap data are often standardised to numbers per day, however, invertebrates already captured may cause attraction making this standardisation invalid. To test for attraction, pitfall traps were emptied at different frequencies and the impact on capture examined. The catch comprised 83% Coleoptera, of which 90% were Pterostichus madidus Fabricius. Traps which were emptied after six or nine days had higher capture rates of P. madidus than those emptied daily or every two or three days. Staphylinidae and Araneae catches were unaffected by emptying frequency.