Species composition, abundance, and activity of predatory arthropods in carrot fields, Canterbury, New Zealand

Abstract

Pitfall trapping (November 1993 to April 1994) and Malaise trapping (January to June 1995) were carried out to study the predatory arthropod fauna in carrot fields at four sites in Canterbury, New Zealand. Staphylinidae (rove beetles), Linyphiidae (money spiders), Lycosidae (wolf spiders), Phalangiidae (harvestmen), and Carabidae (ground beetles) were the most abundant predators. At Lincoln, spiders, staphylinids, harvestmen, and carabids comprised 68, 13, 11, and 2.6 percent, respectively, of all total predaceous arthropods in pitfall traps. At Killinchy (30 km from Lincoln) these four taxa constituted 77, 8.5, 0.7, and 6.5 percent of the pitfall trap catches. Overall, a total of 33 staphylinid species was recorded, including one, Ocypus ater (Gravenhorst), which was new to New Zealand. The total number of predators caught in pitfall traps declined in March and April. In pitfall traps the abundant species were the staphylinids Amischa analis (Grav.), A. nigrofusca (Step.), Atheta fungi (Grav.), A. amicula (Step.), and Xantholinus linearis (Oliver); the carabids Meta‐glymma monilifer Bates and Holcaspis angustula Chaudoir; the spiders Lepthyphantes tenuis (Blackwall), Erigone spp. and ’Lycosa’ hilaris Koch; and the harvestman Phalangium opilio L. In Malaise traps, abundant staphylinid species were Tachyporus nitidulus (Fab.), Amischa decipiens (Sharp), and Atheta fungi (Grav.). The seasonal activity and abundance of the dominant species are described, and their potential importance in control of carrot rust fly (Psila rosae F.) and pests in other crops is discussed.