CHANGES IN ABUNDANCE OF NATIVE AND ADVENTIVE COCCINELLIDAE (COLEOPTERA) IN ALFALFA FIELDS, IN NORTHERN NEW JERSEY (1993–2004) AND DELAWARE (1999–2004), U.S.A

Weekly and biweekly sweep net collections were made near Blairstown, New Jersey, and Newark, Delaware (both in the U.S.A.), for 12 and 6 consecutive years, respectively. At Blairstown, only one non-native coccinellid [Coccinella septempunctata (L.)] was common when this research was started in 1993, one [Propylea quatuordecimpunctata (L.)] had recently appeared, and two others [Harmonia axyridis (Pallas), Hippodamia variegata (Goeze)] were detected later during the 12-year study. All of these four species were adventive, having established themselves through commerce, three species at inland ports, and one near a coastal seaport. The most numerous adult lady beetles at both locations were two native species, Coleomegilla maculata (F.) and Hippodamia parenthesis (Say), and three adventive species, P. quatuordecimpunctata, C. septempunctata, and H. axyridis. Six species were occasionally swept at Blairstown - one adventive species (H. variegata) and five native species [Cycloneda munda (Say), Cocci...