Although Diabrotica pest species have been well-studied in field corn, relatively little is known about adult host utilization by pest and nonpest species at corn-prairie interfaces. Our goal was to quantify seasonal patterns and adult host utilization of four Diabrotica species in remnant prairies and adjacent field corn in south central Nebraska. The study was conducted at five sites in 2001 and continued at four sites in 2002. Cucurbitacin vial traps, placed on transects, were used to monitor Diabrotica populations in prairies and adjacent corn. Visual surveys of available flowers and adult use of these flowers were also conducted throughout both summers. Habitat utilization varied significantly among the species over time. D. virgifera virgifera LeConte was present almost exclusively in cornfields, except in one prairie, where large numbers moved into pollinating ragweed in 2001. D. barberi Smith and Lawrence was also primarily found in field corn, but showed a greater tendency then D. v. virgifera to leave corn for a wide variety of pollen sources. D. cristata (Harris), a native prairie species, was predominantly trapped in prairies, but was occasionally observed in pollinating corn. D. undecimpunctata howardi Barber was frequently found in both prairies and corn on various pollen sources. Habitat type and pollen availability appeared to be key factors that influenced habitat choice by each species. These results increase our understanding of the ecological relationships of Diabrotica species and will help define if noncrop areas are important habitats for pest species.
Species 1: Coleoptera Chrysomelidae Diabrotica virgifera (western corn rootworm)
Species 2: Coleoptera Chrysomelidae Diabrotica barberi (northern corn rootworm)
Species 3: Coleoptera Chrysomelidae Diabrotica cristata
Keywords: prairie
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