Coccinellid populations in field corn and sweet corn, Zea mays L., were monitored from 1999 to 2001 in New York to evaluate the importance of several abiotic and biotic factors in the temporal and within-plant distributions of the most abundant species. Coleomegilla maculata (DeGeer) and Harmonia axyridis (Pallas) were the only abundant species and adult and larval populations of both species had distinct temporal and within-plant distributions. The factors of crop maturity, aphid density, planting date, corn type, nearby vegetation, and time of day were found to alter the temporal or within-plant distribution of each species differently. Some conditions resulted in higher encounter rates between these species than other conditions. While the distribution of each population was somewhat unique, some C. maculata and H. axyridis shared time and space, providing the potential for intraguild predation. An encounter between H. axyridis and C. maculata was most likely to occur when the corn had high aphid populations during pollen shed. While intraguild predation may reduce C. maculata populations in corn, a diverse landscape provides unique habitats for these species, minimizing the impact of intraguild predation on the survival of C. maculata.
Species 1: Coleoptera Coccinellidae Harmonia axyridis (Multicolored Asian lady beetle)
Species 2: Coleoptera Coccinellidae Coleomegilla maculata
Keywords: intraguild predation
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