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African Journal of Biotechnology

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Can Bt maize change the spatial distribution of predator Cycloneda sanguinea (L.) (Coleoptera: Coccinelidae)?

Thiago Alexandre Mota, Marcos Gino Fernandes, Eder Alcebiades Alegre, Maria Freire de Sousa, Elison FlorianoTiago, André Luiz Faleiros Lourenção

Abstract


Cultivation of Bt crops is an important tactic in integrated pest management. The effect of Bt maize on arthropod predators needs to be investigated because of the important role of these natural enemies in the absence of target pests. The objective of the present study was to generate information on the distribution model of Cycloneda sanguinea (L.) (Coleoptera: Coccinelidae) in Bt and non-Bt maize. A sampling field of 2.500 m2 area, divided into 100 plots, was used in this study. Five plants per plot, totaling 500 plants in each field, were studied. We counted the total number of adults every week, totaling six samples for each field (Bt and non-Bt). The aggregation index (variance/mean ratio, Morisita index, and exponent k of the negative binomial distribution) and Chi-square fit of the observed and expected values to the theoretical frequency distribution (Poisson, binomial, and negative binomial positive) revealed that, in both cultivars, the adults of C. sanguinea were distributed according to the random distribution model, which fits the pattern of Poisson distribution.

Keywords: Spatial distribution, natural enemy, lady beetle, Poisson.

African Journal of Biotechnology Vol. 12(42), pp. 6086-6090



http://dx.doi.org/10.5897/AJB2013.12941
AJOL African Journals Online