Journal Article

Abundance and Diversity Indices of Aestivating Insect in Rice-Field Soil Exposed to Different Agro-Chemical Practices in Minna Metropolis, Nigeria

Abstract

Abundance and diversity indices of aestivating insect in soil exposed to different agro-chemical practices in Minna Metropolis, during dry season of the year 2013 was investigated. The result revealed three insect Orders namely, Hymenoptera, Coleoptera and Hemiptera with the following abundance 45 (56.25%), 25 (31.25%) and 10 (12.50%) across the rice-field categories sampled. However, category A (No agro-chemical application), B (Only fertilizer application) and C (Both fertilizer and herbicide application) recorded 35.00, 38.75 and 26.25 % respectively, for all the insect orders. Only order Hymenoptera was recorded across the 3 rice-field categories sampled. Furthermore, Simpson and Margelef diversity indices revealed that category B is the most diverse with an index value of 0.666 and 0.582 respectively. In terms of Insect Order diversification, Simpson, Shannon and Margelef diversity indices revealed no diversity recorded for Order Hemiptera across the rice-field community during the aestivation period. Although, the 3 diversity indices above have all place Order Hymenoptera as the most diverse compare to others. Berger-parker diversity indices also revealed had the lowest dominance and Hymenoptera had the highest with index value of 1.000 and 0.466 respectively. The findings of this study have buttressed insect aestivating process in rice-fields during arid season in Minna, as influenced by the previously retained soil agrochemical inputs, in clearer perspective, more so, the findings have also established the baseline implication of agro-chemical practices as one of the anthropogenic factors, influencing sustainable increase in aquatic insect population in rice-field ecosystem in Minna and other areas with similar rice farming agronomic practices.

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