Occurrence, distribution and description of Harmonia dimidiata (Fabricius), a predacious Coccinellid from West Bengal, India

Abstract

Aim: To provide information about the occurrence and distribution of Harmonia dimidiata from West Bengal and facilitate the identification of species based on morpho-taxonomy. Methodology: Survey was done in different agro-climatic zones of West Bengal. Specimens were procured from their associated host plants, brought to the laboratory and investigated for taxonomic characters. Results: The morpho-taxonomy of H. dimidiata, as well as its host record, and distribution, were fully explained in the present investigation. It is most common in hill, terai, and old alluvial zone of West Bengal. They have been observed preying on Rhopalosiphum maidis (Fitch) in corn and Aphis gossypii (Glover). Interpretation: H. dimidiata population were recorded during survey from four different agro-climatic zones of West Bengal. They were observed to be preyed upon A. gossypii and R. maidis. The information about the biodiversity of H. dimidiata and their role as predator of numerous agriculturally important crop pests are extremely valuable that enrich our knowledge and immensely help in devising a pest management programme considering them as an important biocontrol agent. Furthermore, research on their biodiversity aids in learning about the predaceous behaviour in connection with the pest and crop populations, their reproduction and occurrence. This information is indeed praiseworthy while exploiting the ladybird species, H. dimidiata for a commercial biocontrol operation. Key words: Coleoptera, Coccinellidae, Harmonia dimidiata, Predaceous, West Bengal