Journal of Environmental Biology

Elytral polymorphism of Cheilomenes sexmaculata (Fabricius), Harmonia octomaculata (Fabricius), Coccinella septempunctata Linnaeus and Propylea dissecta (Mulsant) (Coleoptera: Coccinellidae) in the Gangetic Alluvial Plain Zone of West Bengal, India

T. Majumder, A. Manna, I. Zaman and K. Roy*     

Department of Agricultural Entomology, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur-741 252, India

Received: 03 July 2024                   Revised: 14 September 2024                   Accepted: 27 February 2025

*Corresponding Author Email : roy.kusal@bckv.edu.in                     *ORCiD: https://orcid.org/0000-0002-5179-2373                     

Abstract

Aim: To provide information on the occurrence of polymorphic variants of four different ladybird beetles (Cheilomenes sexamculata, Harmonia octomaculata, Coccinella septempunctata and Propylea dissecta) in West Bengal and to facilitate identification based on various morphological characters.

Methodology: Survey was carried out during 2022-2023 in the Gangetic Alluvial Plain Region of West Bengal. Fourteen localities of the agro-climatic zone were selected to survey for the collection of coccinellids. Adult specimens of four different ladybirds were collected, brought to the laboratory and preserved. Slides of different morphological body parts were prepared.

Results: In total, five morphs of C. sexmaculata, eight morphs of H. octomaculata, six morphs of C. septempunctata and four morphs of P. dissecta were recorded. These morphs comprised both melanic and non-melanic forms.

Interpretation: Polymorphic elytral pattern may lead to the ambiguity in correct identification of a ladybird species. The outcome of the study will definitely lead the researchers to arrive at the precise identity of the mentioned ladybird species, which is considered to be a criterion in any study allied to biological organism.

Key words: Coccinellid, Coleoptera, Elytral polymorphism, Diagnostics, Illustrative guide, West Bengal

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