Assessment of Arthropod Biodiversity in Brinjal Agroecosystem with Special Reference to Insects and Spiders
Ejazul Haq *
Department of Plant Protection, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.
Parvez Qamar Rizvi
Department of Plant Protection, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.
*Author to whom correspondence should be addressed.
Abstract
Background: Brinjal (Solanum melongena L.) supports a diverse arthropod community comprising pest and beneficial groups.
Aims: The study aims to evaluate the biodiversity and relative abundance of arthropods associated with the brinjal agroecosystem and to record the occurrence of insect pests and beneficial arthropods at the order and family levels during two consecutive cropping years.
Study Design: Field-based observational study of arthropod diversity and abundance in a brinjal agroecosystem.
Place and Duration of the Study: Department of Plant Protection, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, Uttar Pradesh, India, during two consecutive cropping years.
Methodology: The experiment was carried out in an area measuring 25 m × 15 m. Twenty plots measuring 5 m × 3.5 m were marked on the land. Forty-day-old desi brinjal seedlings were transplanted into different plots at a spacing of 75 cm × 75 cm. Arthropods were collected at regular 15-day intervals, starting one month after transplanting and continuing until the end of the cropping season. Visual inspection, sweep-net sampling, and pitfall trapping were adopted for the collection and enumeration of arthropods. For visual observations, five plants were randomly selected from the respective plots. Five sweeps were performed per plot during each sampling period, and pitfall traps were placed to capture soil-dwelling arthropods. Specimens from all collected samples were identified and counted according to their higher taxonomic groups, i.e., order and family. Relative abundance, Shannon diversity, Simpson's diversity, and Pielou's evenness indices were calculated accordingly.
Results: A total of 39 arthropod families belonging to 12 orders were recorded. Hemiptera (relative abundance, 40.98-42.12%) was the most abundant, followed by Coleoptera (14.61-15.75%), Hymenoptera (9.55-10.88%), Araneae (7.99-8.19%), Acarina (6.08-6.89%), and Lepidoptera (5.89-6.18%). Aphididae was the most abundant family within Hemiptera (10.24-11.18%), whereas Coccinellidae was the dominant family within coleoptera (7.59-8.51%). Beneficial arthropod families were also recorded.
The values for Shannon diversity (H') ranged from 3.096 to 3.141, while Simpson's diversity index (D) and Pielou's evenness index (J) ranged from 0.939 to 0.943 and from 0.845 to 0.857, respectively, indicating relatively stable arthropod diversity across the two consecutive years.
Conclusions: The present findings revealed that the brinjal field supported diverse pest and beneficial arthropod fauna. The presence of natural enemies, together with relatively stable diversity indices, indicates the need to conserve this biodiversity through the adoption of eco-friendly pest management strategies aimed at sustainable brinjal production.
Keywords: Brinjal, Solanum melongena, arthropod biodiversity, insect pests, spiders, natural enemies, relative abundance, Shannon diversity, Simpson’s diversity, integrated pest management