Diversity and Relative Abundance of Entomofauna of Four Ecologically Different Areas of Chittagong University Campus, Bangladesh

Abstract

The present study was conducted to find the relative abundance and diversity of insects in the four areas of the Chittagong University (CU) campus from January 2018 to December 2018. The entire study found six orders - Odonata, Orthoptera, Coleoptera, Lepidoptera, Diptera, and Hymenoptera. Three families under Odonata, two under Orthoptera, four under Coleoptera, five under Lepidoptera, five under Diptera, and three under Hymenoptera were collected from the four study spots. Among them, fifteen species of Odonata, seven species of Orthoptera, seven species of Coleoptera, thirty-five species of Lepidoptera, five species of Diptera, and four species of Hymenopteran were identified. The highest number of insects (478) were collected in January 2018, whereas the lowest number of insects (404) were collected in August 2018. The highest abundance (1598) of insects was found in spot 1 (ground area) and the lowest (990) in spot 2 (hilly area). Lepidoptera (2688) was the most dominant order in the four studied spots, followed by Odonata (1453), Orthoptera (505), Coleoptera (223), Diptera (202), and Hymenoptera (186). During the study period, the highest species richness was observed in Spot 3 (2.61 ± 0.01) and lowest in Spot 2 (2.03 ± 0.008); the highest species diversity was observed in Spot 1 (1.36 ± 0.02) and lowest in Spot 2 (1.09 ± 0.01); and the highest species evenness was observed in Spot 1 (0.53 ± 0.006) and lowest in Spot 2 (0.47 ± 0.006). Compared with the previous study, it can be concluded that the species diversity and abundance of Odonata, Orthoptera, and Lepidoptera were increased, whereas the diversity and abundance of Coleoptera and Hymenoptera were decreased. The abundance and diversity of insects depended on seasonal fluctuation and ecological and environmental conditions.