UTTAR PRADESH JOURNAL OF ZOOLOGY

This study, for the first time, explored and identified the Hymenopteran insect biodiversity actively engaged in the pollination of Verbesina encelioides (Cavanilles) Bentham & Hooker (Asteraceae) in the Great Indian Desert of Thar in Rajasthan. This plant was observed as the principal source of nectar and pollen in the adverse conditions of the desert, hence need to be studied to establish a plant-insect relationship. The collection and identification of bees were done during the year 2019-20 which revealed that the flowers of Verbesina encelioides (Cavanilles) Bentham & Hooker attracted a total of 22 species of insect pollinators. Further identification studies showed that these 22 species belonged to 14 genera within six families. The identified genus was Apis Linnaeus (02 species), Braunaspis Michener (01 species), Campsomeriella Betrem(01 species), Ceratina Latreille (02 species),  Halictus Latreille (02 species),  Icteranthidium Michener (02 species), Megachile Latreille (03 species), Micromeriella Betrem(01 species), Nomia Latreille (02 species), Nomioides Schenck (01 species), Sphecodes Latreille (01 species), Trigonula Moure (01 species), Trachusa Panzer (01 species), Xylocopa Latreille (02 species). It was observed that the abundance of insect pollinators increased in the year 2020 as compared to 2019 because of decreasing anthropogenic activities and pollution in the study area due to COVID-19 lockdown. The higher value of the Simpson index of diversity i.e. 0.921 (2019) and 0.929 (2020) indicated that there was more than 92 % chance of capturing different insect species while random sampling. Shannon entropy (H) estimated were 2.79 and 2.86 respectively for the years 2019 and 2020. Results of Shannon entropy showed increased diversity of insects in the year 2020. Values of Gini indexes were 0.39 and 0.34 for the consecutive study years, representing inequality in the abundance distribution. The diversity of insect pollinators was also expressed by Renyi entropy (1.10; 1.5) and Hill number (16.31; 17.55) in the region. Verbesina encelioides (Cavanilles) Bentham & Hooker has been found as a good source of nutrition for the insect species in the Desert of Thar.