Abundance , Activity and Diversity of Insects Associated with Flower of Sal (<I>Shorea robusta</I>) in Midnapore , (Arabari) West Bengal , India

Abstract

The sweet fragrance of Sal flower attracts the varied groups of insects. In the present study , the insects visiting the Sal flowers during blooming period (i.e. March) were studied for two consecutive years. (1985-86) during morning , noon and afternoon periods in the dry deciduous natural Sal forests ofArabari , Midnapore , West Bengal , India. As many as 84 different types of species representing 44 families under 7 orders viz. , Coleoptera , Diptera , Hemiptera , Homoptera , Hymenoptera , Lepidoptera and Thysanoptera were collected. Insects were identified. Their abundance , varieties and activities were studied. Availability of the insect per hour were recorded. Percentage of different groups were calcuated and diversity indices (D' values) of the species were analyzed. In the general the '0' values were highest in the morning followed by afternoon and noon. From the study it clearly appears that Sal flowers are entomophilious in nature and most active pollinators are some dipteran flies an4 bees. However , almost all the insects appear on flower heads , play some role in this pollen transfer process. And different pollinators exert varied selective forces as a result of their effectiveness in pollen transport system.