Comparing the pollen forage pattern of stingless bee (Trigona iridipennis Smith) between rural and semi-urban areas of West Bengal, India

Pollen loads of Trigona iridipennis Smith were analyzed on a comparative basis between rural and semi-urban areas of Paschim Medinipur district, West Bengal in order to explore the botanical origin of pollen loads and pollen foraging activity of the bee species. Altogether 72 plants belonging to 37 families were recognized as pollen resources for the bee species. Major pollen contributing families were Myrtaceae, Fabaceae, Arecaceae and Cannabaceae. Very frequent pollen types were Borassus flabellifer, Brassica juncea, Delonix regia, Eucalyptus tereticornis, Syzygium cumini and Trema orientalis. The diversity of pollen type remains higher in rural areas of Garhbeta in comparison to the semi-urban areas of Midnapore town. Majority of natural forest trees, weeds and cultivated crops those were detected from rural areas were not recognized within the pollen spectrum in semi-urban areas of Midnapore town. In general, we found that T. iridipennis preferred tree habit with small sized flowers as a source of pollen. The most common shapes of the bee visited flowers were dish-like and brush-like, and the preferred flower colours were yellow, white or cream. Foraging activity of the bee species does not significantly differ between the two regions. However, activity differed significantly according to daytime hours as well as month wise in both the sites. Maximum activity observed in late morning, while early morning showed the lowest. Monthly activity was higher during the months of November to April, whereas activity was very low in July and August.