SEASONAL TROPHIC NICHE BREADTH AND OVERLAP IN A GUILD OF SIX MOST FREQUENT BEE SPECIES IN BAHAWALPUR, PAKISTAN

Abstract

Agonistic relationships in plant-pollinator assemblages are poorly understood as compared to mutualistic relationships. We estimated the floral resource competition in terms of seasonal trophic niche breadth and overlap among the guild of six most frequent bee species i.e., Ceratina smaragdula, Lasioglossum sp., Ceylalictus sp., Halictus sp., Apis dorsata and Apis florea in Bahawalpur (Punjab), Pakistan. The species exhibiting the maximum niche breadth had the minimum abundance in spring and summer seasons. The niche breadth of two solitary bees i.e., Lasioglossum sp. and C. smaragdula was higher than the social A. florae but they were much less abundant. Ceratina smaragdula showed the maximum pair-wise niche overlap with A. florea and Halictus sp. in spring and with Ceylalictus sp. in summer. Apis florea and A. dorsata had the maximum pair-wise niche overlap in both the autumn and winter seasons. No significant pair-wise niche overlap and interspecific competition was observed among all the six species in any season. This shows that pollination system in arid Bahawalpur is stable and less prone to competition and species loss.