Bee sampling efficiencies of three different methods in a forested ecosystem in Southern West Bengal, India: A comparative study

摘要

The study of bees has necessitated the evolution of several different techniques of sampling bees from the wild, which can be broadly classified into active and passive sampling methods. Traditionally, active sampling using sweep nets and passive sampling involving the use of several passive traps, viz., vane, pan/bowl, malaise etc., have long been in application. Adapting to the conditions of the ecosystems under study, passive sampling methods have been modified and improved upon in various innovative ways. The present study compares the sampling efficiencies of nets, bowls, and one such innovative height-adjustable modification of passive bowl trapping in sampling bees in a forested ecosystem in West Midnapore district of West Bengal, India. A total of 228 bees representing 13 species and 2 families were caught by the three methods over three seasons spanning one year following monthly sampling efforts. Results revealed that there was a significant interaction between methods and seasons on theaverage number of bees sampled. Different sampling methods also differed in the proportions of the various nesting guilds of bees that could be sampled by them. Bee assemblages sampled by the three methods displayed varying ecological indices, includingsignificantly different Shannon H2. This first-of-its-kind study in this ecosystem concludes that a combination of different sampling methods is necessary for comprehensive sampling of native bee fauna in similar forested habitats prevalent across lateritic south West Bengal, India.