Evaluation of artificial nesting materials for domiciliation of Megachile spp. and their impact on pigeonpea yield

Abstract

A field investigation was conducted to evaluate the nesting preferences of Megachilid bees and their contribution to pigeonpea yield under artificial domiciliation. Two nesting substrates—Sarkanda sticks (Saccharum spontaneum) and bamboo drilled blocks were monitored at 15‑day intervals. Sarkanda sticks exhibited higher acceptance (4.53%), whereas bamboo blocks remained unused throughout the study. Nesting activity peaked in October 2024 with 21 nests (3.96%), followed by November with 16 nests (3.01%). Four Megachilid species were recorded: Megachile lanata, M. sculpturalis, M. bicolor, and M. disjuncta. Among these, M. lanata was dominant, with activity ranging between 2.19–3.12 individuals per minute per square meter. Diversity indices revealed moderate species diversity (Shannon–Wiener index H′: 1.31–1.34; Simpson’s diversity D: 0.70–0.73) coupled with high evenness (0.94–0.97), indicating balanced species distribution across nesting sites. The impact of domiciliation on crop productivity was evident. Pigeonpea plots with artificial nests recorded significantly higher yields (13.89–14.68 q/ha) compared to control plots without nests (9.47 q/ha). This enhancement underscores the role of Megachilid bees as efficient pollinators, directly contributing to improved seed set and yield. Overall, the study highlights Sarkanda sticks as a suitable substrate for domiciliation of Megachilid bees and demonstrates the potential of managed nesting to augment pollination services in pigeonpea. Adoption of such practices could serve as a sustainable strategy to enhance legume productivity while conserving native pollinator diversity.