Nesting Behaviour of Three Species of Ceratina Pollinating Cashew

Abstract

Cashew is a cross-pollinated crop requiring insects primarily bees for successful pollination. Honey bees and several native bees are important pollinators of cashew. Among the native bees, Braunsapis spp. and Ceratina spp. are commonly present in the study region. Under Ceratina, three species namely, C. hieroglyphica, C. bingami and Ceratina sp. 1 have been recorded on cashew and their nesting behaviours have been documented under the present investigation. The nests of these three bee species have been found in dried twigs/ sticks of cashew trees. Nests of all three species had smooth circular entrances, but the diameter of the entrance hole varied with species. It was just 1.0-1.5 mm for Ceratina sp. 1, 2.5-4.0 mm for C. hieroglyphica, 3.5-4.0 mm for C. binghami. The nest, as well as cell dimensions, varied with species. In all three species, older cells were at the bottom of nests, while young ones were towards the entrance. Each egg was laid on the pollen provided in an individual cell and sealed with powdered wood particles. Guarding at nest entrance by adult female blocking with its abdomen was commonly noticed in the nests. The number of individuals in a single nest varied between 1-14, 1-7 and 1-19 for C. hieroglyphica, C. bingami and Ceratina sp. 1, respectively. The trees with the pruned cut ends had more number of bee nests compared to unpruned ones. The study suggests that increasing smooth cut ends in the sticks by pruning and leaving the dried sticks in the cashew plants wherever possible can facilitate the native bees to make nests in them thereby they can be conserved.