Insect Visitors of Lavender (Lavandula officinalis L.): Comparison of Quantitative and Qualitative Interactions of the Plant with Its Main Pollinators

Abstract

An inventory of insects visiting Lavandula officinalis flowers was established during three years (2009, 2010 and 2013) in a plot in the Constantine region (northeast Algeria). Three orders of insects were recorded on the flowers: Hymenoptera, Lepidoptera and Diptera. The majority (81 %) of taxa identified on the plant showed very low average abundances (≤1 individual/day) and 73 % of these taxa were bees and included the honeybee, Apis mellifera, the bumblebee, Bombus terrestris, Ceratina cucurbitina and two Megachilidae, Anthidium florentinum and A. manicatum. The bees had higher visitation rates than Lepidopterans (Iphiclides podalirius, Pieris rapae and Polyommatus dorylas). The ‘quantitative’ interaction of the plant with its main visitors, determined by the abundance and the visitation rate, showed that B. terrestris and A. mellifera are the most dominant pollinators of the plant. Analysis of the ‘qualitative’ component of the interaction of L. officinalis with the five major bees by counting pollen grains transported on their bodies revealed that B. terrestris, in addition to its dominance, was also the most efficient pollinator of the plant.