How does the solitary bee Centris (Heterocentris) analis (Fabricius) find its nest?

Abstract

1. The knowledge of the sensory and cognitive abilities of insects is mostly restricted to studies with Drosophila and social hymenopteran species. Here, we investigated how a truly solitary bee localises and identifies its nest when spatial, chromatic, and chemical cues from and around its nest are manipulated.2. Our setup consisted of 30 standardised trap-nests made of bamboo canes, inserted in a vertical grey panel. After choosing a cane and memorising its initial position, returning females of Centris analis were individually presented to a new arrangement and had to rely on their sensory abilities to localise and recognise their own nests. During consecutive foraging trips, we tested the capacity of the bees for associative learning and the relative importance of visual cues, either spatial or chromatic, and chemical information, alone or in combination. We recorded the certainty of bees, their returns to the previous nest position (PNP) and the time needed to find their nests.3. Nests associated with a coloured stimulus resulted in the highest certainty when compared with treatments based on learning a new spatial position and/or a possible chemical profile of the nests. Time differences among treatments were mostly between those with and without a coloured stimulus. Returns to the PNP were higher when the precedent treatment was based on a fixed position.4. Centris analis have demonstrated to be flexible learners and to rely strongly on spatial and visual information, having odour as a secondary cue only used during nest identification.