Antennal Sensilla of Workers of Melipona quadrifasciata anthidioides Lepeletier (Apidae, Meliponini) Removing and non-Removing Dead Brood: Morphology, Morphometry and Quantity

The sophisticated chemical communication of bees allows the natural control of pathogens and diseases in the colony, through hygienic behavior (HB), in which dead or sick brood are removed, improving colony health. In this study, we investigated the morphology, morphometry and quantity of sensilla of workers of Melipona quadrifasciata anthidioides, removing and non-removing dead brood in the HB test. From the micrographs obtained through scanning electron microscopy, the sensilla trichodea (STr), basiconic (SBa), placodea (SPl), coeloconic (SCo), campaniform (SCa), ampullacea (SAm), cetica (SCe), chaetica (SCha), and its subtypes were morphologically characterized. We highlight the identification of sensilla STr 7, setae (SSe), placodea 2 (SPl 2), Bohm's bristles (BhB) and branched bristles (BB), not previously reported in this species. Morphometry indicates that removing workers have a longer average length of the antenna and its segments than non-removing bees, as well as the length of the SCo, SPl 1, SSe, STr 1, STr 2, STr 3 and STr 4 sensilla. Regarding the quantification of sensilla, there was no significant difference between the groups. Considering that chemical stimuli incite bee HB, sensilla may play a fundamental role in hygienic bee lineages, and there is a need to further explore this relationship to understand bee HB.