Análise morfológica das sensilas antenais das abelhas Melipona interrupta Latreille, 1811 e Melipona seminigra Friese,1903

Abstract

Sensilla are sensory structures found in flagellomeres in greater quantity in antennas and extent in other parts of the head. The sensilla have multiple sensory modalities, are categorized as mechanoreceptors, chemoreceptors, thermoreceptors, or hygroreceptors and are CO2-sensitive. This study aimed to identify the types of sensilla and their distribution along the antenna present in individuals of both sexes and castes of stingless bees Melipona interrupta and M. seminigra. The bees were obtained in colonies from Meliponário do Grupo de Pesquisas em Abelhas (GPA) of the Instituto Nacional de Pesquisas da Amazônia (INPA). The antennas were removed and fixed in Zamboni solution and remained in this fixative for 24 hours; washed with saline, 0.9% NaCl, were then dehydrated in acetone solution with increasing concentrations (50%, 70%, 90%, 95% and acetone PA) for 10 minutes each; PA acetone three washes were done in the last material was remained in 0.5 mL of acetone to evaporate all content. The antennas were mounted on stubs for plating with gold and photographed in a scanning electron microscope in the Thematic Laboratory Microscopy Optics and Electronics - LTMOE at INPA. Thirteen different types of sensillum were found in M. interrupta and M. seminigra individuals: sensilla trichodea (ST) (trichodea type I to VI), setae, chaeticum, basiconic, placoidea, coeloconic, ampullacea and campaniform. In both species the sensilla trichodea type I is the most abundant found between the sexes and castes, the sensilla STIII are exclusively found of the first segment, that in males the first antennal segment is smaller than the females, but there is no significant differences in number of STIII between the sexes. STII can be found the first segment to the distal segment is greater number in female of both species. STV is exclusive of the last antennal segment in the distal segment in both species and sexes, sensilla basicônic is exclusive to females, and the number of workers of SB in M. interrupta and M. seminigra increases every segment near the antennal apex. The function chemoreceptor sensillum this must be exercised by another sensilla in males, such as the sensillum placodea, because it is present in larger amount in the male antenna in both species. The other sensilla are distributed homogeneously by the antenna. This work represents a breakthrough in understanding the sensory organs of M. interrupta and M. seminigra and can serve as a basis for further work in this area with this or other insect species, however, more complementary studies to scanning electron microscopy and electrophysiology, electroantennography should be performed to investigate what these sensilla functions play in the studied species.