Composition and Electrophysiological Activity of Constituents Identified in Male Wing Gland Secretion of the Bumblebee Parasite Aphomia sociella

Abstract

Male wing gland secretion and volatiles emanating from calling males were investigated in the bumble bee wax moth, Aphomia. sociella, using comprehensive two-dimensional gas chromatography-mass spectrometry (GCxGC-TOF-MS), gas chromatography-infrared spectroscopy (GC-FTIR), enantioselective gas chromatography, electroantennography (EAG), gas chromatography with electroantennographic detection (GC-EAD), and NMR. GC-EAD analysis of the male wing gland secretion revealed seven active areas, corresponding to 1-hexanol (1), 2-phenylethanol (2), [(R),(Z)]-nona-2,6-dien-4-olide (3), [(S),(Z)]-nona-6-en-4-olide (4), mellein (5), phytone (6), and a mixture of C(18) fatty acids (7). Solid-phase microextraction (SPME) confirmed the presence of 2-phenylethanol, nona-2,6-dien-4-olide, nona-6-en-4-olide, mellein, and phytone in volatiles emanating from a calling male. Though the abundance of these compounds slightly differed in SPME and gland secretion analysis, nona-2,6-dien-4-olide and mellein dominated in both samples, followed by 2-phenylethanol, nona-6-en-4-olide, and phytone. The strong antennal responses elicited by components of the secretion suggest that one or more of these compounds constitute the sex pheromone. Both sexes perceived male wing gland secretion, with females being significantly more sensitive compared to males.