Antennal and proboscis sensilla characteristics of Paranthrene tabaniformis (Lepidoptera: Sesiidae).

The poplar clearwing moth, Paranthrene tabaniformis (Lepidoptera: Sesiidae) is a serious wood-boring pest of several trees. The ultramorphology of the antennae and proboscis sensilla of adult P. tabaniformis was examined using scanning electron microscope to determine their structures and sex-specific differences. The results showed that the antennae of both sexes are composed of three segments: scape, pedicel and flagellum. Female antennae are clavate while male antennae are pectinate. The number of flagellomeres for females was significantly greater than for males. Seven different types of sensilla were identified on antennae of both males and females: Böhm sensilla, sensilla squamiformia, sensilla trichodea (three subtypes), sensilla chaetica, sensilla coeloconica, and sensilla auricillica (two subtypes), and apical sensors. Three different types of sensilla were found on the proboscis of adult P. tabaniformis: sensilla styloconica, sensilla chaetica, and sensilla basiconica (three subtypes). The sexual dimorphism difference in the number, distributional pattern, the length and the basal width of various sensilla on the antennae and proboscis were determined. This study clarifies the types and sexual dimorphism of the antennal and proboscis sensilla of adult P. tabaniformis and provides useful theoretical foundations for studies on behavioral mechanisms and functions of sensilla of P. tabaniformis. RESEARCH HIGHLIGHTS: Various types of sensilla on the antennae and proboscis of adults Paranthrene tabaniformis were observed. The sexual dimorphism of various sensilla on the antennae and proboscis were determined.

High local coordination symmetry around the spin center and the alignment between magnetic and symmetric axes together play a crucial role in single-molecule magnet performance.

A tetradentate 8-hydroxyquinoline-based acyl hydrazone ligand (HL1 = 8-hydroxyquinoline-2-carboxaldehyde-(aminourea)hydrochloride) was elaborately used to construct a mononuclear dysprosium complex DyCl3HL1·CH3OH (1) with a nearly ideal pentagonal bipyramid coordination geometry (D5h) surrounding the Dy(iii) ion to achieve the significant performance of single-molecule magnets (SMMs). Meanwhile, the isolated high local symmetry center was successfully kept intact and further bridged to a series of double bipyramid systems by two phenolic oxygen atoms of the acyl hydrazone ligands (HL1 and HL2 = 8-hydroxyquinoline-2-carboxaldehyde-(benzoyl)hydrazine), with the formulae [Dy2Cl4(L1)2(CH3OH)2]·4C5H5N (2) and [Dy2Cl4(L2)2]·2CH3CN (3). In addition, the monodentate co-ligand anion was replaced by a larger sterically hindered ligand and a bidentate monovalent ß-diketonate anion to generate [Dy2(tfo)4(L2)2(EtOH)2] (4), [Dy2(tta)4(L2)2(EtOH)2]·2(EtOH) (5) and [Dy2(dbm)4(L2)2(EtOH)2] (6) (tfo = trifluoromethanesulfonic acid, dbm = dibenzoylmethane, tta = 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione) with eight-coordinate geometry. Strikingly, the dynamic magnetic measurements revealed that complexes 1-3 did not display the expected significant SMM performance albeit they had high local symmetry. In combination with ab initio calculation, the alignment of the coordination symmetric axis and the magnetic easy axis dominates the molecular magnetic anisotropy, and the magnetic easy axis could be modulated by the distribution of coordination atoms with different electrostatic properties.