High resolution ultrastructural investigation of insect sensory organs using field emission scanning electron microscopy

Field emission scanning electron microscopy (FESEM) is an extremely useful viewing technique for examining ultrastructural features pertaining to insect sensory organs (sensilla) at high magnifications. In comparison to conventional scanning electron microscopy (SEM), FESEM operates superiorly at lower accelerating voltages, offering greater resolution capabilities at higher magnifications and providing greater enhancement of surface cuticular structures (e.g., pores), often unattainable using conventional SEM. Overall, this technique provides a means for unambiguously classifying sensillum types (e.g., those used in the detection of olfactory/smell, gustatory/taste, mechanosensory/touch, and thermo-hygrosensory/temperature-humidity cues) based on external, morphological, cuticular features, such as the absence or presence of cuticular pores. The ability to resolve such external, ultrastructural features at higher magnifications (> 50,000 x) allows inferences to be made about the putative functions of these sensilla.