A new technique for studying the stylet tracks of homopteran insects in hand-sectioned plant tissue using light or epifluorescence microscopy

Homopteran insects, such as aphids, psyllids and scales, inject a proteinaceous salivary sheath into their host plant tissue during feeding. This sheath, also referred to as a stylet track, remains in the tissue after the stylets are withdrawn, and is useful for studying plant resistance to insects and plant virus transmission. We describe a new method for studying stylet tracks. Hand microtome sectioned plant material was fixed and cleared in ethanol. The stylet tracks were stained with acid fuchsin and counterstained with aniline blue or fast green. The acid fuchsin stained stylet tracks were pink to red under light microscopy, and orange under TRITC epifluorescence. Stylet tracks in unstained sections autofluoresced under DAPI epifluorescence. This new technique is significantly faster and less complex than previous techniques, and permitted visualization of stylet tracks with light or epifluorescence microscopy within 1 hr of collecting fresh plant material. The technique was also applicable to a broad range of homopterans and plant taxa and provided excellent photomicrographs.