Confirmation of Host Plant of Cave‐Dwelling Cixiid Planthoppers (Hemiptera: Cixiidae) by Histological Sectioning of Fig Roots

The food sources of cave‐dwelling insects are difficult to document, and those of root‐feeding cixiid nymphs (Hemiptera: Cixiidae) particularly so because of their tendency to jump from their substrates upon the slightest disturbance. By histologically staining the stylet sheath left by Oliarus sp. feeding on Ficus roots, we establish the host association beyond doubt. Histological sections also demonstrate that Oliarus feeds in the cells of the endoderm and within the xylem vessels. The technique we describe can be used to determine host relationships for cave‐dwelling Cixiidae in general, providing an additional angle for the study of the evolutionary history of cave adaptation in this group.