The Anal Plates of LarvalHydrellia pakistanae(Diptera: Ephydridae)

Abstract

Abstract The objective of this research was to describe the anal plates of the larval stages of the ephydrid fly, Hydrellia pakistanae Deonier, a biological control agent of hydrilla (Hydrilla verticillata (L.f.) Royle). This was accomplished using light microscopy coupled with a specialized staining technique; and scanning electron microscopy (SEM). AU 3 instars of H. pakistanae were collected from hydrilla cultured in outdoor concrete-lined ponds. To ascribe a function to the anal plates, a modified staining technique was employed that uses a 5% silver nitrate solution, which, upon ionization, binds with chloride ions suggesting an osmoregulatory function. Under light microscopy the two anal plates appeared smooth, flat crescent moon-shaped structures that encircled the anus of the larva. SEM revealed the anal plates to be relatively smooth with an undulating surface pattern possibly an artifact of the high vacuum conditions associated with the SEM. This may therefore indicate a difference in cuticle th...