Morphological description of the mouthparts of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae)

Morphology of the mouthparts of the spittlebug Philagra albinotata Uhler (Hemiptera: Cercopoidea: Aphrophoridae)

“…The sharp end and the abundant protrusions of the mandibular stylets are structures specialized to pierce plant tissues while probing and are also present in other hemipteran insects (Forbes, 1969;Ullman and McLean, 1986;Zhao et al, 2010;Garzo et al, 2012). The limited variation observed among Auchenorrhyncha in the shape of the stylets may be due to the strong functional constraints on these structures and reflects the similar phytophagous feeding habits among species within the group.…”

“…There are a number of morphological similarities in the mouthparts of this insect to those of Auchenorrhyncha species described previously (Anderson et al, 2006;Boyd, 2003;Forbes, 1969;Pollard, 1973;Garzo et al, 2012;Liang et al, 2013;Rosell et al, 1995;Zhao et al, 2010). The basic structure of the mouthparts consists of a cone-shaped labrum covered with some triangular spines, a cylindrical, three-segmented labium with abundant different types of sensilla mainly symmetrically distributed on each side of the labial groove, a needle-like stylet fascicle comprising two mandibular and two maxillary stylets, a crescentshaped mandibular stylet with several serrate ridges (Sr) on the surface of each stylet tip and one row of numerous tooth-like projections on the lateral edge of each stylet and two maxillary stylets held together forming a food canal (Fc) and a salivary canal (Sc).…”

“…In P. albinotata, on the medial surface of the tip of each mandibular stylet, there is a row of ridges (Sr) giving the stylet a serrate appearance. These structures presumably are specialized for perforating plant tissues using stylet movement and the extent of their development may be related to the depth of stylet penetration into the host plant (Garzo et al, 2012;Leopold et al, 2003;Liang et al, 2013;Rani and Madhavendra, 2005;Zhao et al, 2010). Such ridges are also found in other hemipteran insects, but differ in number and pattern among taxa.…”

“…Each mandibular stylet has five teeth in Delphacidae (Dai et al, 2014) and ten teeth are present in Psyllidae (Garzo et al, 2012;Liang et al, 2013;Pollard, 1970;Ullman and McLean, 1986), whereas more than ten ridges may be found on the mandibles of Aphididae (Forbes, 1969) and nine to twenty teeth occur in different species of leafhoppers (Leopold et al, 2003;Zhao et al, 2010). The teeth are sharper in predacious hemipterans than in phytophagous hemipterans (Anderson et al, 2006;Boyd et al, 2002;Boyd, 2003;Garzo et al, 2012). In P. albinotata, except for five dorsal nodules, numerous ridges on the apical half of the stylet are restricted to the ventral part of the external convex region while the dorsal part is smooth.…”

“…In addition, because mouthpart structures may be characteristic of all members of a genus, family or order of insects, knowledge of mouthpart morphology is useful for classification and identification (Gullan and Cranston, 2005). Previous work on the ultrastructural morphology of Hemiptera mouthparts, using light and scanning electron microscopy, has mainly focused on Heteroptera (Anderson et al, 2006;Boyd, 2003;Cobben, 1978), Aphidoidea (Forbes, 1969;Pollard, 1973;Razaq et al, 2000), Psyllidae (Garzo et al, 2012;Liang et al, 2013) and Aleyrodidae (Rosell et al, 1995;Walker and Gordh, 1989) of Sternorrhyncha, and Cicadellidae (Tavella and Arzone, 1993;Leopold et al, 2003;Wiesenborn, 2004;Zhao et al, 2010;Ammar and Hall, 2012) and Fulgoroidea (Brentassi and de Remes Lenicov, 2007;Dai et al, 2014;Liang, 2005) of Auchenorrhyncha. Apart from some brief notes on the stylets of Philaenus spumarius (L.) (Pollard, 1971) and Notozulia entreriana (Berg) (Paladini et al, 2008), and the interlocking pattern of maxillae and mandibles of Aphrophora alni (Fall en) (Cobben, 1978), fine structure of the mouthparts in spittlebugs has received little attention.…”