Bionomics and feeding impact ofCtenarytaina eucalypti(Hemiptera: Psylloidea: Aphalaridae) onEucalyptus globulus(Myrtaceae) in the central tablelands of New South Wales

Abstract

Ctenarytaina eucalypti is considered a key pest of Eucalyptus plantations, especially E. globulus, in different parts of the world. In this study different levels of response of E. globulus to oviposition and feeding by C. eucalypti are reported. The responses in the juvenile E. globulus leaf tissues to oviposition include subcellular damage with the accumulation of callosic material superimposed by lignin-like polymers in cells proximal to the oviposition site, indicating the earliest response of stress signals in E. globulus to wounding. The feeding action of the first-and second-nymphal instars on the mesophyll cells inflicts both mechanical and chemical damage and manifests newly developed apoplastic spaces between cell walls and plasma membranes, poorly differentiated primordial-palisade cells, and autolysed protoplast. The phloem-feeding third-, fourth-, and fifth-nymphal instars induce changes in phloem parenchyma, which occur as actively dividing cells and including autophagic vacuoles. Leaf cells fed by adults also include hypertrophied mitochondria, degenerating cytoplasm and secondary metabolic compounds. The arrangement of antennal sensilla of C. eucalypti varies among nymphs and adults. The adults and nymphs of C. eucalypti appear to prefer specific leaf parts, suggesting that the levels and quality of nutrients vary in the same leaf. Growth in C. eucalypti is allometric, and the total body and antennal lengths show similar patterns in growth rates when compared with other sclerotised parts.

Salivary gland structure of Ctenarytaina eucalypti (MASKELL, 1890) (Hemiptera) and phloem exudate in Eucalyptus globulus LABILLARDIÈRE, 1799 (Myrtaceae)

“…Hardened bulbous droplets of the gel-like saliva have been shown in cells encircling the stylet track of C. eucalypti (SHARMA et al 2014). The gel-like saliva is implicated as an avoidance tactic to circumvent allelochemicals of the host plant during feeding (MILES 1999).…”

“…With the introduction of Eucalyptus globulus LABILLARDIÈRE, 1799 and other species of Eucalyptus L'HERITIER, 1789 for commercial reasons, C. eucalypti has spread today as an invasive organism in several regions of the world, such as Italy, Chile, Brazil and Sri Lanka (DE QUEIROZ et al 2012, CABI 2013. Although C. eucalypti's host range includes several species of Eucalyptus, E. globulus appears to be its preferred host (SANTANA & BURCKHARDT 2007, SHARMA et al 2014. Ctenarytaina eucalypti feeds on the juvenile leaves of E. globulus and all developmental stages occur on the same leaf (SHARMA et al 2014).…”

“…Although C. eucalypti's host range includes several species of Eucalyptus, E. globulus appears to be its preferred host (SANTANA & BURCKHARDT 2007, SHARMA et al 2014. Ctenarytaina eucalypti feeds on the juvenile leaves of E. globulus and all developmental stages occur on the same leaf (SHARMA et al 2014). Feeding by C. eucalypti inflicts physiological damage on Eucalyptus (COLLET 2001).…”

“…During feeding, the immatures and adults of C. eucalypti form a proteinaceous sheath around their stylets and the stylet follows an intercellular pathway towards phloem (Figs 1, 2). The feeding action of the early instars inflicts both mechanical and chemical damage and the phloem-feeding late instars and adults induce several signs of degeneration in the leaves of E. globulus (SHARMA et al 2014).…”

Feeding Biology and Nutritional Physiology of Psylloidea(Insecta:Hemiptera):Implications in Host-Plant Relations

“…The stylet length appears to depend on the guild to which the psylloid belongs, although the relationship between the body size and stylet length 32 cannot be overlooked. For example, free-living Ctenarytaina eucalypti (Aphalaridae) bear c. 600 m long stylets, the lerpforming, unnamed species of Glycaspis c. 850 m, and the gall-inducing, unnamed species of Glycaspis (Synglycaspis) c. 950 m (refs [33][34][35] 34,35 ).…”