Feeding preferences of the Christmas beetleAnoplognathus chloropyrus(Coleoptera: Scarabaeidae) and four paropsine species (Coleoptera: Chrysomelidae) on selectedEucalyptus grandisclonal foliage

Abstract

Christmas beetles (Coleoptera: Scarabaeidae) (Anoplognathus spp.) and paropsine leaf beetles (Coleoptera: Chrysomelidae) are common defoliators of eucalypts, including several important plantation species, throughout south-eastern Australia. It has already been demonstrated that populations and individuals of several eucalypt species vary in susceptibility to defoliation by these leaf-chewing beetles. The objective of this study was to determine whether significant variation in resistance to insect herbivory was present in Eucalyptus grandis genotypes selected from the hardwood plantation program of State Forests of NSW.Grafted clones from three young trees with significantly less crown damage than neighbouring trees in a plantation established near Byron Bay, NSW, were tested for attractiveness to Anoplognathus chloropyrus adults in a binary choice experiment in the laboratory. Shoots from the resistant grafted ramets were paired with shoots from susceptible seedlings of similar age, and caged with feeding A. chloropyrus adults for 24 h. The Christmas beetles consumed significantly (P ~ 0.05) less leaf area from the resistant shoots, compared to that consumed from the shoots from susceptible seedlings, when given access to both. The binary choice test method was also used to test feeding preferences of four paropsine chrysomelid species: Paropsis atomaria (adults and larvae), P. variolosa (larvae only), Paropsisterna beata (adults), and a Chrysophtharta sp. (adults), using the same E. grandis genotypes. No significant differences (P > 0.05) in feeding preferences were detected for P. variolosa larvae, P. atomaria adults, P. beata adults or the Chrysophtharta sp. adults. In contrast, P. atomaria larvae displayed a significant preference for foliage from the susceptible seedlings. In a larval development study using P. atomaria larvae, those reared on the susceptible foliage developed approximately five days faster and had significantly higher survival than those reared on resistant foliage.Several leaf traits were also compared between the two types of foliage. Leaves of similar age from the resistant clones did not differ significantly from the susceptible seedlings in terms of carbon to nitrogen content or concentrations of the monoterpene, 1,8-cineole. They did, however, have significantly higher specific leaf weight (SLW). SLW may have the potential for use in rapid screening of E. grandis genotypes for susceptibilty to defoliation by leaf-chewing beetles that prefer young soft foliage.

A Review of Perennial Ryegrass Endophytes and Their Potential Use in the Management of African Black Beetle in Perennial Grazing Systems in Australia

“…These include stem-feeders (Abbott, 1993) such as African black beetle (Paine et al, 2011) and common defoliators such as the Christmas beetles ( Anoplognathus spp.) (Johns et al, 2004). It has been suggested that the use of fertilizer with nitrogen (N) in eucalypt plantations could be used as a management option as it has been found to either moderate or negate the effect of severe insect defoliation on growth (Pinkard et al, 2006a).…”

Heritable variation in the foliar secondary metabolite sideroxylonal in Eucalyptus confers cross-resistance to herbivores

“…Sample sizes (the number of trees from each population) are shown next to each bar resistant E. grandis clones were no higher in 1,8-cineole concentration than susceptible clones(Johns et al 2004). Furthermore, experiments manipulating the concentration of both 1,8-cineole and sideroxylonal in leaves have suggested that FPCs have a larger effect on Christmas beetles…”

Description of the Immature Stages and Redescription of the Adults of Ancognatha scarabaeoides Erichson (Coleoptera: Scarabaeidae: Dynastinae), A Member of the Soil White Grub Assemblage in Colombia

“…The feeding preference of L. femoratus adult suggest that this insect may be classified as monophagous, since phytochemical characteristics are common among species of Arecaceae (Asmussen et al 2006;Bjorholm et al 2006). The phenology and physiology of young palms before the reproductive phase is affected by the damage caused by L. femoratus; secondary compounds derived from plants injuries have important effects on herbivores, and in many cases, act as attractants and phago-stimulants (Vallejo et al 1998;Johns et al 2004;Diagne et al 2006).…”