Ozone risk and foliar injury on Viburnum lantana L.: A meso-scale epidemiological study Gottardini, Elena; Fabiana CristofoliniauthorResearch and Innovation Centre, Fondazione Edmund Mach (FEM), Via E. Mach 1, 38010 San Michele all'Adige, TN, Italy; Antonella CristoforiauthorResearch and Innovation Centre, Fondazione Edmund Mach (FEM), Via E. Mach 1, 38010 San Michele all'Adige, TN, Italy ...
2015
Journal Article
Host plant shifts by phytophagous insects are often hypothesized as means through which new species could genetically differentiate. For genetic divergence to occur between populations on original ...and novel hosts, the colonizing population must possess genetic variation in performance traits allowing use of and selection by the new host. To test for the existence of genetic variation in Enchenopa treehoppers for the use of novel host plants in the genus Viburnum, we performed a 4-way full sib analysis. Related insects were exposed to 4 different plant species in greenhouse and field settings: the original host plant and 3 novel host species. We estimated genetic variation in performance traits of male and female longevity, and female fecundity and calculated fitness values, nymphal survival, and male and female developmental time to adult eclosion. We found significant genetic variation in traits influencing both survival and reproduction. There were significant interactions between genotype and host, indicating some genotypes are more adept than others at using new hosts. We conclude that sufficient genetic variation exists in this population to facilitate successful shifts to these new hosts.
A new monocyclic C10 iridoid glucoside was isolated from the leaves of Viburnum lantana, together with the two known glucosides, dihydropenstemide and betulalbuside A. The structure of the new ...compound, lantanoside, was established from extensive 1H and 13CNMR, 1D and 2D homo- and heteronuclear correlation experiments.
Specific visible foliar injuries were demonstrated to occur on plants of Viburnum lantana L. (wayfaring tree) when exposed to ozone in open-top chamber experiments. However, although evidence of ...visible injury was reported even for native plants, no comprehensive testing has been carried out under real field conditions. Thus, the extent to which V. lantana may match the requirements to be used as an in situ bioindicator is not fully known. To investigate the actual responsiveness of native V. lantana plants to ozone under field condition, two 1 × 1 km quadrates (named "Margone" and "Lasino"), for which the occurrence of different ozone levels was known, were considered. There, a fully randomized design was adopted to ensure within-quadrate replications and to select V. lantana plants. Measurements confirmed different exposure levels (Margone, Accumulated ozone concentrations Over a Threshold of 40 ppb h (AOT40): 31 952 ppb h; Lasino, AOT40: 23 259 ppb h). Ozone visible foliar symptoms (i) matched the known symptomatology, (ii) were easy to be identified, (iii) confirmed by microscopical validation, and (iv) observed at both quadrates. However, higher frequency of symptoms, earlier date of onset and faster development occurred at the quadrate with the highest ozone exposure (Margone), although not always proportionally with the difference in ozone exposure. This may be partly due to inherent covariation of environmental variables (higher ozone exposure occurred at the sites with higher relative humidity and cooler air temperature, a set of conditions that may promote ozone uptake), and partly due to a set of (unmeasured) other factors that may cause additional oxidative stress to plants. Implications for biomonitoring are discussed.
Larvae and eggs of the leaf beetle Pyrrhalta viburni were investigated for protective devices against predators. The eggs are covered with faeces, which appeared to have no feeding deterrent activity ...against the ant Myrmica sabuleti. Chemical analyses of the material covering the eggs by gas chromatography-mass spectrometry (GC-MS) showed the triterpenes α-amyrin and β-amyrin as main components. Both compounds are also present in the hostplant Viburnum lantana. GC-MS analyses of eggs and larvae showed that 1,8-dihydroxy-3-methylanthraquinone (= chrysophanol) was present in both developmental stages. In the larvae, 1,8-dihydroxy-anthraquinone (= chrysazin) and 1,8,9-trihydroxy-anthracene (dithranol) were also detected. Neither hydroxylated anthraquinones nor dithranol were found in bark and leaf extracts of the hostplant. After assessing the total amounts of these compounds in a single larva, their ecological significance was studied in feeding bioassays with M. sabuleti. Both P. viburni larvae and equivalent amounts of anthraquinones and dithranol deterred feeding by the ants. The role of anthraquinones and triterpenes in P. viburni is discussed.
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