Bark salicylates and condensed tannins reduce vole browsing amongst cultivated dark-leaved willows (Salix myrsinifolia)

Abstract

Vole feeding amongst herbal willows that have a high concentration of salicylates in their bark and leaves, and may therefore be cultivated for use as raw material for herbal medicine was tested in the field and in laboratory conditions. Eight clones of dark-leaved willow (Salix myrsinifolia Salisb.) were cultivated for two years with six different methods combining three fertilisation levels (none, low and high), black plastic mulch applied for suppressing weed competition and unmulched control. Samples for the laboratory feeding trial were taken from the unfertilised plants during willow winter dormancy and twigs were fed to 16 voles as a multi-choice experiment. The bark area removed was calculated from image analysis of the material left by the voles. The diameter and the bark thickness of the twigs were measured. Concentrations of salicin, salicortin, HCH-salicortin, picein, triandrin, triandrin derivative, gallocatechin, (+)-catechin, luteolin-7-glucoside, hyperin, total condensed tannins and total nitrogen were measured from the twigs fed to voles in the laboratory. Browsing by a natural population of voles amongst winter-dormant willows was measured in the field. In the laboratory, voles browsed on 80% of the twigs and in the field voles browsed on 33% of the twigs. Vole feeding followed similar patterns in the field and in the laboratory experiment; feeding was clearly higher amongst the plants grown in unmulched control compared to those in plastic mulch. The same clones, 1, 2 and 6 were preferred in both experiments. Voles preferred thin twigs to thick ones. Feeding correlated negatively with concentrations of salicylates and tannins. As vole feeding seems to be highly affected by willow cultivation method and plant genotype, careful selection of cultivated clones and cultivation methods can enhance the reliability of herbal willow cultivation.

Behavioral archives link the chemistry and clonal structure of trembling aspen to the food choice of North American porcupine

“…Our Wndings echo those of Heiska et al (2007), who reported that vole (Microtus agrestis) feeding seemed to be highly aVected by willow (Salix myrsinifolia) cultivation method and plant genotype. Similarly, Snyder and Linhart (1997) showed that when porcupines fed on phloem of Ponderosa pine (Pinus ponderosa) during winter months, eaten trees diVered biochemically (lower concentrations of the monoterpene limonene) and genetically (allele frequencies at two of nine polymorphic loci) from adjacent trees that had not been fed upon.…”

Moose recruitment in relation to bilberry production and bank vole numbers along a summer temperature gradient in Norway

“…voles) may differ with regard to their tolerance towards feeding deterrents (Halaweish et al 2003;Smith et al 2005), but both groups are negatively affected by high concentrations of protease inhibitors (Nbased defence) and specific phenolic compounds (C-based defence) in their feed (Clarke and Wiseman 2000;Makkar 2003). Accordingly, both moose and voles avoid forage with high concentrations of these metabolites (Sunnerheim-Sjöberg and Hamalainen 1992;Hambäck et al 2002;Stolter et al 2005;Heiska et al 2007). Unfortunately, there are no simple ways of determining the content of defensive compounds in plants (Haukioja 2005).…”

Intrapopulation Genotypic Variation of Foliar Secondary Chemistry during Leaf Senescence and Litter Decomposition in Silver Birch (Betula pendula)

“…Intraspecific genotypic variation in secondary metabolites can be equally substantial as shown for tree species in Betula (Keinänen et al, 1999; Laitinen et al, 2000, 2005), Populus (Schweitzer et al, 2008b), Alnus (Lecerf and Chauvet, 2008), and Salix (Heiska et al, 2007). Genetic variation is a prerequisite for natural selection and evolution, but recent evidence suggests that it can also shape local communities and control ecosystem functioning, especially when found in a dominant plant species (Whitham et al, 2008; Genung et al, 2011; Pastor, 2017).…”