Salix Cinerea Research Articles

Survival and relative frequency of native woody species and their specialist Lepidoptera on Coll, Inner Hebrides, two millennia after deforestation

AbstractThe Hebridean island of Coll has almost certainly been predominantly treeless for at least two millennia; it was certainly largely deforested when the first surviving written description of the island was made in the sixteenth century. A survey of the surviving native trees, shrubs and lianes carried out between 1997 and 2011 showed that only Salix aurita is present in any quantity, with all other species being reduced to small, relict stands or scattered individuals. Juniperus communis (at least 650 bushes), Populus tremula (450 trees) and Sorbus aucuparia (121 trees) are the commonest of these species and represent contrasting strategies, with P. tremula present as long-lived suckering clones and the others as freely seeding but probably short-lived individuals. Betula pubescens (42 trees), Hedera helix (50 plants), Corylus avellana (17 trees), Quercus spp. (11 trees) and Salix cinerea (4 stands) are the rarest surviving native species. Historical records indicate a decline since the 1930s of Be...

The prospects for the survival of the population of a boreal relict species, Betula humilis Schrk., in a small isolated peat bog in the Łęczna - Włodawa Lakeland

An attempt was made to identify the major risks to the population of <i>Betula humilis</i> Schrk. existing in a small isolated transitional peat bog near Lake Bikcze, in the Łęczna-Włodawa Lakeland. The biometric features of 40 <i>Betula humilis</i> individuals were measured as well as the growth of shoots, flowering and fruiting were observed. Habitat conditions were characterized by making measurements of selected abiotic and biocenotic environmental factors. The obtained results allowed us to identify two main threats to the proper functioning of the study population. The first one is the possible loss of genetic identity of the species as a result of probable ongoing introgression by the potential crossing of <i>Betula humilis</i> with other species of the genus <i>Betula</i>, which are numerous in the flora of the studied area. Another threat is a change in habitat conditions (mainly light and water conditions), which is due to the accelerated secondary succession manifested by the expansion of common species such as <i>Salix cinerea</i>, <i>Betula pendula</i>, and <i>Phragmites australis</i>.

Occurrence of beetles (Coleoptera) species on broad leaf willowsWystępowanie chrząszczy (Coleoptera) na wierzbach szerokolistnych

Observations on the occurrence of Coleoptera species were made on broad leaf willows (Salix cinerea L. and S. caprea L.) plantation in 2009–2011. The results showed that the species Crepidodera aurata L. (Alticidae), Trachys minuta L. (Buprescidae) and Dalopius marginatus L. (Elateridae) were the most numerous. Apart from C. aurata the other dangerous beetle species to energy willow (S. viminalis) occurred with a very low intensity.

Plant-mediated effects of different Salix species on the performance of the braconid parasitoid Perilitus brevicollis

The blue willow beetle, Phratora vulgatissima, is considered to be the most damaging herbivorous pest in Salix short-rotation coppices throughout Europe. The braconid parasitoid Perilitus brevicollis is an important natural enemy of Phratora. As several different Salix species are used in coppices, I investigated the bottom–up (tritrophic) effects of Salix on the parasitoid. Three host plants were studied: the introduced fast-growing S. viminalis, which is highly susceptible to the beetle; S. dasyclados, which is introduced and moderately-resistant to the beetle; and the native slow-growing Salix cinerea, which is not currently used in coppices. The identity of the host-plant species had significant effects on parasitoid larval development time; parasitoids developed rapidly on the susceptible S. viminalis and slowly on the moderately resistant S. dasyclados. Increased development time resulted in reduced adult longevity. Host-plant species identity also affected larval survival; 57%, 64%, and 49% of the parasitoids successfully completed larval development in beetles fed S. viminalis, S. cinerea, and S. dasyclados, respectively. Parasitoid development was also correlated with the body size of their beetle host, but this effect was independent of the identity of the host-plant species. The results of this study suggest that the parasitoid has higher survival and growth rates when it parasitizes beetles feeding on the common coppice species S. viminalis, but the performance of the parasite is reduced when the beetle feeds on the moderately-resistant S. dasyclados. Conversely, the omnivorous biocontrol agents sometimes used in these systems appear to perform better on S. dasyclados compared to S. viminalis. The results of this study suggest that Perilitus parasitoids and omnivorous beetle predators may provide complementary protection to Salix and therefore be useful in coppice management.

Optimizing invasive species control across space: willow invasion management in the Australian Alps

Summary1. A key problem facing invasive species management is how best to allocate surveillance and control effort. Models of the establishment and spread of invasive species are widely used to predict species’ occurrence across space and inform resource prioritization. However, the way they should be used to direct control effort is less clear. Managers could exhaustively search and treat the few highest priority locations or apply less thorough effort more broadly. The choice between these options is a question of balancing resources to maximize local success while minimizing further spread.2. We link a spatial model predicting the likelihood of occurrence with a decision model to efficiently allocate human resources to control the weed Salix cinerea in south‐eastern Australia. Using data collected during an ongoing control programme, we construct a species distribution model, empirically estimate control effectiveness and perform a budget‐constrained optimization that identifies priority regions for control.3. Two alternative scenarios were explored against two seasonal budgets: control is equally valued in all areas or control is doubly valuable in conservation areas.4. Optimal control effort per site varied according to the likelihood of occurrence and site‐specific benefits of control. Prioritizing conservation areas led to a reduction in area treated because of greater allocation of control effort.5. Quantifying control effectiveness was critical for realistically allocating control effort. Targeting obvious individuals and then moving to new sites was more cost‐effective than attempting to control every individual at a high‐priority site.6. Synthesis and applications. We have developed a method to identify priority locations for invasive species control across a landscape. By integrating a decision model with an empirical distribution model, our method offers a better management outcome by maximizing the efficiency of control efforts. It identifies where and how much control effort should be allocated for maximum effect within a season. Effort is expressed as control staff time spent per site with the allocation readily visualized as a map. In general, a strategy of visiting sites where the species is most likely to occur and exerting a moderate amount of effort at these sites is most efficient.

Patterns of seedling recruitment in experimental gaps on mosaic vegetation of abandoned meadows

The paper presents results of a study on the response of species growing in experimental gaps in the patches dominated by <em>Carex acutiformis</em>, <em>C. cespitosa</em> and <em>Salix cinerea</em>. The study was performed in a meadow area subjected to the process of succession in the Reski Range in the Białowieski National Park. Four patterns of seedlings recruitment in the experimental gaps were distinguished: pattern I - great number of seedlings with high richness of species, pattern II - great number of seedlings with low richness of species, pattern III - low number of seedlings with great richness of species and pattern IV - low number of seedlings with low richness of species.

Short Rotation Forestry (SRF) in a Mediterranean Environment Under Limited Energy Inputs

The aim of this work is comparing the two year performance (diameter, total height and mortality) of twenty tree and shrub species in a semi arid environment. The research also wants to supply recommendation on the agronomic cropping techniques in areas where rainfall is the main limiting factor and water use is strictly limited. Woody biomass is gaining increasing importance for energy production in Italy. During the last five years, roughly 5000 ha of Short Rotation Forestry (SRF) have been planted, mostly in northern Italy, especially using poplar clones. However, in Southern Italy, due to the poor rainfall and the lack of knowledge existing on the species to use, few groves have been established. The studied groves were set in December 2005 in a Mediterranean area where the total year rainfall is not higher than 600 mm (mostly in autumn and winter). Twenty species (Salix cinerea, Ulmus carpinifolia, Corylus avellana, Spartium junceum, Acer saccharinum, Morus alba, Saphora japonica, Eleagnus angustifolia, Fraxinus angustifolia (var oxicarpa), Sambucus nigra, Robinia pseudoacacia, Populus nigra, Albizia julibrissis, Populus alba, Salix alba, Ailanthus altissima, Alnus cordata, Ficus carica, Eucalyptus camaldulensis, Celtis australis) were planted in “collection” plots and set in singular plots on single rows (3 m X 0.5 m spacing). Six species (R. pseudoacacia, P. nigra, P. alba, S. nigra, E. camaldulensis, and A. altissima) were planted in eighteen random “experimental” split-plots, using single and twin rows (0.5 m spacing between plants). Plots had a rectangular plant spacing (3 m between singular and twin rows, 0.5 m on each row). Plant density was roughly 6670 cuttings ha-1 in “collection” plots with singular rows and 10950 cuttings ha-1 in “experimental” plots using single and twin rows. The expected harvest interval ranges from 2 to 5 years, depending on the first results. In the “collection” plots, the first results showed good performances in terms of diameter and total height of R. pseudoacacia, E. camaldulensis and E. angustifolia. The highest mortality percentage was recorded for S. nigra, P. nigra, P. alba both in “collection” and “experimental” plots. All other species showed mortality percentage lower than 20%.

Influence of flooding and metal immobilising soil amendments on availability of metals for willows and earthworms in calcareous dredged sediment-derived soils

Soil amendments previously shown to be effective in reducing metal bioavailability and/or mobility in calcareous metal-polluted soils were tested on a calcareous dredged sediment-derived soil with 26 mg Cd/kg dry soil, 2200 mg Cr/kg dry soil, 220 mg Pb/kg dry soil, and 3000 mg Zn/kg dry soil. The amendments were 5% modified aluminosilicate (AS), 10% w/w lignin, 1% w/w diammonium phosphate (DAP, (NH 4) 2HPO 4), 1% w/w MnO, and 5% w/w CaSO 4. In an additional treatment, the contaminated soil was submerged. Endpoints were metal uptake in Salix cinerea and Lumbricus terrestris, and effect on oxidation–reduction potential (ORP) in submerged soils. Results illustrated that the selected soil amendments were not effective in reducing ecological risk to vegetation or soil inhabiting invertebrates, as metal uptake in willows and earthworms did not significantly decrease following their application. Flooding the polluted soil resulted in metal uptake in S. cinerea comparable with concentrations for an uncontaminated soil.

No effect of larval experience on adult host preferences in Polygonia c‐album (Lepidoptera: Nymphalidae): on the persistence of Hopkins’ host selection principle

Abstract 1. The possible effect of juvenile imprinting or ‘chemical legacy’ on the subsequent oviposition – often called the ‘Hopkins’ host selection principle’– has been a controversial but recurrent theme in the literature on host‐plant preference. While it appears possible in principle, experimental support for the hypothesis is equivocal. The present study points out that it is also important to consider its theoretical implications, and asks under what circumstances, if any, it should be favoured by natural selection.2. Following this reasoning, it is predicted that host preference in the polyphagous butterfly Polygonia c‐album L. (Lepidoptera, Nymphalidae) should not be influenced by larval environment. This was tested by rearing larvae on three natural host plants: the high‐ranked Urtica dioica and the medium‐ranked Salix cinerea and Ribes uva‐crispa, and exposing the naive females to oviposition choices involving the same set of plants.3. It was found that larval host plant had no effect on oviposition decisions of the adult female. Hence, the Hopkins’ host selection principle does not seem to be applicable in this species.4. Based on recent insights on how accuracy of environmental versus genetic information should affect the control of developmental switches, the conditions that could favour the use of juvenile cues in oviposition decisions are discussed. Although the Hopkins’ host selection hypothesis cannot be completely ruled out, we argue that the circumstances required for it to be adaptive are so specific that it should not be invoked as a general hypothesis for host selection in plant‐feeding insects.

Phytosociological and ecological relations in the communities with the share of Carex chordorrhiza L. f. inside and outside the dense geographical species range

The aim of this study was to investigate and evaluate the sociological relations of communities with the share of C. chordorrhiza L. f. in the area inside the dense geographical range (IGR), and to compare the data with records from outside the dense geographical range OGR). We also described the environmental conditions with the use of the phytoindication method, and indicated phytocoenotic factors affecting the protection of the population of this threatened species.String sedge was most frequently noted in the Sphagno-Caricetum rostratae association. The OGR communities contain a smaller number of species, and especially of trees, shrubs and herbaceous plants. Eriophorum vaginatum, Sphagnum capillifolium, Lysimachia vulgaris, Scheuchzeria palustris, Polytrichum strictum, or Straminergon stramineum, i.e., species whose frequency and coverage is high in the IGR communities, were not observed here. The IGR communities are found in relatively poor and highly acidified habitats, whereas the OGR communities occur in various habitats and are more diverse floristically. The present results demonstrate that large threat for C. chordorrhiza is posed by tree and shrub expansion (Betula pubescens, B. pendula and Salix cinerea), which has been reported for many years and is often caused by drainage.

Effect of decomposing litter on the mobility and availability of metals in the soil of a recently created floodplain

Some newly created wetland areas in the Scheldt estuary are heavily contaminated by metals. They are expected to be colonised by reed ( Phragmites australis) and, on a longer term, willow ( Salix ssp.). Supplying litter or stimulating plant biomass production on the short term could be possible management options to restrict metal mobility or availability in the upper soil layer. The influence of litter application on the mobility and availability of metals in the top layer of a soil of a recently created floodplain along the river Scheldt (Schelde) was studied in a greenhouse experiment. Reed stem, reed leaf and willow leaf litter were dried, ground and added to the soil. The treated soil was subsequently subjected to permanently flooded and alternately flooded/drained conditions. Metal concentrations were measured in the pore water, surface water above the soil and percolates. Moreover, reed plants ( P. australis), duckweed ( Lemna minor) and willows ( Salix cinerea) were allowed to grow on these soils. Metal concentrations in the plants, growth and chlorophyll fluorescence were measured. Decomposing litter was found to affect the metal mobility and availability. During the first weeks after litter supply, the concentrations of some metals (e.g. Cd, Cu, Ni and Zn) in the pore water markedly exceeded remediation thresholds for ground water. The metal concentrations started to decrease after some days or weeks, which might be attributed to re-adsorption to different soil phases, a decreasing presence of soluble organometallic complexes and a lowering competition with Ca 2+ for sorption to the solid soil phase. However, most data point towards a role of sulphide precipitation upon sulphate reduction, which is affected by the type of litter supplied to the soil. The used willow leaf material was found to release more sulphates compared to the litter originating from reed plants. When the soils were alternately flooded, metals were exported through the percolates. Total metal export substantially increased when litter was added. Growth and metal concentrations in duckweed, reed plants and willows were affected by the supply of litter, whereas photosynthesis was less affected. The experiments should still be performed on pilot scale before developing wetland management guidelines from these results.

Evaluation of triclopyr triethylamine for the control of wetland weeds

Several experiments evaluating the susceptibility of aquatic and wetland weeds to triclopyr TEA were carried out using potted plants Seedlings of grey willow (Salix cinerea) alder (Alnus glutinosa) and purple loosestrife (Lythrum salicaria) and cuttings of crack willow (S fragilis) primrose willow (Ludwigia peploides) water celery (Apium nodiflorum) water cress (Nasturtium officinale) and monkey musk (Mimulus guttatus) were collected in the field and grown in cultivation At least 2 months after potting up triclopyr TEA was applied to run off at rates between 025 and 5 v/v This resulted in excellent control of all weeds at all rates except for purple loosestrife which was not controlled well at the lowest rate

Leaf trichome responses to herbivory in willows: induction, relaxation and costs

To circumvent the inherent problem of discriminating between the cost of losing photosynthetic tissue and the cost of producing an inducible defence, the growth response of herbivore-damaged plants was compared with plants damaged mechanically to the same extent but without eliciting the defence. Two experiments were conducted, studying the response of willows (Salix cinerea) to damage by adult leaf beetles (Phratora vulgatissima). In the first experiment, willows produced new leaves with an enhanced leaf trichome density 10-20 d after damage, coinciding in time with the feeding of beetle offspring. The response was relaxed in foliage produced 30-40 d after damage. In the second experiment, which also included mechanical damage, willows exposed to beetle feeding showed an increase in leaf trichome density of the same magnitude (> 70%) as in the first experiment. The cost of producing the defence was a 20% reduction in shoot length growth and biomass production. Willows exposed to mechanical damage had an 8% reduction in shoot length growth compared with control plants, that is, a cost of leaf area removal. The results are the first quantitative estimates of the cost of a plant defence induced by natural and low amounts (3.3%) of herbivory.

Uptake of Cd, Zn and Mn by willow increases during terrestrialisation of initially ponded polluted sediments

Metal concentration of plants growing on contaminated soils among other factors may depend on changes in the hydrological regime of the soil. Foliar and stem metal concentrations in Salix cinerea (grey sallow) were measured in 2 consecutive growing seasons on a submerged sediment-derived soil that underwent gradual terrestrialisation. Foliar and stem cutting concentrations for Cd, Zn and Mn increased on plots that were submerged during the first year, but emerged in the second year of monitoring. The litter layer was sampled under the shrubs of a plot with a recent abrupt change in hydrological regime and on the reference plot. It was separated in three size fractions through sieving. Analysis of the litter fractions suggested that Cd and Zn concentrations remained constant during fragmentation. However, Cr, Cu, Ni and Pb concentrations increased, which was attributed to adhesion of mineral soil particles on the fine fraction. After correction for the metal content in the mineral fraction, an increase in Cd, Mn and Cu concentration during fragmentation of the organic part of the litter layer was observed for the polluted plot. Net litter layer decomposition rate was low, which may indicate low colonisation by the decomposing community. Terrestrialisation resulted in higher Cd, Mn and Zn uptake by willows. The deviant litter layer metal concentrations for Cd, Zn and Mn and low decomposition rate must be further monitored. Feasibility of measures aiming at re-establishing wetland conditions for the dredged sediment landfill must be considered.

Grazing and fire in two subalpine peatlands

The floristic composition and structure of peatland vegetation in adjoining subalpine catchments of the Bogong High Plains (north-eastern Victoria) were monitored between 1979 and 2006. Grazing by cattle had been excluded from one catchment since 1946, when it was fenced. Peatland vegetation in both catchments was partially burnt in a wildfire in 2003. Between 1979 and 1999, in the ungrazed peatland, the cover of Sphagnum cristatum Hampe and Baeckea gunniana Schauer increased and the cover of pools decreased, whereas in the grazed peatland the cover of B. gunniana and Epacris paludosa R.Br. decreased and the cover of Empodisma minus (Hook.f.) L.A.S.Johnson & D.F.Cutler increased. The cover of all recorded species decreased following a fire in 2003. Between 2004 and 2006, a significant increase in cover was detected in two of eight species measured in burnt areas. In burnt areas, the number of native species per quadrat increased in the grazed peatland and the numbers of exotic species per quadrat increased in both peatlands over that period. By 2006, the peatlands had largely recovered floristically from the 2003 fires but it is likely to be decades before the cover of S. cristatum and Richea continentis B.L.Burtt. reaches pre-fire levels. Control of several exotic species that established after the fire (especially Salix cinerea L. and Juncus spp.) may be required.

Habitat difference in abundance of willow leaf beetle <I>Phratora vulgatissima</I> (Coleoptera: Chrysomelidae): plant quality or natural enemies?

Herbivorous insects are influenced by both 'bottom-up' forces mediated through host plants and 'top-down' forces from natural enemies. Few studies have tried to evaluate the relative importance of the two forces in determining the abundance of insects. The leaf beetle Phratora vulgatissima Linnaeus sometimes occurs at high densities and severely damages the willow Salix cinerea in forest habitats. For willows growing in open agricultural landscapes (farmland S. cinerea), the leaf beetle generally occurs at low densities and plants receive little damage. The purpose of the present study was to evaluate the relative importance of host plant quality and natural enemies behind the observed difference in P. vulgatissima abundance. Female egg-laying and larval performance (growth and survival) were studied on caged willow branches in the field to investigate if plant quality differs between S. cinerea trees growing in forest and farmland habitats. The survival of eggs exposed to natural enemies was examined to see if predation could explain the low abundance of leaf beetles on farmland willows. The results indicated no difference in plant quality; female egg laying and larval performance did not differ between the forest and the farmland. However, heteropteran predators (true bugs) were more abundant, and the survival of eggs was lower, on plants in the farmland habitat than in the forest habitat. The data suggest that the low abundance of P. vulgatissima on farmland willows could not be explained by a poor quality of plants, but more likely by high predation from heteropterans.

Habitat difference in abundance of willow leaf beetle Phratora vulgatissima (Coleoptera: Chrysomelidae): plant quality or natural enemies?

AbstractHerbivorous insects are influenced by both ‘bottom-up’ forces mediated through host plants and ‘top-down’ forces from natural enemies. Few studies have tried to evaluate the relative importance of the two forces in determining the abundance of insects. The leaf beetle Phratora vulgatissima Linnaeus sometimes occurs at high densities and severely damages the willow Salix cinerea in forest habitats. For willows growing in open agricultural landscapes (farmland S. cinerea), the leaf beetle generally occurs at low densities and plants receive little damage. The purpose of the present study was to evaluate the relative importance of host plant quality and natural enemies behind the observed difference in P. vulgatissima abundance. Female egg-laying and larval performance (growth and survival) were studied on caged willow branches in the field to investigate if plant quality differs between S. cinerea trees growing in forest and farmland habitats. The survival of eggs exposed to natural enemies was examined to see if predation could explain the low abundance of leaf beetles on farmland willows. The results indicated no difference in plant quality; female egg laying and larval performance did not differ between the forest and the farmland. However, heteropteran predators (true bugs) were more abundant, and the survival of eggs was lower, on plants in the farmland habitat than in the forest habitat. The data suggest that the low abundance of P. vulgatissima on farmland willows could not be explained by a poor quality of plants, but more likely by high predation from heteropterans.

Influence of leaf trichome density on the efficiency of two polyphagous insect predators

AbstractPlant characteristics, such as leaf structure or hairiness, are important for the movement and attachment of insects. It has been suggested that increased trichome density on new Salix cinerea L. (Salicaceae) leaves, produced after grazing by the willow leaf beetle Phratora vulgatissima L. (Coleoptera: Chrysomelidae), function as an inducible defence against the beetle and especially its larvae. Here we studied whether and how two of the main natural enemies of P. vulgatissima, viz., Anthocoris nemorum L. (Heteroptera: Anthocoridae) and Ortothylus marginalis L. (Heteroptera: Miridae), were influenced by trichome density on S. cinerea leaves. The effect of trichome density on these two predators was studied on plants with different trichome densities, comparing natural enemy efficiency, measured as number of P. vulgatissima eggs consumed or larvae missing and/or killed. To obtain different trichome densities, cuttings of several different clones of S. cinerea were used. In the experiment using eggs as prey, an increase in trichome density was, in addition, induced through leaf beetle defoliation on half of the plants of each willow clone. Furthermore, a field study was performed to investigate whether trichome density was correlated with natural enemy abundance. The results indicate that neither the efficiency of these two natural enemies in the greenhouse, nor their abundance in the field was influenced by trichome density. A well‐known behavioural difference between the two predator species could probably account for the higher disappearance of larvae after exposure to the more active predator. These findings are relevant for the development of pest management programs, not least because the enemies are polyphagous predators. It is concluded that an induced increase in leaf hairiness in willows in response to leaf beetle grazing could be a plant resistance trait worthy of further study in this system, because no negative effects on the main natural enemies were observed.

Differences in Cd and Zn bioaccumulation for the flood-tolerant Salix cinerea rooting in seasonally flooded contaminated sediments

Several authors suggest that a hydrological regime aiming at wetland creation is a potential management option that favours reducing bioavailability for metal-contaminated sites. The hydrological conditions on a site constitute one of the many factors that may affect the availability of potentially toxic trace metals for uptake by plants. Bioavailability of Cd, Mn and Zn on a contaminated dredged sediment landfill (DSL) with variable duration of submersion was evaluated by measuring metal concentrations in the wetland plant species Salix cinerea in field conditions. Longer submersion periods in the field caused lower Cd and Zn concentrations in the leaves in the first weeks of the growing season. Foliar Cd and Zn concentrations at the end of the growing season were highest on the initially flooded plot that emerged early in the growing season. Foliar Zn concentrations were also high at a sandy-textured oxic plot with low soil metal concentrations. Zn uptake in the leaves was markedly slower than Cd uptake for trees growing on soils with prolonged waterlogging during the growing season, pointing at a different availability. Zn availability was lowest when soil was submerged, but metal transfer from stems and twigs to leaves may mask the lower availability of Cd in submerged soils. Especially for Cd, a transfer effect from one growing season to the next season was observed: oxic conditions at the end of the previous growing season seem to determine at least partly the foliar concentrations for S. cinerea through this metal transfer mechanism. Duration of the submersion period is a key factor for bioavailability inasmuch as initially submerged soils emerging only in the second half of the growing season resulted in elevated Cd and Zn foliar concentrations at that time.

Leaf beetle grazing does not induce willow trichome defence in the coppicing willow Salix viminalis

Abstract 1 Willows are frequently attacked and defoliated by adult leaf beetles (Phratora vulgatissima L.) early in the season and the plants are then attacked again when new larvae emerge. The native willow Salix cinerea has previously been shown to respond to adult grazing by producing new leaves with an increased trichome density. Subsequent larval feeding was reduced on new leaves. This type of induced plant response may reduce insect damage and could potentially be utilized for plant protection in agricultural systems.2 Here, we investigated if the willow species most commonly used for biomass production in short rotation coppice, Salix viminalis, also responds to adult beetle grazing by increasing trichome density. Larval performance and feeding behaviour on plants previously exposed to adult beetles was compared with that on undefoliated control plants in a greenhouse.3 We found an overall decrease in trichome density within all the plants (i.e. trichome density was lower on new leaves compared to that for older basal leaves on S. viminalis). However, leaves of beetle defoliated plants had a higher trichome density compared to control plants. Larval growth and feeding was not affected by this difference between treatments. Larvae appeared to remove trichomes when feeding on S. viminalis, a behaviour that might explain the lack of difference between treatments.