Insect-induced chemical changes in young lodgepole pine (Pinus contorta): the effect of previous defoliation on oviposition, growth and survival of the pine beauty moth, Panolis flammea

ABSTRACT. 1. Significantly more eggs were laid by adult female pine beauty moths ( Panolis flammea (D&S)) on previously undefoliated lodgepole pine ( Pinus contorta Douglas) saplings than on those which had been partially defoliated the year before.
2. The larval weights, mean relative growth rates and survival rates of P.flammea were lower on defoliated trees than on undefoliated trees.
3. Marked and significant differences between the monoterpene profiles of the shoot cortical oleoresin of defoliated and undefoliated trees were linked to oviposition preferences in P.flammea.
4. Differences occurred between the levels of soluble tannins in previously defoliated and undefoliated trees.
5. The results are discussed in relation to earlier work on insect-induced changes in plants, and the significance of inter-provenance differences in lodgepole pine response is assessed.     

Changing dynamics of the pine beauty moth (Panolis flammea) in Britain: the loss of enemy free space?

1 The pine beauty moth Panolis flammea has two main host plants in Britain: Pinus sylvestris (Scots pine), which is the ancestral food plant where the insect is never abundant enough to cause tree mortality, and Pinus contorta (lodgepole pine), an introduced host tree that has experienced periodic widespread tree mortality due to this pest.
2 We review the recent literature, published mostly after the year 2000, regarding the impact of natural enemies on the population dynamics of P. flammea in Britain.
3 The natural enemies of P. flammea are more diverse and abundant in Scots pine habitat than in lodgepole pine habitat and some of them show differential selection for P. flammea larvae in Scots pine habitat over those located in lodgepole pine habitat.
4 It is concluded that the difference in the population dynamics of this insect in the two different habitats was probably the result of the P. flammea finding enemy-free space in lodgepole pine habitat.
5 Recent evidence on the diversity and impact of natural enemies on lodgepole pine has demonstrated that they currently have a much more significant impact on this pest than they did in the 1970s and 1980s, when outbreaks were frequent.     

Variation in the suitability of Pinus contorta (lodgepole pine) to feeding by three pine defoliators, Panolis flammea, Neodiprion sertifer and Zeiraphera diniana

A series of experiments were carried out on Pinus contorta Dougl. in Scotland to establish if there were any inter-provenance differences in suitability to three major forest pests: the pine beauty moth, Panolis flammea (D and S) (Lep., Noctuidae), the European pine sawfly, Neodiprion sertifer (Geoff.) (Hym., Diprionidae), and the larch bud moth Zeiraphera diniana Guennée (Lep., Tortricidae). There were significant differences in the survival, weight, and development time of P. flammea on different provenances of seedling logepole pine. Southern interior lodgepole pine (ILP) proved to be the most resistant provenance. Larvae performed significantly better on Alaskan lodgepole pine (ALP) and Skeena River lodgepole pine (ELP). Panolis flammea larvae showed significant feeding preference for certain provenances of mature lodgepole pine, with ILP being preferred to ALP, north coastal lodgepole pine, and Scots pine. There were significant differences in the mean relative growth rate of N. sertifer on different provenances of seedling and mature trees. ALP was the most resistant provenance among seedling trees, but the least resistant among mature trees. There were also significant differences in survival on foliage from mature provenances. There were no significant differences in survival of second instar Z. diniana on different provenances of mature lodgepole pine.     

The growth and survival of Panolis flammea larvae in the absence of predators on Scots pine and lodgepole pine

Abstract. 1. The survival, growth and development of larvae of the pine beauty moth, Panolis flammea (D & S) (Lepidoptera: Noctuidae) were examined as part of a study to determine (i) why damaging outbreaks of this insect in Scotland are frequent on lodgepole pine but do not occur on Scots pine, and (ii) why outbreaks are associated with areas of deep un-flushed peat.
2. Larvae were studied inside predator exclusion cages on mature pine trees in Elchies forest where a major infestation occurred in 1978–79.
3. Surprisingly, larval survival was generally greatest on Scots pine and lowest on lodgepole growing in deep peat. Also, larval growth and development were greater on Scots than lodgepole pine and were unaffected by the type of soil in which the lodgepole pine was growing.
4. Larval performance was generally better on lodgepole pine that had been thinned and received fertilizer.
5. Larval survival was affected by pine shoot stage during egg hatch in one of the two years in which this was examined.
6. Observations on P.flammea pupae were confused by disease, parasitism and probably by differences in weight loss caused by differences in larval development. Parasitism by ichneumonid parasitoids was recorded on Scots pine but not on lodgepole pine.
7. It was concluded that (i) the absence of pine beauty moth outbreaks on Scots pine, and (ii) the occurrence of outbreaks on lodgepole pine growing in deep unflushed peat were not the result of lodgepole pine growing in deep peat being a more suitable host plant than lodgepole pine and Scots pine growing elsewhere. It seems more likely that the observed outbreak behaviour of P.flammea in Scotland is associated with differences in predation and parasitism in plantations of difference host plants and in plantations of lodgepole pine growing in different soils.     

Are differences in life history parameters of the pine beauty moth Panolis flammea modified by host plant quality or gender?

Pine beauty moth (Panolis flammea D&S, Lepidoptera: Noctuidae) were reared individually from egg hatch to pupation on one of three host plants, Pinus sylvestris (native host plant), Pinus contorta (Central Interior seed origin – good quality introduced host) and P. contorta (Alaskan seed origin – poor quality introduced host). After emerging from the pupae the adult moths were confined to a Skeena River seed origin of P. contorta. Female pupal weight and adult life span were significantly higher on P. sylvestris than on the two lodgepole pine seed origins. Development time was, however, not significantly different between treatments, but larval mean relative growth rate was found to be negatively correlated with birth weight and positively correlated with pupal weight. The time to emerge from the pupa was also not significantly different between treatments. However, there were marked differences between the genders. Male moths lost a significantly greater proportion of their weight over the pupal stage but lived significantly longer as adults than the females. Female moths emerged from the pupal stage significantly sooner than male moths. There was no apparent advantage of large birth size when looked at in terms of subsequent performance. These results are discussed in light of current life history theory.     

Life span and ovarian dynamics of the pine beauty moth, Panolis flammea (D&S): the effect of low temperatures after adult emergence on reproductive success

Abstract Adult female Panolis flammea were kept at 2^oC either immediately after emergence from the pupae or immediately after mating, for periods ranging from 5 to 20 days and then placed at 15^oC together with a male moth, food supply and suitable oviposition site ( Pinus contorta foliage). Weight loss over the storage period was directly proportional to the time spent at 2^oC irrespective of whether the moths were virgin or mated. Pre-oviposition period decreased significantly from the control after more than 5 days at 2^oC, but there was no significant difference between late mated and early mated moths. The post-storage life span of late mated and early mated moths decreased in proportion to the time spent at 2^oC but late mated moths had significantly longer life spans than early mated moths. Moths mated prior to storage were significantly less fecund than moths mated after storage except those moths kept at 2^oC for 20 days where the fecundities of both treatments were identical (c. 45 eggs/female). These results are discussed in relation to the conditions likely to be experienced by P.flammea in the field and their bearing on the population dynamics of this insect.     

Food-plant effects on larval performance do not translate into differences in fitness between populations of Panolis flammea (Lepidoptera: Noctuidae)

In the UK, Panolis flammea (Denis & Schiffermüller) is a pest of monocultures of non-native lodgepole pine Pinus contorta Douglas, but not of the indigenous host Scots pine P. sylvestrisL. This difference in population dynamics may be due to the adaptation of P. flammea populations to the phenology, chemical composition and natural enemy complement of lodgepole pine. To ascertain if there was local adaptation of P. flammea populations to lodgepole pine, this study tested for improved performance of both larvae and adults on the host plant species from which they were sourced, compared with their performance on the alternative host plant species. No difference was found in the relative mean performance of populations sourced from Scots pine or lodgepole pine plantations, when fed on Scots or lodgepole pine foliage. Larvae grew faster on Scots pine but this difference did not translate into differences in pupal weight, female body weight or fecundity. Indeed, those insects that had fed on lodgepole pine had a longer lifespan than those that had fed on Scots pine, which, if translated into greater probability of mating or higher fecundity, could contribute to the observed outbreak dynamics in the field. The prediction that the observed outbreak dynamics of P. flammea can be explained by the existence of populations locally adapted to lodgepole pine was not supported. These results cast doubt on the use of larval growth parameters as surrogates of fitness in Lepidoptera.     

Effects of nitrate,ammonium and pH on the growth of conifer seedlings and their production of nitrate reductase

Summary Lodgepole pine (Pinus contorta Dougl.), Engelmann spruce (Picea engelmanni Parry), and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were grown in open-ended tube cultures of sand and perlite, irrigated with nitrate, ammonium, and a 1∶1 mixture of ammonium and nitrate, combined factorially with pH values of 4.6, 5.3 and 6.0 giving a total of nine treatments. Douglas-fir showed intolerance to ammonium which was especially marked in root weight. Lodgepole pine and Engelmann spruce made poor growth with nitrate, but showed little difference between ammonium and mixed sources. Only Douglas-fir showed a significant response to pH treatments with pH 5.3 plants being largest. Contamination of the sand with carbonate-bicarbonate, apparently caused seedlings grown in ammonium solutions to be larger in sand than in perlite. Douglas-fir grown in perlite cultures showed a growth response like the first experiment and nitrate reductase activity in the order nitrate > nitrateammonium mixture > ammonium. Plastic bead cultures had poor growth response due to low retention of water by the substrate, but the nitrate reductase assays produced results like the perlite cultures. Lodgepole pine grown in water culture demonstrated the well known pH shift associated with different nitrogen forms, and when assayed for nitrate reductase these seedlings had larger relative activities than Douglas-fir, but the order of activity remained nitrate > mixed source > ammonium.     

Nutrition and growth of coniferous seedlings at varied relative nitrogen addition rate

The growth of two provenances of Pinus sylvestris L. were compared with two provenances of Picea abies (L.) Karst. and with Pinus contorta Dougl. when grown in solution cultures with low nutrient concentrations. Nitrogen was added at different exponentially increasing rates, and the other nutrients were added at a rate high enough to ensure free access of them to the seedlings. During an initial period of the culture (a lag phase), when the internal nutrient status was changing from optimum to the level of the treatment, deficiency symptoms appeared. The needles yellowed and the root/shoot ratio increased. The initial phase was followed by a period of exponential growth and steady-state nutrition. The needles turned green again, and the root/shoot ratio stabilized at a level characteristic of the treatment. These patterns were the same as previously reported for other tree species. The relative growth rate during exponential growth was numerically closely equal to the relative nitrogen addition rate. The maximum relative growth rates were about 6 to 7.5% dry weight increase day^-1. This is a much lower maximum than for broad-leaved species (about 20 to 30% day^-1) under similar growth conditions. The internal nitrogen concentrations of the seedlings and the relative growth rates were stable during the exponential period. Close linear relationships were found between these parameters and the relative addition rate up to maximum growth. During steady state the relative growth rates of the different plant parts were equal. However, there were large differences between genotypes in absolute root growth rate at the same seedling size because of differences in root/shoot ratio. Lodgepole pine had the highest root growth rate, whereas that of Norway spruce, especially the southern provenance, was remarkably low. Yet, Norway spruce had a high ability to utilize available nutrients. In treatments with free nutrient access, growth allocation to the shoot had a high priority in all genotypes, but there was still a marked tendency for luxury uptake of nutrients. Nitrogen productivity (growth rate per unit of nitrogen) was lower than in broadleaved species and highest in lodgepole pine. The relevance of the dynamic factors, i.e. maximum relative growth rate, nutrient uptake rate, nitrogen productivity, growth allocation and root growth rate, are discussed with regard to conifer characteristics and selection value.     

Sub-lethal plant defences: the paradox remains

Lodgepole pine (Pinus contorta) trees of two different seed origins, one a poor quality host (Alaskan lodgepole pine), the other a good quality host (south coastal lodgepole pine), were infested with known numbers of eggs of the pine beauty moth, Panolis flammea. Each tree had paired sleeves, one allowing access by invertebrate predators, the other denying this access. When the sleeves were removed, the numbers of larvae surviving, their weights and developmental stages were assessed. Larvae reared on south coastal lodgepole pine (SLP) in the absence of predators were significantly heavier and had significantly better survival rates than larvae reared in comparable conditions on Alaskan lodgepole pine (ALP). However, in the open sleeves, although the larvae reared on SLP were significantly heavier than those on ALP, survival was significantly greater on ALP. Thus predation was greater on the faster developing larvae on the better quality host. These results indicate that slow growth by a herbivore does not necessarily result in greater vulnerability to predators.     

Successful colonization, reproduction, and new generation emergence in live interior hybrid spruce Picea engelmannii×glauca by mountain pine beetle Dendroctonus ponderosae

1 Although mountain pine beetle Dendroctonus ponderosae Hopkins are able to utilize most available Pinus spp. as hosts, successful colonization and reproduction in other hosts within the Pinaceae is rare.
2 We observed successful reproduction of mountain pine beetle and emergence of new generation adults from interior hybrid spruce Picea engelmannii × glauca and compared a number of parameters related to colonization and reproductive success in spruce with nearby lodgepole pine Pinus contorta infested by mountain pine beetle.
3 The results obtained indicate that reduced competition in spruce allowed mountain pine beetle parents that survived the colonization process to produce more offspring per pair than in more heavily-infested nearby pine.
4 We also conducted an experiment in which 20 spruce and 20 lodgepole pines were baited with the aggregation pheromone of mountain pine beetle. Nineteen pines (95%) and eight spruce (40%) were attacked by mountain pine beetle, with eight (40%) and three (15%) mass-attacked, respectively.
5 Successful attacks on nonhost trees during extreme epidemics may be one mechanism by which host shifts and subsequent speciation events have occurred in Dendroctonus spp. bark beetles.     

Host utilisation by moth and larval survival of pine processionary caterpillar Thaumetopoea pityocampa in relation to food quality in three Pinus species

Abstract 1. The work reported here analysed host utilisation by the pine processionary moth Thaumetopoea pityocampa (Lepidoptera: Thaumetopoeidae), the relationship between moth oviposition patterns and larval performance, the chemical characteristics of the plant in relation to the performance of different larval instars, and the role of these factors in the outbreak capacity of the species. In order to do this, a combination of field and laboratory techniques was used to study three pine species differing in nutritional characteristics.
2. Moths oviposited in the three pine species analysed, although cluster pine received a lower number of batches. Late-instar larvae were able to feed on all three pine species, however first-instar larvae developed on Scots and black pine but died on cluster pine. Consequently, oviposition in cluster pine can be considered an oviposition mistake, and indicates that moths are rather unselective when ovipositing on different pine species.
3. Chemical analysis of needles suggested that the quantity of nitrogen was the main factor responsible for the difference in survival of larvae.
4. The oviposition pattern of the moth and the larval susceptibility to food quality in Thaumetopoea pityocampa agree with the theory that unselective oviposition of the moth is a precondition for eruptive dynamics in phytophagous insects.
5. The success of the larvae depends mainly on the probability of the moth finding a suitable host. This probability is determined strongly by the changes of structure and coverage in Mediterranean pine woodlands, due to human management.     

Tree-rings to climate relationships in nineteen provenances of four black pines sub-species (Pinus nigra Arn.) growing in a common garden from Northwest Tunisia

In the Mediterranean region, the effects of climate change on tree growth have been more and more noticeable in recent decades. Pinus nigra is one of the most common mid-elevation pine in this region and one of the species most affected by increasing dryness. In Tunisia, in order to guide species selection for future reforestation of the Khroumirie Mountains, research studies are under way to improve knowledge of black pine ecology. The effects of interannual climate variations on radial growth were compared for 19 provenances of black pine in a 51-year-old common garden experiment in Souiniet (NW Tunisia, 492m) in a humid Mediterranean bioclimate. A significant positive correlation with April precipitation and a significant negative correlation with spring temperature were noted. A cool wet spring is beneficial to growth as it affects tree water balance at the onset of the growing season; in contrast, spring drought is responsible for low annual growth. Mild January–February temperatures have a positive influence on ring width as mild winters may foster photosynthesis and promote early resumption of cambial activity. Analysis of the pointer years showed that winter snow and hail are major factors limiting growth of black pine in the studied area. Despite overall similarities in ring width to climate relationships among provenances, differences observed attest to the interaction of the environment and genetic control of black pine diameter growth.     

Thidiazuron enhances axillary and adventitious shoot proliferation in juvenile explants of Mediterranean provenances of maritime pine <Emphasis Type="Italic">Pinus pinaster</Emphasis>

The effectiveness of thidiazuron (TDZ) in promoting in vitro organogenesis in cultured embryo axes and cotyledons from two Spanish Mediterranean provenances of Pinus pinaster Aiton is reported. Application of 44.4 μM TDZ as a 6-d pulse on DCR medium and subsequent transference of maritime pine explants to the same medium without growth regulators, but supplemented with activated charcoal, produced between 17 and 19 axillary shoots per embryo axis with no differences between the two provenances. The same sequential treatment allowed adventitious shoot differentiation on 75% of the cotyledons, with a mean of 12.2 shoots regenerated per explant. Axillary and adventitious shoots were rooted ex vitro after an auxin pulse of indole-3-butyric acid and 1-naphthaleneacetic acid. The micropropagation protocols presented here should enable vegetative multiplication of selected families, and elite trees from these Spanish Mediterranean provenances of maritime pine.     

Variation in needle terpenoids among Pinus sylvestris L. (Pinaceae) provenances from Turkey

Variation of terpenes and resin acids in needles of young Scots pine (Pinus sylvestris L.) seedlings from nine different provenances in Turkey was investigated. The provenances represent 1200-km West to East and 400-km South to North transects. Seven monoterpenes and two sesquiterpenes were reported in the needles of pines studied. Generally, the kinds of terpenes were similar but the relative amount of some compounds differed among the origins. The major components of the monoterpene fraction in Turkish sources were α-pinene (84.8%), β-pinene (4.1%) and limonene (3.0%), corresponding to 91.9% of the crude needle extract. In a PCA-analysis, 3-carene, myrcene and terpinolene in seedlings from Turkish provenances were quite low and thus, they were clearly different from a Northern European Scots pine provenance from Finland. In the resin acid fraction, abietic acid (62.4%) and dehydroabietic acid (16.1%) were the most abundant constituents in the needles of the Scots pine from Turkish provenances.     

Local environment prevails over population variations in growth-climate relationships of Pinus pinaster provenances

In view of the projected decrease in precipitation and increase in temperature, a better understanding on growth-climate responses in different populations of tree species is needed to improve and enhance the conservation and management strategies for major forest tree species. In this study, we assessed differences in growth traits (i.e., stem diameter, tree height, and stem radial growth) and analysed climate-growth relationships in five provenances of maritime pine (Pinus pinaster Ait.) grown in four replicated common gardens in Sardinia (Italy). Stem radial growth increased under a positive water balance in late winter and early spring. Conversely, high temperature and low precipitation in summer had a negative impact on stem radial growth. At age 40, none of the considered provenances (Portugal, Corsica, Tuscany, Sardinia-Telti, Sardinia-Limbara) showed a substantial advantage in more than one common garden site for tree height and stem diameter. Nevertheless, differences were found among common garden sites in terms of dendrometric parameters, stem radial growth, and growth-climate responses (including sensitivity to summer drought), suggesting a greater site dependent over tree growth. Although in juvenile stages the Portuguese provenance (in particular) showed greater growth than the Sardinian ones, this study showed that, with tree age, the differences among the five provenances tends to narrow. Therefore, irrespective of the seed source, tree growth patterns and growth-climate responses were similar at age 40. This result can be important for implementing forest management strategies to balance adaptation and mitigation potential of maritime pine plantations in harsh environmental conditions.     

Plasticity of response of tree-ring width of Scots pine provenances to weather extremes in Latvia

Climatic changes and weather extremes are causing shifts in distribution of tree species, affecting productivity of forests. With the northwards advance of deciduous species in Northern Europe, Scots pine (Pinus sylvestris L.) is predicted to decrease survival and productivity. Nevertheless, Scots pine have adapted to diverse environments, hence selection among its populations could be applied to sustain productivity of stands under changing climate. In this study, sensitivity of tree-ring width of Eastern European provenances of Scots pine differing by field performance (Dippoldiswalde, Eibenstock, Rytel, Gustrow, and Kalsnava) to weather extremes in three trials in Latvia (hemiboreal zone) was assessed via pointer year and tolerance analyses. The studied provenances were sensitive to winter temperature regime; the effects of water deficit and vegetation period’s length were also observed, likely due to warming. The sensitivity of tree-ring width to weather extremes, which differed among the provenances indicating plasticity of growth, correlated with field performance. Although transferred north, the top-performing provenances (Gustrow and Rytel) were able to promptly recover after cold spells as well as dry summers and were able to benefit from warm winters and precipitation-rich summers. The bottom-performing provenances (Dippoldiswalde and Eibenstock) were sensitive to cold spells and summer water deficit, yet were unable to benefit from warm winters, nor moist summers. Considering sensitivity and resilience of growth, the studied top-performing provenances, particularly Rytel, showed commercial potential in the hemiboreal region under warming climate.     

Two different strategies for light utilization in photosynthesis in relation to growth and cold acclimation

Seedlings of Lodgepole pine (Pinus contorta L.) and winter wheat (Triticum aestivum L. cv. Monopol) were cold acclimated under controlled conditions to induce frost hardiness. Lodgepole pine responded to cold acclimation by partial inhibition of photosynthesis with an associated partial loss of photosystem II reaction centres, and a reduction in needle chlorophyll content. This was accompanied by a low daily carbon gain, and the development of a high and sustained capacity for non‐photochemical quenching of absorbed light. This sustained dissipation of absorbed light as heat correlated with an increased de‐epoxidation of the xanthophyll cycle pigments forming the quenching forms antheraxanthin and zeaxanthin. In addition, the PsbS protein known to bind chlorophyll and the xanthophyll cycle pigments increased strongly during cold acclimation of pine. In contrast, winter wheat maintained high photosynthetic rates, showed no loss of chlorophyll content per leaf area, and exhibited a high daily carbon gain and a minimal non‐photochemical quenching after cold acclimation. In accordance, cold acclimation of wheat neither increased the de‐epoxidation of the xanthophylls nor the content of the PsbS protein. These different responses of photosynthesis to cold acclimation are correlated with pine, reducing its need for assimilates when entering dormancy associated with termination of primary growth, whereas winter wheat maintains a high need for assimilates as it continues to grow and develop throughout the cold‐acclimation period. It appears that without evolving a sustained ability for controlled dissipation of absorbed light as heat throughout the winter, winter green conifers would not have managed to adapt and establish themselves so successfully in the cold climatic zones of the northern hemisphere.     

Anthropogenic fire and bark thickness in coastal and island pine populations from Alta and Baja California

Aim  Native American fire use influenced bark thickness of coastal and island Monterey pine ( Pinus radiata D. Don) and bishop pine ( Pinus muricata D. Don) populations.
Methods  Basal bark thickness and d.b.h. were measured in two common-garden pine plantations that included all five native Monterey pine populations and nine of 10 native bishop pine populations. One-factor analysis of covariance was used to determine if significant differences in bark thickness existed between island and coastal populations.
Results  Bark thickness was measured on 228 Monterey and 42 bishop pines. Bark thickness in coastal and island Monterey pine populations was significantly different. Bark thickness in coastal and island bishop pine populations was not significantly different.
Main conclusions  Basal bark was thick in populations where there was a history of Native American burning. Basal bark was thin in two island populations where Native Americans have been absent or distant from the pine populations. While other influences no doubt affect the evolution of lower-bole bark thickness, it appears that frequent anthropogenic fires may be a powerful selection force.     

Structure, Production and Leaf Area Dynamics: A Comparison of Lodgepole Pine and Sunflower

Populations of lodgepole pine (Pinus contorta var latifoliaEngelm) and sunflower (Heltanthus annuus L) were examined tocompare the influence of stand density on canopy structure andthe association between canopy structure and the productionof stem volume The plastic responses of canopy structure tocompetitive interactions indicated that the structural dynamicsof lodgepole pine and sunflower populations were similar, thoughthe degree of plastic response differed The influence of canopystructure on the production of stem volume, however, was fundamentallydifferent efficiency decreased as the mean crown size of lodgepolepine populations increased, but this decrease did not occurin sunflower populations This difference was attributed to thelarge accumulation of branch biomass required to display foliageeffectively in the canopies of the perennial lodgepole pine,accumulation which does not occur in the annual sunflower Lodgepole pine, Pinus contorta var latifolia Engelm, sunflower, Helianthus annuus L, leaf area, canopy structure, stand production, carbon allocation