Summary 1.The abundance and performance of the Eastern Spruce Gall Adelgid, Adelges abietis, was evaluated on young, open-grown trees of White Spruce, Picea glauca, whose growth rates had been increased through fertilization or decreased through root-pruning. 2. In general, gall densities were highest on control trees and on mid-crown branches. Reduced galling success on fertilized trees was largely due to higher overwintering mortality of first-generation nymphs. Foliar magnesium, total tannin and total phenol contents were positively, and nitrogen and total monoterpene contents negatively, related to gall density and/or galling success. 3. Although short shoots were more abundant, shoot length was parabolically related to gall density. There was a non-significant parabolic trend between shoot size and galling success and volume. The number and average size of A. abietis females emerging from galls were positively related to gall volume, and realized fecundity was positively correlated to female size. Consequently, fitness was approximately twice as high for nymphs colonizing intermediate-sized than small or large shoots. 4. These results do not support the plant vigour or plant stress hypotheses. The results do, however, agree with predictions of the modified plant stress hypothesis for sucking insects. It is speculated that Adelges abietis lacks the necessary resources for successful gall formation on small shoots and is unable to produce a stimulus large enough to induce gall formation on large shoots. Key-words: Adelges abietis, insect-plant interactions, parabolic plant module size-galler abundance relationship, phenols, tanninsFunctional Ecology (1999) 13, [859][860][861][862][863][864][865][866][867] 859 DeBruyn 1994;Björkman 1997). Studies examining the relationship between insect performance and plant chemistry have also reported varying results (Tija & Houston 1975;Zucker 1982;Waring & Price 1990;Hartley & Lawton 1992;Waring & Cobb 1992;Bryant et al. 1993;Hartley & Jones 1997). Nevertheless, these studies generally found a positive relationship between insect performance and plant nitrogen content, and a negative relationship to secondary compounds (e.g. total phenols, tannins and monoterpenes).This study was carried out to determine the relationship between the abundance and performance of the shoot-galling Eastern Spruce Gall Adelgid Adelges abietis (L.) and the growth rate and foliar chemistry of White Spruce, Picea glauca (Moench) Voss. Tree growth and foliar chemistry were manipulated by fertilization and root pruning. We tested the predictions that gall abundance and galler performance would be higher on fast-growing trees (Plant Vigour hypothesis) with low C/N ratios than on slowgrowing trees with high C/N ratios, as well as the alternative prediction that gall abundance and galler performance would be highest on the slowest-growing, stressed trees (Plant Stress and Modified Plant Stress hypotheses). To obtain an estimate of fitness associated with the colonization of different-sized shoots we ...

Whole cell patch clamping in vivo is an important neuroscience technique that uniquely provides access to both supra-threshold spiking and sub-threshold synaptic events of single neurons in the brain. This article describes how to set up and use the autopatcher, a robot for automatically obtaining high yield and high quality whole cell patch clamp recordings in vivo. Following this protocol, a functional experimental rig for automated whole cell patch clamping can be set up in one week. High quality surgical preparation of mice takes approximately 1 hour, and each autopatching experiment can be carried out over periods lasting several hours. Autopatching should enable in vivo intracellular investigations to be accessible by a significant number of neuroscience labs, and enable labs already doing in vivo patch clamp to scale up their efforts by reducing training time for new lab members and increasing experimental durations by handling mentally intensive tasks automatically.

Delays in budburst in the year following herbivory have previously been attributed to a defensive response to early-season herbivory or localized resource deficiencies (resource availability hypothesis) limiting bud development. We carried out field experiments to test the resource availability hypothesis as well as the crown architecture hypothesis, which attributes changes in the time of budburst in the year following herbivory to changes in the proportion of different bud types. We examined predictions from these hypotheses using a defoliator, Choristoneura fumiferana; a defoliator/stem feeder, Zeiraphera canadensis; and a stem galler, Adelges abietis; on white spruce, Picea glauca. The time of budburst and final leaf size of unexploited midcrown shoots of white spruce were compared to those of adjacent exploited shoots. We also evaluated budburst in a manipulated field study, in which tree growth was reduced through root pruning and increased through fertilization.Partial defoliation by C. fumiferana and Z. canadensis did not affect budburst, but did result in smaller leaves. Almost complete defoliation of shoots by C. fumiferana and galling by A. abietis resulted in delayed budburst. Reductions in leaf size were directly related to the amount of herbivory (i.e., low or high) by C. fumiferana and Z. canadensis. Budburst of trees whose growth rate had been decreased by root pruning or increased by fertilizing occurred later and sooner, respectively, than budburst on unmanipulated trees. The time of budburst was inversely correlated with foliar nitrogen and water content and the length of unexploited shoots. These results supported the resource availability hypothesis. The influence of resource availability on time of budburst was observed at the shoot, branch, and whole-tree levels. When Ͼ50% of stems were destroyed by Z. canadensis, budburst occurred earlier or at the same time in the following spring. This was due to the production of basal buds, which burst before all other buds on a shoot. The production of early-bursting basal buds more than compensated, or just compensated, for a small delay in budburst of terminal, distal-lateral, and medial-lateral buds. Thus, changes in the time of budburst in the year following herbivory were due to changes in crown architecture as well as to changes in resource availability. We predict that increased intra-tree heterogeneity in the time of budburst should make P. glauca more, rather than less, susceptible to two of the herbivores studied because of the presence of a highly nutritious food source, newly burst buds, for a longer period of time. We suggest that the influence of previous herbivory on the time of budburst in the next growing season is a commonly overlooked factor that may have a large influence on herbivore abundance and distribution.

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Intra- and inter-crown distribution of eastern spruce gall adelgid, Adelges abietis (L.) (Homoptera: Adelgidae), on young white spruce, Picea glauca (Moench) Voss., was studied at three sites in New Brunswick, Canada. Within a branch, the majority of galls were found on lateral shoots. Similar distributions of galls within trees were observed regardless of whether 20 or 30 lateral shoots or all shoots on a branch were sampled. Gall densities were highest on mid-crown branches of open-grown trees 1–4 m tall and were not influenced by cardinal direction. After crown closure, most galls were found in the upper crown, above the point of branch overlap. In all circumstances, gall distributions were strongly clumped within trees. Inter-tree distribution of A. abietis galls differed significantly from a Poisson but not a negative binomial distribution, indicating a high degree of aggregation among trees. Therefore, a stratified random sampling plan using 20 lateral shoots of a mid-crown branch as a sampling unit would be adequate for monitoring A. abietis populations. If the mid-crown branches are undergoing crown closure, we suggest sampling in the lowest open-grown branch above the point of crown overlap.