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Williamson's Sapsucker (Sphyrapicus thyroideus (Cassin, 1852)) breeds primarily in managed forests in Canada. Its status as endangered will require reliable information to develop habitat management guidelines. Adults provision nestlings with ants gleaned from tree trunks, so we estimated the preferred nestling diet by comparing nestling fecal sac composition with the ant fauna collected in tree trunk traps. For ants, we determined nest densities and substrates by counts along transects within sapsucker nest areas. Ants made up 98% of >10 000 arthropods identified in Williamson's Sapsucker fecal sacs. Of 11 ant taxa available, Williamson's Sapsucker consumed six, of which two large-bodied ant taxa, carpenter ants of Camponotus subgenus Camponotus and ants of the Formica rufa species group, were preferred. Together these two taxa averaged 80% of the nestling diet by biomass and formed >48% of the nestling diet at every nest examined (n = 89). Preference varied regionally: west of the Okanagan Valley, only the two large-bodied ant taxa already mentioned were preferred, in the Okanagan-Boundary and East Kootenay regions, smaller bodied ants of the genus Lasius were also preferred, although these comprised [less than or equal to] 5% of the nestling diet by biomass. Camponotus (Camponotus) spp. nests were 3.3 times more common in wood than soil, and the F. rufa species group were entirely dependent on dead or decaying wood for nest substrate. Given the dependence of Williamson's Sapsucker on these ants, retention and recruitment of dead and decaying wood should be considered a management priority for Williamson's Sapsucker breeding habitat. Key words: ants, Camponotus, diet, Formicidae, Formica, myrmecophagy, Williamson's Sapsucker. Le pic de Williamson (Sphyrapicus thyroideus (Cassin, 1852)) niche principalement dans les forets amenagees du Canada. Etant donne que cette espece est en voie de disparition, des connaissances fiables sont requises pour etablir des lignes directrices d'amenagement de son habitat. Sachant que les adultes nourrissent les oisillons de fourmis glanees sur les troncs d'arbres, nous avons pu etudier le regime alimentaire des oisillons en comparant le contenu de sacs fecaux d'oisillons aux fourmis recueillies dans des pieges installes sur les troncs. Pour les fourmis, nous avons determine la densite des nids et les substrats par decompte le long de transects positionnes pres des nids de pics. Les fourmis totalisaient 98 % de >10 000 arthropodes identifies dans les sacs fecaux des oisillons. Le pic de Williamson consommait six des 11 taxons de fourmis disponibles, avec une preference pour deux taxons de grosses fourmis, soit des fourmis charpentieres du genre Camponotus sous-genre Camponotus et des fourmis du groupe d'especes Formica rufa. Ces deux taxons totalisaient en moyenne 80 % de la biomasse ingeree par les oisillons et constituaient >48 % de ladiete dechaque nichee de pics etudiee (n = 89). Les preferences variaient selonles regions: al'ouestde lavallee de l'Okanagan, seuls les deux taxons de grosses fourmis mentionnes ci-haut etaient preferes tandis que dans OkanaganBoundary et Kootenay-Est, des fourmis plus petites appartenant au genre Lasius etaient aussi preferees, meme si elles constituaient toujours ≤ 5 % de la biomasse apportee aux oisillons. Les nids de Camponotus sous-genre Camponotus etaient 3,3 fois plus communs dans le bois que dans le sol et ceux du groupe F. rufa etaient toujours construits dans du bois mort ou en decomposition. Etant donne que le pic de Williamson depend de ces fourmis, la retention et le recrutement de bois mort ou en decomposition devraient etre consideres comme des objectifs prioritaires pour l'amenagement de l'habitat de reproduction du pic de Williamson. [Traduit par la Redaction] Mots-cles: fourmis, Camponotus, diete, Formicidae, Formica, myrmecophagie, pic de Williamson., Introduction Most woodpeckers (family Picidae) depend on dead and decaying trees for nest excavation and many forage for invertebrates found in dead and decaying wood. Maintenance of dead and decaying [...]

During outbreaks the mountain pine beetle (Dendroctonus ponderosae Hopkins) kills large lodgepole pine trees (Pinus contorta Dougl. ex Loud.) more frequently than smaller ones. There is, however, considerable variation in the relation of diameter to incidence of attack. In a meta-analysis of published data we found that the relationship was primarily determined by geographic location (elevation, latitude, and longitude). We propose a new tree mortality measure, the probability of death index, defined as the average percentage of mortality for trees >23 cm. The index may improve the precision in predictive modeling of tree mortality, as it provides a biologically relevant measure of mortality, since it only includes trees that contribute to the growth of an epidemic and is not influenced by the number of trees within a diameter class. To be useful to forest managers, it must be possible to predict the index from stand parameters that are easily measured. The usefulness of the index was supported by a meta-analysis, which showed that 53% of the variation in the mortality index was explained by geographic location. Tree density did not explain any additional variation. Future research is needed to evaluate the performance of the probability of death index compared with that of other mortality measures. Durant les epidemies, le dendroctone du pin ponderosa (Dendroctonus ponderosae Hopkins) tue plus souvent les grosses tiges de pin tordu (Pinus contorta Dougl. ex Loud.) que les plus petites. Cependant, la relation entre le diametre et l'incidence des attaques varie enormement. Dans une meta-analyse des donnees publiees, nous avons decouvert que la relation est principalement determinee par la position geographique (altitude, latitude et longitude). Nous proposons une nouvelle mesure de mortalite des arbres : l'indice de probabilite de mortalite, definie comme etant le pourcentage moyen de mortalite des tiges de plus de 23 cm. L'indice peut ameliorer la precision des modeles de prediction de la mortalite des arbres parce qu'il fournit une mesure de la mortalite pertinente du point de vue biologique etant donne qu'il inclut uniquement les arbres qui contribuent a la croissance d'une epidemie et qu'il n'est pas influence par le nombre d'arbres dans une classe de diametre. Pour etre utile aux amenagistes forestiers, l'indice doit pouvoir etre predit a partir de parametres du peuplement qui sont facilement mesurables. L'utilite de l'indice est supportee par une meta-analyse qui montre que 53 % de la variation de l'indice de mortalite est expliquee par la position geographique. La densite des arbres n'explique aucune variation additionnelle. D'autres travaux seront necessaires pour evaluer la performance de l'indice de probabilite de mortalite comparativement a d'autres mesures de la mortalite. [Traduit par la Redaction], Introduction Most bark beetles that attack living trees seem to prefer certain tree sizes (Rudinsky 1962; van Hees and Holsten 1994). During epidemics of the mountain pine beetle (Dendroctonus ponderosae [...]

Abstract: An outbreak of the mountain pine beetle (Dendroctonus ponderosae Hopk.) in central British Columbia, Canada, has reached an unprecedented size and intensity and has been spreading. The 2005 emergence [...]

Abstract: The roots of container-grown and manually planted lodgepole pine, Pinus contorta Dougl. ex Loud. var. latifolia Engelm., are often deformed, potentially impacting their health relative to that of naturally [...]

Leptoglossus occidentalis causes significant damage in conifer seed orchards. Host selection by L. occidentalis is not completely understood. Earlier research has demonstrated a preference for certain clones of Pinus contorta, indicating that L. occidentalis responds to chemical or physical cues., The present study aimed to test whether L. occidentalis shows clonal preference across years, and to examine whether the host cues responsible for this could be identified., Surveys were conducted in a lodgepole pine seed orchard in British Columbia in 2008 and 2009. Clones were ranked based on the proportion of their ramets on which L. occidentalis was observed. Ramets were divided into three classes: (i) preferred clones with seed bugs; (ii) preferred clones without seed bugs; and (iii) nonpreferred clones with zero or very low numbers of seed bugs. From each clone, we measured infrared radiation emitted from cones, cone monoterpenes, cone size and numbers of cones per tree., Clone preference was consistent between 2008 and 2009. Clone preference classes differed significantly in α-pinene and δ-3 carene and limonene., Leptoglossus occidentalis was found more frequently on clones with cones of greater diameter and weight., Infrared radiation did not differ between clone preference classes, indicating that it is not used in host acceptance. [ABSTRACT FROM AUTHOR]

Sanitation harvesting for the removal, processing and killing of spruce beetle in infested trees the year after attack is often only partially effective because a significant percentage of beetles emerge from standing trees in the autumn and drop down to the root collar to hibernate under the bark below the duff line. When trees are harvested, these beetles are left behind in stump root collars. We hypothesized that falling of spruce beetle-infested standing trees, in the second summer (before pre-hibernation emergence of beetles), can increase the window of opportunity for sanitation harvesting and extract more beetles from the forest., Thirty Engelmann spruce that had been successfully infested by spruce beetle on a 2-year life cycle in 1995 were selected at each of two locations in the central interior of British Columbia in 1996. At each site, 10 replicates of three treatments were randomly applied. Ten spruce were felled from 29 May to 10 June (early treatment), 10 were felled on 8 August (late treatment) and the remaining 10 were left standing. In mid- August, a pair of nylon screening emergence traps were attached to all trees to capture any immature adults emerging for hibernation., Emergence traps and underlying phloem were collected in late September to early October and revealed that 48-62% of immature adults emerged for hibernation from standing trees, whereas significantly fewer (7-17%) emerged from felled trees., We conclude that, if sanitation harvesting of 2-year cycle spruce beetle-infested spruce cannot occur until the second winter, pre-harvest felling of these trees in the second year can reduce emergence for hibernation by 69-88% and allow the extraction of more beetles over a longer period. [ABSTRACT FROM AUTHOR]

The mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae), outbreak in British Columbia and Alberta, Canada, currently extends over 18.3 million ha of pine forest. The principal host of the insect is lodgepole pine, Pinus contorta var. latifolia Englemann (Pineaceae) although it is a generalist herbivore on pines. Mountain pine beetles do not typically colonise spruce. However, during the current outbreak, several instances of mountain pine beetle attack on interior hybrid spruce, Picea glauca (Moench) Voss×Picea engelmannii Parry ex. Engelmann (Pinaceae) have been noted in areas where severe lodgepole pine mortality has occurred. Occasionally, beetle reproduction within spruce has been successful. Reproductive behaviours of mountain pine beetles reared from pine and spruce, such as female host acceptance and male joining behaviour, were studied on bolts of pine and spruce in laboratory bioassays. Females more readily accepted spruce host material relative to pine. Females that developed in spruce had higher rates of host acceptance of both pine and spruce host material than females that had developed in pine. We interpret these latter results with caution, however, as inference is partially restricted by sourcing viable insects from one spruce in this study. Implications of these findings to the concepts of host adaptation and population dynamics of this eruptive herbivore are discussed. [ABSTRACT FROM PUBLISHER]