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Dispersal by flight is obligatory for bark beetles in the subfamily Scolytinae. Adult bark beetles must leave the natal host and fly to seek new hosts for brood production. Because of the eruptive nature of some bark beetle populations, dispersal capacity has implications for beetle spread and invasion across the landscape. Bark beetle dispersal can occur over short distances within a stand or over long distances above the forest canopy, where wind aids dispersal. Despite the obvious importance of dispersal for predicting population spread, knowledge gaps in understanding factors that influence bark beetle dispersal remain. In this review, we synthesize information on bark beetle flight to gain a better understanding of this important life history trait. We assess the impact of genetic, physiological, and morphological traits on flight in different bark beetle species. We also consider the impact of abiotic and biotic environmental conditions on flight. We discuss how measurements of these factors could contribute to the development of comprehensive models to better predict spread of bark beetle populations. Through the synthesis of flight research on a variety of bark beetle species, this review provides suggestions for future avenues of research on this important aspect of bark beetle ecology.Résumé : Le vol est le moyen de dispersion obligatoire chez les scolytes dans la sous-famille des Scolytinae. Les scolytes adultes doivent quitter l'hôte où ils sont nés et s'envoler pour chercher de nouveaux hôtes afin d'assurer leur progéniture. À cause de la nature éruptive de certaines populations de scolytes, la capacité de dispersion a des répercussions sur la propagation et l'invasion de l'insecte dans le paysage. La dispersion des scolytes peut survenir sur de courtes distances à l'intérieur d'un peuplement d'arbres ou sur de longues distances au-dessus du couvert forestier où le vent favorise la dispersion. Malgré l'importance évidente de la dispersion pour prédire la propagation de la population, il y a encore des lacunes dans les connaissances concernant la compréhension des facteurs qui influencent la dispersion des scolytes. Dans cette revue de littérature, nous résumons l'information sur le vol des scolytes pour avoir une meilleure compréhension de cet aspect important du cycle vital. Nous évaluons l'impact des traits génétiques, physiologiques et morphologiques sur le vol chez les différentes espèces de scolytes. Nous discutons de la façon dont la mesure de ces facteurs abiotiques et biotiques pourrait contribuer au développement de modèles complets pour mieux prédire la propagation des populations de scolytes. Par le biais de la synthèse de la recherche sur le vol chez une variété d'espèces de scolytes, cette revue de littérature fournit des suggestions pour de futures avenues de recherche sur cet aspect important de l'écologie des scolytes. [Traduit par la Rédaction]

Pea leaf weevil, Sitona lineatus (L.) (Coleoptera: Curculionidae), can reduce the yield of field pea [Pisum sativum (L.) (Fabales: Fabaceae)] and faba bean [Vicia faba (L.) (Fabales: Fabaceae)]. Adults feed on the foliage and larvae feed on root nodules and nodule-associated Rhizobium Frank (Rhizobiales: Rhizobiacea) bacteria. In this study, we developed a data-based nominal threshold for pea leaf weevil in faba bean. We further tested the efficacy of insecticidal seed treatment and foliar insecticide (thiamethoxam and lambda-cyhalothrin, respectively), and nitrogen amendment for pea leaf weevil control using a multi-year field plot study at two sites in Alberta, Canada. Pea leaf weevil feeding damage significantly reduced faba bean yields. Thiamethoxam reduced adult and larval damage, and protected faba bean yield, while neither lambda-cyhalothrin nor a nitrogen amendment was effective in protecting yield. The percentage of seedlings with feeding on the terminal leaf had a negative relationship with yield and was used to estimate a nominal threshold near 15% of seedlings with terminal leaf damage. Since lambda-cyhalothrin is not effective in managing pea leaf weevil on faba bean, there is a need to research additional integrated pest management strategies to reduce prophylactic insecticidal seed treatments.

The mountain pine beetle Dendroctonus ponderosae Hopkins is a major native pest of Pinus Linnaeus (Pinaceae) in western North America. Host colonization by the mountain pine beetle is associated with an obligatory dispersal phase, during which beetles fly in search of a suitable host. Mountain pine beetles use stored energy from feeding in the natal habitat to power flight before host colonization and brood production. Lipids fuel mountain pine beetle flight, although it is not known whether other energy sources are also used during flight. In the present study, we compare the level of energy substrates, proteins, carbohydrates and lipids of individual mountain pine beetles flown on flight mills with unflown control beetles. We use a colorimetric method to measure the entire metabolite content of each individual beetle. The present study reveals that mountain pine beetles are composed of more protein and lipid than carbohydrate. Both female and male mountain pine beetles use lipids and carbohydrates as energy sources during flight. There is variation between sexes, however, in the energy substrates used for flight. Male mountain pine beetles use protein, in addition to lipids and carbohydrates, to fuel flight, whereas protein content is not different between flown and control females.

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