Factors influencing dispersal by flight in bark beetles (Coleoptera: Curculionidae: Scolytinae): from genes to landscapes

Abstract

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]

Landscape-Level And Stand-Level Factors Play Diverse Roles During Different Periods of Dendroctonus Valens Invasion In North China

“…The most effective spatial scale at which bark beetles respond to landscape pattern is primarily driven by their dispersal ability (Jones et al, 2019). Simard et al (2012) found that 500 m was the most effective measure among four landscape scales during the outbreak period of bark beetles, which is different from that obtained from our study (250 m).…”

“…During the incipient stage of an outbreak, weakened or diseased pines are more likely to be selected by bark beetles (Raffa et al, 2008). Once they reach high population levels due to warm climatic conditions and availability of hosts, selective pressure declines as higher densities facilitate successful attack on more vigorous trees (Boone et al, 2011;Jones et al, 2019). In the process of the bark beetle populations from endemic to epidemic, stand-and landscape-level factors can in uence the amount and distribution of tree mortality caused by bark beetles, leading to beetle-killed forest stands across the landscape (Gilbert et al, 2005;Ogris & Jurc, 2010;Raffa et al, 2008;Seidl et al, 2015; Thom et al, 2013).…”

Density‐dependent variability in an eruptive bark beetle and its value in predicting outbreaks

“…Bark beetle behavioral responses to semiochemicals may exhibit plasticity depending on local population densities (Sullivan et al 2011, Klutsch et al 2020), and in the case of mountain pine beetle ( Dendroctonus ponderosae Hopkins), individuals are less deterred by host pine defenses when at high densities (Wallin and Raffa 2004). However, the density dependence of flight‐associated traits has received limited investigation in bark beetles (Sallé et al 2005, Jones et al 2019, Shegelski et al 2019).…”

“…For example, when beetle populations are low, individuals may have to fly longer distances to locate rarer and widely distributed hosts rendered susceptible by microclimate, disease, or localized disturbances (Raffa and Berryman 1980). During such periods, beetles possessing a wing size and wing loading that confers greater flight capacity should be at an advantage (Kausrud et al 2012, Brown et al 2017, Jones et al 2019, Shegelski et al 2019). Likewise, responses to semiochemicals may differ during outbreak and non‐outbreak periods (Miller et al 2005).…”

TRIA-Net: 10 years of collaborative research on turning risk into action for the mountain pine beetle epidemic

“…Movement plays a key role in the spatial dynamics of mountain pine beetle outbreaks. Jones et al (2019) present a thorough review of the main factors determining bark beetle flight and dispersal capacity, a poorly understood component of basic bark beetle biology. Their review provides a summary of the current state of knowledge and identifies key gaps in our understanding.…”