More Fun Than Fun: Beetles Lead Complex Social Lives in Dead Trees (original) (raw)
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Chapter 1 Natural History and Ecologyof Bark Beetles
2015
Bark beetles (Coleoptera: Curculionidae: Scolytinae) are a highly diverse subfamily of weevils that spend most of their life histories within plants. They occur in all regions of the world, and are associated with most major groups of terrestrial plants, almost all plant parts, and a broad array of invertebrate and microbial symbionts. Bark beetles have served as some of the most prominent model systems for studies of chemical ecology, symbiosis, sexual selection, population dynamics, disturbance ecology, and coevolution. Bark beetles play key roles in the structure of natural plant communities and large-scale biomes. They contribute to nutrient cycling, canopy thinning, gap dynamics, biodiversity, soil structure, hydrology, disturbance regimes, and successional pathways. Several species in particular can genuinely be designated “landscape engineers,” in that they exert stand-replacing cross-scale interactions. In addition to their ecological roles, some bark beetles compete with hu...
Evolution and Diversity of Bark and Ambrosia Beetles
We review the morphology, larval feeding habits, reproductive behavior, and social behavior of Scolytinae and Platypodinae. Their morphology and behavior are adaptations to a lifestyle centered on tunneling in wood. Tunnels are easily defended, and dead wood is a relatively long-lasting resource that can support large populations but that is unpredictable in space and time; these features favor the evolution of parental care and more advanced forms of social behavior. Bark and ambrosia beetles are unique among beetles in the extraordinary variety of feeding biologies and mating systems; in particular, regular bigyny has evolved in many lineages, an otherwise unknown animal mating system. Sex role reversal is rare in insects but has evolved repeatedly in bark and ambrosia beetles. Finally, we summarize for the first time diversity patterns of mating systems and feeding biology for the entire Scolytinae world fauna, ca. 6000 species in 247 genera.
The bark beetle Ips typographus (L.) on patches of dead or dying host trees
2007
Some of the authors of this publication are also working on these related projects: OpenMetsä summary of the dissertation; ed. by Markku A. Huttunen and Tomi Rosti ISBN 978-952-458-954-3 (PDF) Sarjan edeltäjä Joensuun yliopiston Luonnontieteellisiä julkaisuja (vuoteen 1999) Predecessor Univ. Joensuu, Publications in Sciences (discontinued 1999) ISSN 1795-7257 (printed); ISSN 1457-2486 (PDF) ISBN 978-952-458-953-6 (printed) Joensuun Yliopistopaino 2007 Eriksson, Miikka The bark beetle Ips typographus (L.) on patches of dead or dying host trees: Estimating the colonization success and the risk of consequential tree deaths.
PloS one, 2015
The increasing demand for biofuels from logging residues require serious attention on the importance of dead wood substrates on clear-cuts for the many forestry-intolerant saproxylic (wood-inhabiting) species. In particular, the emerging harvest of low stumps motivates further study of these substrates. On ten clear-cuts we compared the species richness, abundance and species composition of saproxylic beetles hatching from four to nine year old low stumps, high stumps and logs of Norway spruce. By using emergence traps we collected a total of 2,670 saproxylic beetles among 195 species during the summers of 2006, 2007 and 2009. We found that the species assemblages differed significantly between high stumps and logs all three years. The species assemblages of low stumps, on the other hand, were intermediate to those found in logs and high stumps. There were also significant difference in species richness between the three examined years, and we found significant effect of substrate t...
Standing or downed dead trees — does it matter for saproxylic beetles in temperate oak-rich forest
For conservation of forest biodiversity, dead wood in the form of logs, snags, or cut high stumps is sometimes left or created when forests are harvested. In Scandinavia, such dead wood usually comes from conifers. For forests in temperate regions, few studies have analysed composition and species richness of beetles using dead wood of oaks (Quercus spp). In this study in southern Sweden, I examined the occurrence of saproxylic beetles trapped at lying (logs) and standing (snags) dead wood of European oaks (Quercus robur L. and Quercus petraea (Mattuschka) Liebl.) in 13 oak-rich mixed forests of relatively high conservation value. The assemblage of beetles differed strikingly between the lying and standing dead wood. Traps on lying dead wood, compared to traps on standing dead wood, had more fungivores and fewer primary and secondary wood boring species. Of 94 species tested for individual substrate preferences, 48 showed prevalence for different trap/substrate types. Absolute species richness was significantly higher on logs than snags, but a smaller proportion of the snag substrate or snag beetles may have been sampled. For red-listed beetles, no differences in their species richness were detected among substrates. These results suggest that logs of dead oaks are valuable and that both snags and logs of oak should be retained and, if needed, created in forestry, such that they are continuously available in stands.
Spatio-Temporal Distribution of Bark and Ambrosia Beetles in a Brazilian Tropical Dry Forest
Journal of Insect Science, 2016
Bark and the ambrosia beetles dig into host plants and live most of their lives in concealed tunnels. We assessed beetle community dynamics in tropical dry forest sites in early, intermediate, and late successional stages, evaluating the influence of resource availability and seasonal variations in guild structure. We collected a total of 763 beetles from 23 species, including 14 bark beetle species, and 9 ambrosia beetle species. Local richness of bark and ambrosia beetles was estimated at 31 species. Bark and ambrosia composition was similar over the successional stages gradient, and beta diversity among sites was primarily determined by species turnover, mainly in the bark beetle community. Bark beetle richness and abundance were higher at intermediate stages; availability of wood was the main spatial mechanism. Climate factors were effectively non-seasonal. Ambrosia beetles were not influenced by successional stages, however the increase in wood resulted in increased abundance. We found higher richness at the end of the dry and wet seasons, and abundance increased with air moisture and decreased with higher temperatures and greater rainfall. In summary, bark beetle species accumulation was higher at sites with better wood production, while the needs of fungi (host and air moisture), resulted in a favorable conditions for species accumulation of ambrosia. The overall biological pattern among guilds differed from tropical rain forests, showing patterns similar to dry forest areas.
Forest Ecology and Management, 2021
Wood-living beetles make up a large proportion of forest biodiversity and contribute to important ecosystem services, including decomposition. Beetle communities in managed southern boreal forests are less species rich than in natural and near-natural forest stands. In addition, many beetle species rely primarily on specific tree species. Yet, the associations between individual beetle species, forest management category, and tree species are seldom quantified, even for red-listed beetles. We compiled a beetle capture dataset from flight intercept traps placed on Norway spruce (Picea abies), oak (Quercus sp.), and Eurasian aspen (Populus tremulae) trees in 413 sites in mature managed forest, near-natural forest, and clear-cuts in southeastern Norway. We used joint species distribution models to estimate the strength of associations for 368 saproxylic beetle species (including 20 vulnerable, endangered, or critical red-listed species) for each forest management category and tree species. Tree species on which traps were mounted had the largest effect on beetle communities; oaks had the most highly associated beetle species, including most of the red-listed species, followed by Norway spruce and Eurasian aspen. Most beetle species were more likely to be captured in near-natural than in mature managed forest. Our estimated associations were compatiblefor many specieswith categorical classifications found in several existing databases of saproxylic beetle preferences. These quantitative beetle-habitat associations will improve future analyses that have typically relied on categorical classifications. Our results highlight the need to prioritize conservation of near-natural forests and oak trees in Scandinavia to protect the habitat of many red-listed species in particular. Furthermore, we underline the importance of carefully considering the species of trees on which traps are mounted in order to representatively sample beetle communities in forest stands.
Forest Ecology and Management, 2018
Vertical gradients of habitats are a typical characteristic of forest ecosystems. Sun-exposed dead wood in the upper canopy, for instance, provides a habitat for saproxylic beetles distinct from that in the more shaded dead wood below the canopy. Canopy research, however, is challenging due to both the limited accessibility and potential confounding effects of temperature on trapping probability when activity traps are used. We studied saproxylic beetle assemblages along a complete vertical gradient without bias caused by temperature effects on activity. Using crane-like constructions attached to the top of large Silver Fir trees (Abies alba), we exposed bundles of freshly cut branches of European Beech (Fagus sylvatica), Silver Fir and Norway Spruce (Picea abies) in three different vertical strata (upper canopy, mid-canopy and near the ground). The bundles in the upper canopy were fully exposed to the sun and the bundles in the mid-canopy and near the ground were in the shade. We allowed beetles to colonize the bundles of branches for one growing period and then reared beetles from each bundle over three years. The species composition of saproxylic beetle assemblages differed between bundles in the upper canopy and near the ground; bundles in the mid-canopy had an intermediate assemblage composition. The abundance of saproxylic beetles was higher near the ground than in the upper canopy, whereas the number of species showed the opposite pattern. Overlapping confidence intervals of sample-based rarefaction and extrapolation curves for species diversity indicate that estimated gamma diversity per stratum is similar across the three strata. Our results support earlier studies that revealed the importance of habitat heterogeneity as a driver of the biodiversity of taxa associated with dead wood. As we controlled for wood diameter and tree species diversity, our study suggests that the microclimatic variability within dead woodand thus habitat heterogeneity for saproxylic beetlesis higher in the upper canopy than near the ground. For biodiversity conservation in forests, our results support a strategy of enhancing the number of trees with microhabitats, particularly those with dead branches in the upper tree crown. Dead branches and standing dead trees should only be removed, e.g. for safety reasons, if no other option is available.