Response Of Beetles Research Articles

Response of bark beetles and woodborers to tornado damage and subsequent salvage logging in northern coniferous forests of Maine, USA

In July 2013, an EF1 tornado and straight line winds caused extensive forest damage in the Scientific Forest Management Area of Baxter State Park in northern Maine, USA. Subsequent salvage operations removed damaged trees from some areas, while leaving blowdown in other areas. Undisturbed control, blowdown, and blowdown + salvage (hereafter, salvage) treatments were established within and adjacent to damaged forests. Bark beetles (Coleoptera: Curculionidae: Scolytinae) and woodborers (Coleoptera: Buprestidae, Cerambycidae; Hymenoptera: Siricidae) were trapped using semiochemical-baited traps from within each of these areas over a three-year period (2014–2016). Disturbance-initiated outbreaks of Dendroctonus rufipennis were a major concern after the windstorm. However, D. rufipennis populations were low throughout the three-year experiment, and were captured more often in controls than in the two disturbed treatments. Overall, bark beetles and woodborers were captured at higher numbers in the two disturbed treatments, relative to controls. Individual species responses varied, with many species found more often in one of the disturbed treatments compared to controls. Species richness and abundance were generally higher in disturbed treatments than in controls. Blowdown and salvage treatments were also more similar to one another than to controls. Large amounts of dead wood provided easily exploitable habitat for wood-inhabiting insects in treatments; however, no evidence of alarming population increases of primary bark beetles were observed, suggesting that salvage operations are not always necessary to protect residual trees from attack by damaging bark beetles.

Behavioural responses of the small hive beetle to volatile components of fermenting honeybee hive products

AbstractThe small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), is a significant pest of managed honeybees in the USA and eastern Australia. The beetle damages hives by feeding on hive products and leaving behind fermented wastes. The beetle is consistently associated with the yeast Kodamaea ohmeri (Etchells & Bell) Yamada et al. (Saccharomycetales: Metschnikowiaceae), and this yeast is the presumed agent of the fermentation. Previous work has noted that the small hive beetle is attracted to volatiles from hive products and those of the yeast K. ohmeri. In this study, we investigated how the volatile compounds from the fermenting hive products change depending upon the source of the hive material and also how these volatiles change through time. We used gas chromatography–mass spectrometry and choice‐test behavioural assays to investigate these changes using products sampled from apiaries across the established range of the beetle in eastern Australia. The starting hive products significantly affected the volatile composition of fermenting hive products, and this composition varied throughout time. We found 61.7% dissimilarity between attractive and non‐attractive fermenting hive products, and identified individual compounds that characterise each of these groups. Eleven of these individual compounds were then assessed for attractiveness, as well as testing a synthetic blend in the laboratory. In the laboratory bioassay, 82.1 ± 0.02% of beetles were trapped in blend traps. These results have strong implications for the development of an out‐of‐hive attractant trap to assist in the management of this invasive pest.

Responses of boreal ground beetles (Coleoptera, Carabidae) to different logging regimes during ten years of secondary succession

Many biological responses may develop over long periods of time, and annual community variation should therefore be controlled in ecological research. We sampled carabid beetles over ten years in Norway spruce dominated forests in Southern Finland, harvested using replicated logging treatments of different intensities. We collected carabids in 1995 (prior to logging) and during four post-harvest seasons, 1996-98 and in 2006. The treatments were clear-cutting (no retained trees), modified clear-cutting (retention of three groups of 20-30 trees within one-hectare core) and gap cutting (three 0.16-ha openings within a one-hectare core), and control (mature unharvested forest). Carabids showed remarkable annual and regional variation at assemblage, ecological-group and species levels, such that was independent of treatments. The total species richness, and that of open-habitat carabids, were higher in cleared sites of all treatments than in control stands in 1997-1998 but not in 2006, suggesting that the logging response was ephemeral by many species. The abundances of forest and generalist carabids were little affected by logging. Open-habitat carabids were more abundant in clear-cuts and modified clear-cuts than in gap cuts, which was still detectable in 2006, suggesting a long-term effect. Open-habitat carabids were less abundant in retention sites of modified clear-cuts and gap cuts than in cleared sites, suggesting that retention attenuates assemblage change. Carabid assemblages of logged stands did not differ from control stands in 1996 but they did in 1997-1998, suggesting a one-year delay in logging response. Carabids showed remarkable annual and regional variation at assemblage, ecological-group and species levels, such that was independent of treatments. The total species richness, and that of open-habitat carabids, were higher in cleared sites of all treatments than in control stands in 1997-1998 but not in 2006, suggesting that the logging response was ephemeral by many species. The abundances of forest and generalist carabids were little affected by logging. Open-habitat carabids were more abundant in clear-cuts and modified clear-cuts than in gap cuts, which was still detectable in 2006, suggesting a long-term effect. Open-habitat carabids were less abundant in retention sites of modified clear-cuts and gap cuts than in cleared sites, suggesting that retention attenuates assemblage change. Carabid assemblages of logged stands did not differ from control stands in 1996 but they did in 1997-1998, suggesting a one-year delay in logging response. In 2006, logged and control stands hosted relatively similar assemblages which, together with the above results, suggests a partial faunal recovery. We conclude that even modest retention provides long-term support for forest carabids, but also that their full assemblage recovery takes longer than 10 years.

Early responses of bark and wood boring beetles to an outbreak of the hemlock looper Lambdina fiscellaria (Guenée) (Lepidoptera: Geometridae) in a boreal balsam fir forest of North America

AbstractWe investigated the early responses of bark and wood boring beetles to an extensive supply of balsam fir (Abies balsamea) trees, stressed or recently killed during an outbreak of the hemlock looper (Lambdina fiscellaria) in Quebec, Canada. The present study aimed to (i) examine beetle assemblages across all levels of defoliation and (ii) assess the relative influences of defoliation, tree mortality, stand structure and spatial context on beetle assemblages. We used three types of traps in each of 36 plots: multidirectional flight interception traps measured adult beetle flight activity within stands, trunk window traps measured visitation rates at trees and emergence traps measured beetle colonization of trees. Flight traps in nondefoliated plots allowed characterization of ‘pre‐outbreak’ beetle assemblages, which were not discernable in emergence traps because few insects colonize heathy trees. ‘Pre‐outbreak’ assemblages, characterized by a mix of polyphagous beetle species (e.g. Evodinus monticola, Dryocoetes autographus), shifted to those dominated by Trypodendron lineatum after extensive defoliation. Two Pissodes species colonized heavily defoliated trees but not dead ones. Defoliation level, conifer basal area, basal area of dead balsam firs and the extent of recently logged areas around sampling plots were positively correlated with the abundance of T. lineatum.

Effects of sublethal phosphine exposure on respiration rate and dispersal propensity of adult females of Tribolium castaneum

An understanding of how sublethal exposure to phosphine affects an organism’s respiration is important for predicting its effects on activities depending on a reliable energy source including movement. After treatment with the appropriate sublethal doses of phosphine (LC10), both resistant and susceptible Tribolium castaneum beetles suffered reductions in respiration rates, flight initiation rates and successful location (by walking) of aggregation pheromone lures. The susceptible beetles showed a significantly greater reduction in their respiration rate (53.5%) after exposure to sublethal doses of phosphine compared to the resistant beetles (37.5%), although the respiration rate was still higher in susceptible beetles than in resistant ones. Simultaneously, much larger decreases in the activities associated with both walking and flight were observed in the susceptible beetles, after exposure to sublethal doses of phosphine, compared to the decreases recorded in resistant beetles. The relatively greater reduction in the locomotory responses of susceptible beetles showed that these insects may withstand exposure to phosphine by remaining relatively still and reducing their respiration rate. They would thus minimize their exposure to phosphine, but perhaps only incidentally because the lack of movement may be the result of impairment. By contrast, phosphine-resistant beetles, when exposed to phosphine fumigation, continue to move and may even remove themselves from areas of phosphine exposure. An understanding of how the survivors of sublethal exposures behave is important for predicting the spread and local build-up of phosphine resistance genes and thus improving the control and resistance management of stored grain pests.

Epiedaphic Ground Beetle (Carabidae) Diversity in Ecosystems Transformed by Plantations of Eucalyptus pellita in the Orinoco Region of Colombia.

Patterns of land use are changing dramatically in the Orinoco region of Colombia, including extensive commercial forestation of Pinus caribaea, Acacia mangium, and Eucalyptus pellita that are replacing savannas, with unknown consequences for biodiversity. We studied the effects of E. pellita plantations on the diversity of epiedaphic carabid beetles (Carabidae) sampled with pitfall traps at El Vita (Vichada) and Villanueva (Casanare). Furthermore, we assessed stand structure data (basal area, and canopy cover), and soil physical and chemical properties to explain differences in ground beetle composition using redundancy analysis (RDA). We compared diversity and species turnover using Hill numbers and Bray-Curtis dissimilarity, respectively. Low differences in richness were observed between savannas and plantations (at El Vita) and between pastures and plantations (at Villanueva). In general, carabid richness was significantly (not overlap in 95% confidence intervals) higher during the rainy season, and in young plantations than in other habitats. Variation in carabid species composition was mainly explained by a gradient of volumetric humidity, number of trees, basal area at El Vita and pH, nitrogen content of the soil, number of trees, soil clay content, and area of exposed ground at Villanueva. Thirteen carabid (which eight are commons in natural forests) species were identified as indicators of 3- and 14-year-old E. pellita plantations and pastures. Results suggest a strong response of ground beetles (Carabidae) to changes in land use, seasonality, and plantation age. Further research is needed to better understand how landscape heterogeneity, and distance to contiguous of natural habitats, influences biodiversity.

Dung beetle responses to successional stages in the Amazon rainforest

Amazon rainforest is facing several threats due to anthropogenic activities causing loss of habitat, species, and ecosystem functions. However, several areas are being abandoned after anthropic use allowing secondary succession to occur, which can lead to the passive restoration of community parameters that have been lost. We aimed to investigate the effects of vegetation structure on dung beetle assemblages along a successional gradient in the western Amazon rainforest. Dung beetles were sampled and forest structure variables were measured using standardized protocols along primary, late secondary, and early secondary forests. We used a combination of generalized linear models and multivariate analyses to test for differences in assemblage composition and structure among successional stages and their relationships with vegetation variables. We found that primary forests have different species compositions from both late and early successional forests, with several species strongly associated with primary forests. Dung beetle abundance was higher in primary forests and influenced by variables describing the successional stages (i.e., tree density). Species turnover was the most important β-diversity component among and within each successional stage, with lower values in early secondary forests. Different pathways followed by secondary forests during forest succession may lead to increased species turnover similar to that found in primary forests. Biodiversity conservation will only work if secondary forests are allowed to recover to a late successional stage close to a primary forest stage. The loss of primary forests can cause an irreversible loss of species in need of conservation and with great functional importance in the Amazon rainforest.

Short-term effects of selection, gap, patch and clear cutting on the beetle fauna in boreal spruce-dominated forests

Even-aged management based on clear cutting has simplified the structure of boreal forests, which has adversely affected ecosystem services, including biodiversity. A potential way of combining economic, ecological and social sustainability in forest management is emulation of natural disturbance dynamics. However, ecological effects of alternative cutting methods have been little studied in northern Europe. We studied the responses of beetles (Coleoptera) to four cutting treatments – selection, gap, patch and clear cutting – compared to uncut control stands. We collected beetles one year before, and one and three years after cutting using flight-intercept window traps to assess the effects of treatment, proportion of removed trees, size of harvested gaps, and the volume of dead wood on the species richness and composition of beetles. The total number of species increased sharply in the first year after cutting in all the four treatments. Three years after cutting, the difference in species richness between controls and treatments had decreased. Both species richness and community structure formed a continuum according to treatment intensity. Selection cuts were most similar to the controls, while clear cuts differed from all the other treatments. Irrespective of the treatment, species richness of saproxylic beetles increased with the volume of dead wood, while the number of non-saproxylic species increased with gap size. Contrary to expectation, the proportion of species that were found both before and after cutting did not differ significantly between the treatments. According to an indicator species analysis, two species were associated with controls, 11 with a combination of controls and selection, gap or patch cuts, 17 with patch and clear cuts, and 38 with clear cuts. Our findings suggest that increasing harvesting intensity rapidly increases the total species richness of beetles in the studied spruce forests, but that community recovery may be faster in the less intensive treatments. In the short term, most beetle species inhabiting mature managed forests seem to tolerate cutting disturbances creating open conditions. Clear cuts hosted a large number of species, including species of conservation concern, which were missing from other cutting treatments. Even a moderate increase in the level of dead wood in managed forests is likely to enhance saproxylic diversity. If the aim of management is to preserve mature-forest beetle communities, selection or gap cutting should be used instead of clear cutting.

Energy storage, body size and immune response of herbivore beetles at two different elevations in Costa Rica

The physiological condition and immune responses of organisms living at different elevations are expected to display local adaptations to the different climatic and biotic conditions. Small ectotherms with specialized diets are highly susceptible to environmental change, as their life cycle is largely affected by temperature and by the presence of specific resources. This study focuses on two species of rolled-leaf beetles (Chrysomelidae), both present at two different elevations in Costa Rica: Cephaloleia belti Baly, a diet-generalist, and Chelobasis bicolor Gray, a diet-specialist. Body size, energetic condition (lipid storage), muscle mass and immune condition (melanization response) were compared in beetle populations from a tropical rainforest (50 m elevation) and a tropical montane forest (2 000 m elevation). These measurements reflect current and past nutritional condition and hence are good estimators of individual fitness. We analyzed a total of 172 individuals from both species, sexes and elevations. We predicted that beetles at higher elevation would display larger body size, higher energetic condition and lower immune response associated with metabolic requirements and parasitic pressure in colder temperatures. In general, beetles at high altitude were larger, had more lipids and muscle and showed stronger melanization (i.e., immune response) than beetles at low altitudes. Such differences among populations at different elevations may reflect local adaptation to altitude or phenotypic plasticity. However, the effect of elevation was not equivalent amongst species or sex. Measuring physiological traits in organisms with broad elevational distributions could be useful in understanding possible species responses to climate change.

Beetle ecological indicators – A comparison of cost vs reward to understand functional changes in response to restoration actions

• Reduced grazing affects abundance-, richness- and biomass-based ecological indicators differently. • Richness and abundance indicators are less informative than biomass-based ones. • Family-based functional groups are useful ecological indicators for functional change. • Abundance- and biomass-based indicators offer different functional insights. • Abundance indicators of the most common family groups are the most cost-effective indicators. Ecosystem restoration can play a vital role in conserving biodiversity, but its effectiveness can be difficult to assess for hyperdiverse biota such as insects. Species traits of insects can be used to understand their functional responses to restoration, but their use often requires considerable effort, and few studies have examined what additional insight can be gained from this approach. We used a spatially and temporally controlled restoration experiment to examine beetle species, grouped by flight ability, family membership and feeding guild, as indicators of ecosystem functional change. We tested for the effects of reduced vertebrate grazing on beetle assemblages sampled from two different microhabitats (next to log and in open ground) one year prior and two years after a vertebrate grazing treatment was applied. We compared the responses of the different beetle functional groupings, and then related these to the effort involved in employing these indicators. We found that beetle species traits gave several functional insights into their responses to reduced grazing, including responses to changes in vegetation structure and biomass. Species richness indicators and abundance indicators of beetle functional groups showed similar responses in many cases, whereas biomass indicators gave additional insights related to the extra biomass of vegetation and detritus resulting from the reduction in grazing. We found that most results were revealed by using family groups as indicators for functional change. This is because the traits that often define beetle families, such as size, flight ability and feeding guilds each have distinctive functional roles, allowing a link from family to function, and supporting the idea that phylogeny is often a useful shortcut to species ecology. We conclude that in our study system, the least-cost approach to identifying functional responses of beetles to reduced vertebrate grazing, and possibly other restoration actions, is to use abundance indicators of the most common family groups.

Resilience to disturbance is a cross‐scale phenomenon offering a solution to the disturbance paradox

AbstractResilience is the ability of an ecosystem to return to a previous state following disturbance. Ecological communities may demonstrate resilience after long periods of time. However, short‐term outcomes of disturbance may be reduced functionality despite an increase in biodiversity, a phenomenon known as the disturbance paradox. Silvicultural management regimes are ecological disturbances that vary with the frequency of tree harvests, the age of the tree when harvested, spatial arrangement of harvest, and the area of forest removed. Therefore, they are expected to result in different levels of resilience among forest communities over time. We used the response of temperate hardwood forest beetle communities to different timber harvest treatments in a long‐term research study to test predictions of ecosystem resilience. We also aimed to determine whether this system shows evidence of the disturbance paradox. We predicted that (1) communities following harvest differ from pre‐harvest communities, (2) areas treated with even‐aged management and uneven‐aged management would show community trajectories back to pre‐harvest communities, (3) the more concentrated disturbance of the even‐aged management would lead to a lower community resilience, and (4) community change would be attributed to an increase in pest species using recently harvested wood. The communities did change after timber harvests, but while the dissimilarity between pre‐ and post‐treatment communities was the same for the two treatments, the departure and return to the pre‐harvest community state were along different community trajectories. Furthermore, communities in both treatments showed similar resilience by returning to pre‐harvest community composition at the same rate. As predicted, the abundance of species most responsible for post‐harvest community shifts were those that feed on living wood. This, along with a decrease in abundance of decaying wood decomposers, indicated that the disturbance paradox was playing out in this system.

Long-term experimental management in Swedish mixed oak-rich forests has a positive effect on saproxylic beetles after 10\xa0years

Secondary succession in protected oak-rich temperate forests reduces variation in habitats and leads to denser, shadier sites. Long-term experimental studies of the effects of conservation management alternatives are needed for such forests. Here we present a rare follow-up study of the response of beetles (a highly diverse taxon with many red listed species) to conservation thinning, an action that could favour biodiversity. We previously harvested about 25% of the tree and shrub basal area in a treatment plot, and no trees and shrubs in a nearby matched minimal intervention plot, in each of eight oak-rich (Quercus robur and/or petrea) forest reserves. After two seasons, thinning had led to an increased number of species of both herbivorous and saproxylic beetles. In the present study, we examined the 10-year response of the beetle groups at the same sites. For herbivorous beetles, the initial positive effect of thinning on the number of species had disappeared after 10 years, presumably because of regrowth. In contrast, saproxylic beetles showed a further positive response after 10 years, increasing in the number of species by a third compared to before thinning. We found no change in species composition of either group due to the thinning, but many saproxylics were unique to thinning plots. Overall, our results suggest that in mixed oak-rich forests, saproxylic beetles seem to benefit from conservation-oriented thinning for at least 10 years.

Successional and seasonal changes of leaf beetles and their indicator value in a fragmented low thorn forest of northeastern Mexico (Coleoptera, Chrysomelidae).

Leaf beetles (Chrysomelidae: Coleoptera) constitute a highly diverse family of phytophagous insects with high ecological relevance, due to their host plant specificity and their close association to vegetation variables. Therefore, secondary succession and seasonal changes after loss of vegetal cover will have a significant influence on their community patterns. Accordingly, responses of leaf beetles to such environmental heterogeneity make them a suitable taxon for monitoring disturbance, which is more important for endangered habitats such as the low thorn forests (LTF) in northeastern Mexico. We conducted a study in a LTF fragment in order to assess the effects of secondary succession and seasonality on leaf beetle communities, as well as to quantify the importance of Chrysomelidae as an indicator taxon. Landsat scenes were used for delimiting a successional gradient, in which four succession categories were selected: four years, 17 years, and 31 years since loss of vegetal cover, and conserved areas. Eight plots of 100 m2 were randomly delimited in each category; plots were sampled monthly, using an entomological sweep net, from May 2016 to April 2017. In total, 384 samples were collected by the end of study, from which 6978 specimens, six subfamilies, 57 genera, and 85 species were obtained. Species richness was higher in early succession areas. Abundance declined significantly from early successional to conserved areas, but the conserved areas had the higher diversity. Furthermore, differences in abundance were significant between rainy and dry seasons in areas of four, 17, and 31 years of succession, but not in conserved areas; also, all categories had a similar abundance during the dry season. Intermediate (17 and 31 years) and conserved areas differed in the season of higher diversity. Regarding inventory completeness, it was close to or above 70 % for all comparisons, although it was very low for the 17-year category during the rainy season. Faunistic similarity was higher between intermediate categories. A total of 24 species had a significant indicator value. Effects of succession time and seasonality on leaf beetle communities are here quantified for first time in LTF forests. Influences of environmental heterogeneity and intermediate disturbance are discussed as main drivers of the results obtained. Several leaf beetle species are proposed that could be useful for monitoring succession time and secondary LTF vegetation in northeastern Mexico. However, studies must be replicated at other regions, in order to obtain a better characterization of disturbance influence on leaf beetles.

Behavioral response of the small hive beetle, Aethina tumida (Coleoptera: Nitidulidae) to volatiles of Apicure®, a plant-based extract

Background: The small hive beetle (SHB), Aethina tumida is an invasive pest of the honey bee. Although no previous methods have led to its successful management, yeast inoculated pollen baited-traps have showed promise as quick monitoring tools. In this study, we evaluated the role of olfaction in SHB response to Apicure®, an essential oil-based biopesticide that has shown potential for the management of honey bee pests and diseases. Methods: Volatiles from Apicure® were collected using super Q adsorbent traps. Subsequent analysis was done using Gas chromatography- mass spectrophotometry (GC-MS) to ascertain the components of Apicure®. The selectivity and sensitivity of antennal receptors of A. tumida adults to the volatile compounds were determined using behavioral assays and Gas Chromatography-Electroantennodetection (GC-EAD). Results: GC-MS analysis showed that Apicure® consists of 40 compounds. GC-EAD analysis isolated 11 compounds that elicited antennal response with the SHB. Of these, linalool, camphor, geraniol and α-terpineol were confirmed to be strongly repellant, while limonene was attractive to SHB in dual-choice olfactometer assays. Conclusion: Our results demonstrate that the major components in Apicure® are mainly repellants thus prospective in disrupting the host recognition by the SHB. The product therefore can be up-scaled for the management of SHB.

The response of cerambycid beetles (Coleoptera: Cerambycidae) to long‐term fire frequency regimes in subtropical eucalypt forest

AbstractFire has a varied influence on plant and animal species through direct (e.g. fire‐induced mortality) and indirect (e.g. modification of habitat) effects. Our understanding of the influence of fire regime on invertebrates and their response to fire‐induced modifications to habitat is poor. We aimed to determine the response of a beetle family (Coleoptera: Cerambycidae) to varying fire treatments and hypothesised that the abundance of cerambycid beetles is influenced by fire frequency due to modifications in habitat associated with the fire treatments. Arthropods were sampled across 3 months in annually and triennially burnt areas (treatments starting in 1952 and 1973 respectively), an area unburnt since 1946, and a former unburnt treatment, burnt by wildfire in 2006. Eleven different cerambycid taxa were collected using flight intercept panel traps, dominated by three species (Ipomoria tillides, Adrium sp. and Bethelium signiferum) which made up 99% of individuals collected. Over the sampling period the long unburnt treatment had significantly lower species richness than the triennial and wildfire treatments. Cerambycid abundance was significantly higher in the triennially burnt treatment than in all other fire treatments. Ipomoria tillides was more abundant in both frequently burnt treatments, Adrium sp. was more common in triennially burnt areas, whereas B. signiferum, was more common in the wildfire affected treatment. Some, but not all, cerambycid beetles were more common in areas with a more open understorey (i.e. resulting from frequent burning), and lower tree basal area, as this likely influences their ability to fly easily between food sources. Cerambycid abundance was positively related to the volume of coarse woody debris and healthy tree crowns. Cerambycid beetles were clearly influenced by historic fire regime, suggesting that changes in fire regime can potentially have a profound influence on arthropod assemblages, and subsequent influences on ecosystem processes, which are currently poorly understood.

Converting arable land into flowering fields changes functional and phylogenetic community structure in ground beetles

Agri-environmental schemes aim to promote biodiversity in agricultural landscapes. However, knowledge about the impact of these measures on diversity components beyond species richness, especially for non-target species and their ecological functions, is still very poor. Here, we investigated the response of ground beetle communities to the conversion of arable land into flowering fields, which are primarily installed to counteract pollinator loss in agricultural landscapes. We are focusing on the relationship between biodiversity components and the evolutionary relationship among functional groups.Land-use conversion from arable land to flowering fields has changed the phylogenetic community composition of ground beetles towards a phylogenetically clustered community. This is due to an increase in closely related medium-sized herbivorous species and a decrease in evolutionarily distinct small carnivorous species. Phylogenetic clustering did not result in a reduction of functional richness, but it increased the number of unique trait combinations of species within the local communities. This suggests a low ecological redundancy among herbivorous species. Because species richness, functional richness and phylogenetic diversity were unaffected by conversion, phylogenetic community structuring was predominantly driven by species turnover rather than by numerical changes.Flowering fields can act as refuges for herbivorous carabids that potentially affect the surrounding agricultural landscape by providing important ecosystem services such as weed control. To understand the impact of habitat transformation on carabid biodiversity, it was more informative to relate response traits to phylogenic and functional diversity than to use single diversity measures such as species richness. This conclusion might also apply to many other taxa.

Responses of boreal ground beetles (Coleoptera, Carabidae) to different logging regimes ten years post harvest

Most investigations of human impacts on biodiversity have been conducted within 1–3 years post-disturbance, although many biological responses develop over a longer period of time and annual community variation cannot be fully controlled. We therefore conducted a follow-up of carabid beetles over ten years in Norway spruce (Picea abies) dominated forests in Southern Finland, harvested using replicated logging treatments of different intensities. We collected carabids using pitfall traps in 1995 (prior to logging) and during four post-harvest seasons, 1996–98 (three first post-harvest summers) and 2006 (ten years after harvesting). The treatments were clear-cutting (no retained trees), modified clear-cutting (retention of three groups of 20–30 trees within a one-hectare plot) and gap cutting (three 0.16-ha openings within a one-hectare plot), and control (mature unharvested forest). (1) Total species richness and open-habitat carabids increased in gaps and in the two clear-cutting treatments, whereas forest carabids were slightly less abundant in clear-cuts than in the other treatments in 1997. These patterns were most evident in the second and third post-harvest summers. (2) Open-habitat carabids were less abundant and less speciose in both cleared and retained patches of gap cuts than in clear-cuts, Pterostichus adstrictus was more abundant in clear-cuts than in retained patches of modified clear-cuts or gap cuts, and carabid assemblage was more altered in both types of clear-cut than in gap cuts. (3) Ten years after logging, open-habitat carabid numbers were still elevated, whereas Calathus micropterus was less abundant, in the two types of clear-cut than in gap cuts or control stands. (4) We also found remarkable annual variation in carabid assemblages, such that was independent of logging. We conclude that even modest retention provides long-term support for forest carabids, but also that their full assemblage recovery takes longer than 10 years.

Survival under anthropogenic impact: the response of dragonflies (Odonata), beetles (Coleoptera) and caddisflies (Trichoptera) to environmental disturbances in a two-way industrial canal system (central Poland).

Ecological metrics and assemblages of three orders of aquatic insects (Odonata, Coleoptera and Trichoptera—OCT) in an industrial canal system affected by dredging were studied. Five sites (a river as a control site and canals) along the Vistula River in Central Poland were sampled during six sampling periods (2011 and 2013). Canonical correspondence analyses (CCA) was used to assess the influence of environmental variables on the distribution of 54 insect species in the following system of habitats—a river feeding the canals, river-fed inlet canals and outlet canals with cooling waters. Additionally, before and after control impact (BACI) was used to test for the impact of canal dredging in 2011 on the insect response metrics. Non-metric multidimensional scaling analysis differentiated insect assemblages of the three habitats and similarity percentage (SIMPER) indicated the species most responsible for the faunistic dissimilarities. Temperature was found to be a key factor governing the presence of insects in the outlet canals with cooling water. CCAs revealed that electrolytic conductivity (EC) and salinity had the greatest influence on the OCT fauna in the river and the inlet canals, whilst it was the dissolved oxygen and the level of development of aquatic plants that proved most important in the outlet canals. Modified ANOVAs showed that dredging significantly affected the mean species richness and the dominance in the canals. The changes in OCT species composition were highly informative. The comparison between tolerance patterns of the OCT orders against the five parameters (temperature, EC, total dissolved solids (TDS), pH and current) revealed that caddisflies are the most sensitive group, followed by Coleoptera while Odonata proved the most resistant. Dragonflies have the greatest potential to serve as bioindicators of industrially heated waters. The OCT fauna responded specifically to different environmental factors and stressors, it is strongly recommended to track the responses on different levels, not only metrics, but above all, species.

Various edge response of ground beetles in edges under natural versus anthropogenic influence: A meta-analysis using life-history traits

Edges are on the increase world-wide due to increasing fragmentation and loss of natural habitats. After formation, edges are maintained by various processes (natural vs. continued anthropogenic interventions: forestry, agriculture, urbanization) which influence the reaction of individual species to edge effects (history-based edge effect hypothesis), and this will be reflected in the diversity of assemblages. Diversity, however, is not the most appropriate indicator of the edge effect because species with different traits may respond differently to the edges. To further articulate the history-based edge effect hypothesis, we evaluated the edge effect on one of the most commonly used life-history traits, the feeding habit of ground beetles in forest edges. A meta-analysis based on 28 publications and 422 comparisons showed that natural vs. continued anthropogenic interventions as edge-maintaining processes reflected at the trait level. Abundance of herbivorous, omnivorous, and predatory ground beetle species were all higher in the natural edges than in the forest interiors, while no similar pattern occurred in edges with continued anthropogenic influence. These results suggest that structural and environmental changes at edges sustained by repeated anthropogenic influence adversely influencing ecosystem functions, with negative effects on ecosystem services like pest or weed control.

Essential oil in management of coconut rhinoceros beetle Oryctes rhinoceros L.

Plant derived essential oil is used as a component in management of coconut rhinoceros beetle Oryctes rhinoceros L. (Coleoptera: Scarabaeidae). A study was undertaken to evaluate the bioefficacy of essential oil from Ocimum basilicum, Eucalyptus citriodora, Trachyspermum ammi and their major constituent thymolin for management of O. rhinoceros. These essential oils derived from plant parts were characterized and their physiological response and biocidal activity was determined. Basil, citriodora, ajowan oil and thymol caused electrophysiological response in the antennae of O. rhinoceros adults. Behavioural response of beetles was tested in‘Y’ tube olfactometer having a choice between odour arm containing essential oil and control arm having zero air. Orientation of beetles to essential oil laden arm ranged from 15–30%. Over 70–85% of the beetles moved towards the control arm. Citriodora and basil oil inhibited hatching of 70% of eggs and also caused larval mortality. The mean larval mortality ranged from 61–66%. The repellence, ovicidal and growth regulating effect of essential oil offers an ecofriendly option in management of coconut rhinoceros beetle.