Beetle Communities Research Articles

Navigating the Semiochemical Landscape: Attraction of Subcortical Beetle Communities to Bark Beetle Pheromones, Fungal and Host Tree Volatiles.

Subcortical beetle communities interact with a wide range of semiochemicals released from different sources, including trees, fungi, and bark beetle pheromones. While the attraction of bark beetles, their insect predators, and competitors to bark beetle pheromones is commonly studied, the attraction of these beetle communities to other sources of semiochemicals remains poorly understood. We tested the attraction of bark and wood-boring beetles and their predators to host stress volatiles, fungal volatiles, and a mountain pine beetle lure in the field. Host stress volatiles were derived from lodgepole pine trees stressed by three fungal symbionts of mountain pine beetle and two common phytopathogens. Our results showed that bark beetles, particularly mountain pine beetles, show a preference for a combination of fungal volatiles, particularly 2-methyl-1-butanol and its lures. Without the addition of lures, 2-methyl-1-butanol was also identified as a key fungal volatile in the attraction of mountain pine beetle competitors from the Cerambycidae and Buprestidae families. Predators in the Elateridae and Staphylinidae families showed attraction to host stress volatiles and the healthy tree volatile profiles. These findings suggest that these semiochemicals warrant further field testing for potential use in monitoring and management of subcortical beetle populations.

Influence of Floral Strip Width on Spider and Carabid Beetle Communities in Maize Fields.

The study explored the impact of floral strip width on the spider and carabid beetle communities in maize fields over two years. Three widths of floral strips (2 m, 4 m, and 6 m) were compared with maize-only control strips to evaluate species diversity and distribution. The results showed significant differences in both spider and carabid populations between floral and control strips, with 4 m and 6 m widths consistently harboring higher biodiversity. The results also showed distinct community clustering within floral strips in 2021, which became more cohesive by 2022. Further analysis validated significant community dissimilarities between different strip widths and controls, highlighting the ecological advantages of wider floral strips for enhancing natural enemy biodiversity. Spider activity density was notably higher in floral strips than in adjacent farmland, peaking at the edges of 4 m-wide strips and decreasing in 6 m-wide strips, with the lowest density in 2 m-wide strips. Carabid beetle activity density varied considerably with strip width and proximity to the edge, typically peaking at the edges of wider strips. Spiders were more responsive to strip width than carabid beetles. Based on these findings, we suggest using 4 m- or 6 m-wide floral strips to enhance biodiversity and natural pest control in agricultural landscapes; the floral strips narrower than 4 m (such as 2 m) could not support optimal biodiversity, as spiders and carabid beetles do not disperse far into the maize field, with spiders having dispersal distances of less than 3 m and carabid beetles less than 10 m. Vegetation characteristics significantly influenced spider and carabid communities, impacting species richness, diversity indices, and community structures across two study years. These insights highlight the necessity of thoughtfully designing floral strips to enhance biodiversity and natural pest control in agricultural landscapes.

Morphometric variability of specimens in Ground Beetle (Carabidae) communities in agrarian landscape forests and protected areas

The change in the morphometric variable of ground beetles as well as in their volume (ellipsoidal biovol-ume) indicates the state of the biotope (unstable, stable), which is affected by anthropogenic activity such as forestry, agriculture and urbanisation. Between the years 2020 and 2022, we conducted research in flood-plain forests, which were located in agriculturally used land and in the important European territory of Du-najské Luhy Protected Landscape Area. Using the pitfall traps method, we recorded 1319 individuals be-longing to 29 species of ground beetles in six study areas representing two types of habitats (willow-poplar floodplain forest and regenerated poplar forest). We confirmed the largest average Ellipsoid Biovolume (EV) in the species Carabus coriaceus L. (2936 mm3), Carabus scheidleri Panzer (1427 mm3), Carabus vio-laceus L. (943 mm3), Carabus granulatus L. (366 mm3), Cychrus caraboides (L.) (336 mm3), Pterostichus niger (Schaller) (254 mm3), Harpalus rufipes (DeGeer) (123 mm3). The redundancy analysis confirmed the predominance of apterous and brachypterous species of ground beetles in forest stands in the Dunajské Luhy PLA (important European territory). These groups of Carabidae point to the ecological stability of bio-topes, because they inhabit habitats where they have optimum food. On the contrary, we confirmed the pre-dominance of macropterous species in forest biotopes in agrarian landscape conditions, which points to bi-otopes cyclically disturbed by anthropogenic activity. We recorded larger individuals in groups of apterous and brachypterous species in forest stands in the conditions of the Dunajské Luhy PLA. Larger macropter-ous individuals were recorded in forest stands in agrarian landscape conditions. In order to preserve forest habitats of European importance, it is necessary to know the ecological interactions between the ecosystem and ground beetles.

Habitat selection ecology of the aquatic beetle community using explainable machine learning

The aim of our work is to determine the importance of habitat features for the selection of the aquatic beetle community. Insects are represented by their general ecological traits such as body size, ecological element and trophic type, which are categorised into four body size ranges, four ecological groups and four trophic types. To determine the importance of habitat selection of the studied insects, we analysed the relationships between the above categories and the set of habitat features of the lake and its surroundings. Ensemble machine learning modelling (XGBoost-SHAP) revealed the mechanism of habitat feature selection in relation to the general ecological traits. We found strong interactions between the body size, ecological element and trophic type of beetles, suggesting that these general traits control the structure and functioning of the beetle community studied. The area of the lake and the features of beetle occurrence in the aquatic environment play an important but secondary role, and the importance of the characteristics of the lake’s riparian zone was minimised. We found several categories of beetles as they select the number of the same habitat features. The study can provide valuable information for the practical conservation and management of lake ecosystems.

Short‐Term Grasslands in Agriculture Support Both Natural Enemy and Phytophagous Arthropod Populations

ABSTRACTSimplified agricultural land with high chemical input is increasingly replacing natural habitats in many parts of the world. This loss and fragmentation of natural areas may have profound impacts on an array of wildlife, including predatory arthropods that provide natural biocontrol of agricultural pests. There is increasing interest in utilising short‐term seminatural habitat restoration in agricultural systems to support populations of beneficial organisms. We assessed the impact of two types of short‐term set‐asides on the diversity and abundance/activity density of phytophagous and predatory arthropods. We found that flower‐enhanced set‐asides supported higher abundances of both phytophagous and predatory arthropods compared to control crop fields. In addition, we found that both set‐aside types (flower enhanced and traditional) supported a more active and diverse community of beneficial predatory carabid beetles, with particularly strong trends in set‐asides supplemented with flowering plants. These results suggest that small‐scale, temporary, seminatural habitats in agricultural systems provide support for a diverse and abundant community of both beneficial and phytophagous arthropods.

Rove beetle species diversity and the patterns of interactions with their host plants in primary and secondary tropical forests

In tropical disturbed forests, it is relatively unknown the extent insect communities are experiencing shifts in species diversity and the consequences for ecosystem functions and services. In southern Mexico, we used the rove beetle community associated to Heliconia wagneriana bracts, as a model system, to investigate differences in community attributes and feeding habits between old-growth and human induced secondary forests. We tested if the beta diversity components of rove beetle communities were influenced by forest type and bract traits. Furthermore, we described the topology of individual-based heliconia-rove beetle ecological networks. Overall, we recorded 26 rove beetle species with significantly greater abundance in secondary forests. High compositional dissimilarity between forest types was observed with saprophagous species being more likely detected in old-growth forests; whereas predatory species in secondary forests. Heliconia-rove beetle networks showed a significant nested pattern with incidence data for old-growth forests and incidence and abundance data for secondary forests. Compared to old-growth forests, the rove beetle community in secondary forests showed strong shifts in species composition, diversity and differences in the detection probability of feeding habits, with consequences for ecosystem functioning. We further discuss these findings according to the forest disturbance and phytotelm systems. Implications for insect conservation: Individuals of H. wagneriana represent biodiversity reservoirs for invertebrates, especially in human-modified landscapes.

The Impact of Eucalyptus and Pine Plantations on the Taxonomic and Functional Diversity of Dung Beetles (Coleoptera: Scarabaeidae) in the Southern Region of Ecuador.

This study sheds light on the complex relationship between land use, biodiversity, and the functional traits of dung beetles in Ecuador. The results indicate that the richness and abundance of dung beetles vary across different land uses and regions, with forests generally having a positive impact, while eucalyptus and pine plantations have a negative effect in certain areas. Specific indicator species, such as Homocopris buckleyi for forest areas and Onthophagus curvicornis for eucalyptus plantations, were identified. This study also found that functional diversity analysis, based on morphological traits, revealed that certain traits, such as biomass, pronotum width, head width, and elytra length, were significant contributors to differences in dung beetle communities across various land uses and regions. This study highlights the potential conservation value of certain modified habitats and emphasizes the importance of considering both taxonomic and functional diversity when assessing the impact of land use on the ecosystem services provided by dung beetles. It underscores the potential value of plantations as refuges for dung beetle communities and the need for long-term assessments to better understand biodiversity changes over time.

Artificial tree microhabitats: Wound depth and position affect saproxylic beetles attracted to freshly veteranised trees

Abstract Veteran and ancient trees are key structures sustaining biodiversity in wooded landscapes. Their value depends on tree‐related microhabitats (TreMs) such as hollows, cracks and other structures related to wounds and wood decay. Decline and loss of veteran trees results in the loss of TreMs thus threatening the biodiversity associated with them. Veteranisation, that is, interventions aimed at creating or accelerating formation of rare TreMs in live trees, are thus increasingly applied to bridge gaps in habitat continuity and sustain the biodiversity associated with veteran trees. Several studies investigated the use of artificially created TreMs by various organisms. No study has, however, investigated saproxylic beetles attracted to freshly veteranised trees, and how different veteranisation techniques affect attractivity of veteranised trees to saproxylic beetles. We veteranised 48 sessile oaks using two types of deep and two types of shallow cuts and trapped saproxylic beetles on the veteranised and control trees in the first season after the intervention. The sampling yielded 280 species (6171 individuals) of saproxylic beetles, including 64 that are threatened. Veteranised trees attracted more abundant and diverse communities than control trees. Community composition differed between shallow and deep cuts and between the two types of deep cuts. Freshly veteranised trees thus attract diverse and abundant communities of saproxylic beetles consisting mainly of species potentially exploiting the wounds. The high proportion of threatened species, often associated with old oaks, suggests that veteranised trees benefit even some threatened saproxylic biodiversity already during the first year after the veteranisation.

The beetle fauna (Coleoptera) of the arctic mainland of Norway

This paper is the first attempt to summarize the beetles present in the arctic region of the mainland of Norway since 1946. In 1995 and 1998 beetles were collected by pitfall traps and other methods in Vardø municipality on the Varanger Peninsula in Finnmark county. This area is part of the small section of the Norwegian mainland that belongs to the southern arctic vegetation zone. A total number of 159 species from 18 families were recorded, including earlier findings by others. This probably covers a substantial part of the beetle fauna present in this marginal environment. Rove beetles (Staphylinidae) are the most abundant group and made up 46% of the recorded species, whereas diving beetles (Dytiscidae) and ground beetles (Carabidae) made up 16% and 15% of the species, respectively. Considering the regional distribution of these species in Norway, 8% are found only in northern Norway (Nordland/Troms/Finnmark), 19% have mainly an alpine distribution, 27% are mainly restricted to boreal areas, whereas 53% are common all over Norway. Diacheila polita and Simplocaria elongata belong to a characteristic arctic beetle community, and the present records of these two species are the only ones from Scandinavia. The study indicates that there are very few beetles that belong entirely to the arctic mainland of Norway.

Different habitat condition proportions on farms affect the structure and diversity of dung beetle (Coleoptera, Scarabaeidae, Scarabaeinae) communities

The continuous changes and increase of land use into ranching and agriculture have caused shifts in the composition and structure of dung beetle communities due to the modification of vegetation structure. The impact of these changes can be approached using dung beetles as ecological indicators. Agricultural, ranching, and forestry are often integrated into the same farm in different proportions (landscape level), and their degree of integration with habitats changes over time and space. We assessed if different habitat proportions of crop, pasture, and forest land on three farms affect the structure and diversity of dung beetle (Coleoptera: Scarabaeinae) communities. Farms included from three to four habitat conditions each (plantations of timber species, banana-coffee plantation, living fences, pastures, secondary and riparian forest). Pitfall traps with dung and carrion as bait were placed across each habitat condition of each farm during three different sampling periods. Across all samplings, 1,198 dung beetle individuals belonging to 21 species were captured. Species diversity and composition vary according to the type of farm and the main factor that modifies this tendency is the proportion of pasture land composing the farm. Farms with a lower proportion of grazing land (11.96% for forestry farms and 32.19% for agricultural farms) and denser vegetation canopy, which cast more shadows, had greater beetle diversity. Conversely, farms having a greater proportion of grazing land had low diversity and a dominant tendency in the species abundance curve. Umbraphile species dominated the forest farm, indicating a strong affinity for shaded environments such as the one provided there, while species displaying no habitat preference exhibited higher abundance in the ranching farm. Additionally, a notable prevalence of small-sized species was observed in the ranching farm, contrasting with a relatively even distribution of sizes in the remaining landscapes. These tendencies suggest that shade positively influences biodiversity conservation. Riparian vegetation, living fences, and banana-coffee plantations are important connectivity elements in agricultural landscapes for shade-adapted dung beetle species.

The White-backed Woodpecker (Dendrocopos leucotos) as an umbrella species for threatened saproxylic beetle communities in Central European beech forests

The umbrella species concept is a popular conservation planning tool which postulates that conservation schemes targeting a specific species will indirectly benefit many other sympatric species. In Scandinavia and Central Europe, the White-backed Woodpecker (Dendrocopos leucotos) is considered an umbrella species for woodland birds and cryptogam species of conservation concern. Whether this also applies to saproxylic beetles, a group of high conservation concern, remains open. Therefore, we tested that umbrella function in Central European beech forests that are currently recolonized by this woodpecker. Relying on radiotracking data, we compared saproxylic beetle communities within the breeding home ranges of White-backed Woodpeckers (high and low activity of the bird) against forests with ascertained absence of the bird (control). Bayesian inference for linear regressions identified that species richness of threatened saproxylic beetles was 1.51 (lower and upper 5 % PPCrI=[1.09; 2.01]) times higher in sites with high White-backed Woodpecker activity compared to the control. Community composition analyses on threatened saproxylic beetles showed a reduced β-diversity at low and high White-backed Woodpecker sites compared to the control. Finally, an indicator species analysis showed that 17 saproxylic beetle species, including 4 threatened species, were positively associated with White-backed Woodpecker’s breeding home ranges, while only 3 species, but no threatened species, were associated with the control sites. Overall, our results suggest that the White-backed Woodpecker plays the role of an umbrella species for threatened saproxylic beetle communities, opening new opportunities for conservation planning in European beech forests.

Duration of Cattle Ranching Affects Dung Beetle Diversity and Secondary Seed Removal in Tropical Dry Forest Landscapes.

Cattle ranching is an economic activity responsible for the loss of large extensions of tropical dry forest around the world. Several studies have demonstrated that the use of inadequate practices of this activity in tropical forests (e.g., fire, agrochemicals, and lack of rotational grazing systems of cattle in pastures) have negative consequences on dung beetle diversity and their ecological functions. In the present study, the influence of the cattle ranching duration gradient on the diversity of dung beetles and seed removal was evaluated. This study was carried out in pastures with different times of establishment of cattle ranching (between 4 and 40 years) in a tropical dry forest of Mexico. Overall, the species richness of dung beetles was similar along the gradient of grazing ages. However, the diversity of common (q1) and dominant (q2) species decreased and was associated with an increasing abundance of exotic species and a decreasing abundance of native species. Seed removal was mainly carried out by four beetle species, among which the exotic species Digitonthophagus gazella was the most important. The results establish that the duration of cattle ranching primarily influences the composition of dung beetle communities, as reflected in changes in the structure and function of their assemblages in the pastures. Although native dung beetles persist at low abundances along this gradient, the consequences of land use changes are undeniable in other similar ecosystems where these species could definitively disappear.

The influence of geographical distance on the decay of beetle community similarity: Native habitat and agricultural monocultures

The influence of geographical distance on the decay of beetle community similarity: Native habitat and agricultural monocultures

Landscape change and alien invasions drive shifts in native lady beetle communities over a century.

Understanding causes of insect population declines is essential for the development of successful conservation plans, but data limitations restrict assessment across spatial and temporal scales. Museum records represent a source of historical data that can be leveraged to investigate temporal trends in insect communities. Native lady beetle decline has been attributed to competition with established alien species and landscape change, but the relative importance of these drivers is difficult to measure with short-term field-based studies. We assessed distribution patterns for native lady beetles over 12 decades using museum records, and evaluated the relative importance of alien species and landscape change as factors contributing to changes in communities. We compiled occurrence records for 28 lady beetle species collected in Ohio, USA, from 1900 to 2018. Taxonomic beta-diversity was used to evaluate changes in lady beetle community composition over time. To evaluate the relative influence of temporal, spatial, landscape, and community factors on the captures of native species, we constructed negative binomial generalized additive models. We report evidence of declines in captures for several native species. Importantly, the timing, severity, and drivers of these documented declines were species-specific. Land cover change was associated with declines in captures, particularly for Coccinella novemnotata which declined prior to the arrival of alien species. Following the establishment and spread of alien lady beetles, processes of species loss/gain and turnover shifted communities toward the dominance of a few alien species beginning in the 1980s. Because factors associated with declines in captures were highly species-specific, this emphasizes that mechanisms driving population losses cannot be generalized even among closely related native species. These findings also indicate the importance of museum holdings and the analysis of species-level data when studying temporal trends in insect populations.

Tradeoffs in longleaf pine conservation: Prescribed fire management increases exotic ambrosia beetle abundance in pine-hardwood forests

Exotic woodboring insects, including some ambrosia beetles (Coleoptera: Curculionidae, Scolytinae, and Platypodidae), are threatening native forests worldwide. Longleaf pine (Pinus palustris Mill.) forest is an endangered habitat in the southeastern United States. One of the most important actions necessary for its conservation is prescribed fire, which maintains its savanna structure. However, prescribed fire is a forest disturbance, possibly creating new niches for colonization by exotic insects. The interaction between prescribed fire and exotic ambrosia species is understudied, especially in highly fire-dependent ecosystems. We carried out a two-year experiment in mixed longleaf pine forests in Alabama, USA. We compared ambrosia beetle communities in recently burned and unburned sites. We found that more than 66 % of total individuals in longleaf pine forests, regardless of fire management, were exotic species. Moreover, exotic ambrosia beetles were more abundant in burned stands, whereas native species showed no difference between burned or unburned stands. Fire management influenced stand species composition for native but not exotic ambrosia beetles. These results indicate that trade-offs exist in managing fire-dependent ecosystems, especially in the Anthropocene era, which is associated with rampant biological invasions. Fire is important to preserve the longleaf pine habitat, but it simultaneously acts as a disturbance, increasing the population density of those exotic species taking advantage of the presence of stressed or dying trees.

Community Composition of Alpine Dung Beetles Is Mostly Driven by Temperature and Habitat Type

In alpine environments, open habitats alternate with wood to create a habitat mosaic that shapes insect community composition and diversity. Dung beetles are an important group of insects specialized in feeding on vertebrate dung whose availability also depends on habitat type. Although the habitat preferences of dung beetles have been extensively studied, few studies have addressed the influence of habitat structure and temperature on dung beetle communities in alpine environments. We sampled dung beetles in pastures, at the edges between pasture and wood, in inner and outer woods of two alpine areas at different altitudes (two sites per area). We found that pastures had higher mean temperatures compared to other habitat types and hosted the highest number of species. However, the interaction between habitat and altitude significantly affected species richness and abundance, suggesting that habitat type and temperature modulate the response of dung beetles in the study area. Edges hosted intermediate communities between pastures and woodlands and were populated by both pasture and woodland specialists. Our results suggest that maintaining pastures is crucial to preserving dung beetle communities.

Composition and diversity of ground beetles within wooded pastures and alternative land-use systems in Swiss Jura mountains

AbstractWooded pastures combine trees and pastures in a land-use system resulting from traditional silvopastoral practices. With their sparse tree cover, wooded pastures represent an ecotone between open area pastures and forests with potentially high species diversity, although this is poorly tested for animal groups especially insects. In this study, we aimed to characterise and compare species communities in terms of species composition and diversity indices, biomass and ecological traits of ground beetles in wooded pastures, forests and non-wooded pastures. Pitfall traps were set up in 29 study sites located in the Swiss Jura mountains. Ground beetle communities in wooded pastures largely encompass those in open pastures and forests, although some species are found only in forests or open areas. Wooded pastures and open pastures have an equivalent species diversity level, which is significantly higher than the one in forests. Ground beetle diversity is positively correlated with the surfaces of Biodiversity Promotion Areas within a 100 m radius. Areas with high tree cover (70–100%) favour brachypterous and hygrophilic species, whereas areas with reduced tree cover (0–20%) favour xerophilic and winged species. Ground beetles’ size and biomass increase with tree cover. Wooded pastures are an important ecotone, ensuring a gradual change of land-use systems between open areas and forests, where a wide range of species from both land-use systems are found. These semi-natural systems are important for the conservation of ground beetles.

Vegetation succession and changes in carabid beetle (Coleoptera: Carabidae) communities in vineyards

Vineyards provide space for microhabitats and require a very specific way of management. Vineyard vegetation undergoes succession over time, which affects insect communities. The selected vineyards are located in Moravia in the Czech Republic. The vegetation of the vineyards consisted of 48 species of annual dicotyledons, 63 species of perennial dicotyledons, 9 species of annual grasses and 10 species of perennial grasses. During the observation, 9 species of carabid beetles were recorded in the monitored vineyards. The composition of the vegetation in the vineyards changes with the age of the vineyard. Over time, representatives of the perennial dicotyledons, perennial grasses groups increase and representatives of the group annual dicotyledons decrease. The age of the vineyards also changed the carabid beetle community – the species Anchomenus dorsalis was more common in older vineyards. The species Dolichus halensis, Leistus ferrugineus and Platynus assimilis were more frequently recorded in summer and fall in older vineyards. The other species preferred younger vineyards. A higher abundance was recorded in summer and fall, which may be due to a higher food supply and sufficient amount of microhabitats for hibernation.

Effects of climatic and time‐related variables on dung beetle communities: A case study in Central Spain

AbstractDung beetles are considered a key element in ecosystems as they are involved in many ecological processes, being one of the main decomposers of organic matter in the landscape. They can be classified into 3 subfamilies: Aphodiinae, Geotrupinae and Scarabaeinae, with each subfamily exhibiting specific adaptations and evolutionary strategies that have developed over time. The global patterns of dung beetle diversity are influenced by ecological factors, such as climatic (temperature, humidity, atmospheric pressure) and time‐related variables. Thus, the aim of the study is to see how these variables affect a dung beetle community and whether there are different responses among the subfamilies. The study was carried out in Mataelpino, a town located in Central Spain (Madrid, Spain). Monthly sampling was conducted from May 2018 to February 2020. According to the results the variables considered exert an effect on dung beetles, with differences observed among the subfamilies. To our knowledge, atmospheric pressure has been considered for the first time in a study of this type, with a greater effect being observed in the Aphodiinae subfamily than in the rest of the dung beetle groups. Regarding the other subfamilies, it has been observed that temperature is a determining factor for Scarabaeinae species, whereas humidity seems to have a greater effect on Geotrupinae species.

Species composition of dung beetles (Scarabaeiade: Scarabaeinae) from different habitat types in a protected area in eastern Africa

AbstractUnderstanding the composition and distribution of dung beetle species across various habitat types is crucial for elucidating their ecosystem functions. Dung beetles play pivotal roles in ecological processes such as nutrient cycling, seed dispersal and parasite suppression. Despite numerous studies on the influence of habitat types on dung beetle communities, knowledge gaps persist, particularly on how these beetles respond to different vegetation types in protected areas. In this study, we surveyed dung beetle species in Nyerere National Park, Tanzania, using baited pitfall traps across four habitat types: closed miombo woodland, open miombo woodland, marshland and riverine. We identified a total of 5534 individuals representing 63 species, 29 genera and nine tribes. Significant variations in species diversity were observed among the habitats, with the closed miombo woodland exhibiting the highest diversity and the open miombo woodland the lowest. Notably, certain species, such as Euoniticellus intermedius, Euonthophagus carbonarius, Gymnopleurus ignites, Onitis alexis, Onthophagus, Onthophagus vinctus, Onthophagus plebejus and Sisyphus goryi displayed a generalist distribution across all habitat types. Our findings underscore the critical importance of maintaining and conserving the quality of diverse habitat types to ensure the long‐term preservation of dung beetle biodiversity and the ecosystem services they provide. This study contributes valuable insights into dung beetle ecology and offers practical implications for ecosystem management and conservation strategies.