Beetle Assemblages Research Articles

Morphological differences on the mouthparts among six species of cockchafer (Coleoptera: Melolonthinae), with discussions on their feeding habits

Melolonthinae represent a megadiverse assemblage of scarab beetles, exhibiting dramatic diversity of feeding habits on the tribal or generic level. As the core feeding apparatus, mouthparts have been relatively underexplored morphologically among genera or tribes within Melolonthinae. In this study, we conducted a detailed dissection and scanning electron microscopic (SEM) analysis of the adult mouthparts from six species across four tribes within Melolonthinae, to provide new morphological characters. The mouthparts exhibit considerable morphological diversity, including variations in labral notches, invaginations on epipharynx, mandibular structures, and the arrangement of setae on the labia. Using SEM, we observed paired invaginations on the epipharynx in Brahmina faldermanni, Hilyotrogus bicoloreus, Polyphylla laticollis and Melolontha incana, which are absent in the Miridiba trichophora, and Apogonia niponica. The structural diversity may be linked to the different feeding habits of these beetles, a relationship that is briefly discussed in the study.

The association between pasture systems, dung removal and colonization by a local Australian temperate dung beetle assemblage

Abstract Herbivore dung quality (physical and chemical parameters) varies between animal species and animal diet which is influenced by seasonal fluctuations and farm management practices. Subsequently, this influences the reproductive success of dung beetles. In Australian pasture systems, how the introduced dung beetle assemblage interacts in the field with cattle dung derived from different resources is unknown. This study quantifies the colonization by dung beetles (abundance, species richness and evenness) and removal of cattle dung derived from three common temperate pasture systems (improved native, forage oat and rye/clover pasture, henceforth dung type) over 24 h for 12 months. From the three dung types, 13 species of dung beetle were captured. Abundance and species richness were influenced by month and transect, with weak evidence for differences between dung types influencing overall abundance: Onthophagus binodis (49.7%), Aphodius fimetarius (24.4%) and Labarrus lividus (17.1%) were the most abundant species. Dung removal (organic matter) was influenced by month and dung type, with more dung buried in improved native (23.9 g) and rye/clover (24.7 g) derived dung compared with forage oat (12.3 g) dung. Dung beetle abundance was positively correlated with removal of all dung types, with O. binodis biomass significantly influencing dung removal. This study showed that diet of bovine animals weakly influences the abundance of a local dung beetle assemblage, warranting further investigation on the influence of other dung types in different regions. Improvements to reporting of pasture species and growth stage is recommended for comparisons between dung derived sources.

Effects of heterogenous forest environments on ground‐dwelling beetles in a conifer plantation

AbstractIt is widely recognized that heterogeneous environments promote biodiversity. Consequently, we investigated whether heterogeneous environments influence the diversity of ground‐dwelling beetles within a well‐managed conifer plantation forest. We collected carabid beetles, and necrophagous silphid and dung beetles (necrophagous beetles) using pitfall traps at 37 sites with or without fish meat bait. The result of a two‐dimensional principal component analysis (PCA) utilizing environmental indices measured at each site suggested that the environmental heterogeneity depended on the survival density of planted conifers, serving as an indicator of historical gap formation levels. Gaps populated by invading broadleaved trees exhibited low canopy opening percentages and understory cover degrees, while those filled by the growth of planted conifers displayed the opposite conditions. The presence of bait had a negligible impact on carabid beetles but significantly influenced necrophagous beetles. No significant relationships were found between the scores of PCA components and the beetle species richness, suggesting that a heterogeneous environment does not increase the beetle species diversities. However, significant relationships were observed with the scores on nonmetric multidimensional scaling axes, indicating that a heterogeneous environment contributes to the complexity of beetle assemblages. The most dominant carabid, Synuchus cycloderus, was abundant in areas where historical gap formation was thought to be more prevalent. Among necrophagous beetles, Pherotrupes laevistriatus and Panelus parvulus preferred habitats with darker environments, in contrast to Onthophagus fodiens and O. nitidus. This study will aid in developing forestry practices aimed at conserving specific ground‐dwelling beetle species within conifer plantations.

Ground Beetle (Coleoptera: Carabidae) Assemblages in Hazelnut Groves in Calabria (Southern Italy)

Carabidae, or carabids, commonly known as “ground beetles”, are found in numerous natural and cultivated habitats and are recognized for their beneficial role in controlling phytophagous pests in various temperate agroecosystems. However, the crop type and agricultural practices used in management areas significantly affect the structure of the carabid communities. The aim of this study was to investigate the abundance and diversity of ground beetles in hazelnut agroecosystems characterized by different agricultural methods in Calabria, Southern Italy. The carabids were collected from 2017 to 2018 in three hazelnut groves referred to in this study as AZ1, AZ2 and AZ3. Carabids were sampled using pitfall traps inspected every two weeks over a period of 24 months. A total of 4665 specimens belonging to 48 taxa were collected within the sampled sites. Many taxa were found to be widely distributed across the three selected hazelnut groves. Among these, Calathus spp., Harpalus dimidiatus (P. Rossi, 1790), Nebria spp., Platyderus neapolitanus jannonei (Binaghi in Magistretti, 1955), Poecilus cupreus (Linnaeus, 1758), Pterostichus melas italicus (Dejean, 1828), and Syntomus obscuroguttatus (Duftschmid, 1812) were the most abundant ones associated with all sampled areas. Concerning trophic preference, among the collected taxa, the most abundant ones were zoophagous and zoospermophagous. Additionally, taxa uncommon in agroecosystems but with ecological relevance, such as Carabus lefebvrei lefebvrei Dejean, 1826, Carabus preslii neumeyeri Schaum, 1856, and Carabus rossii Dejean, 1826, were also collected.

Microhabitat and seasonal influence on bess beetle (Coleoptera: Passalidae) assemblage in Altitudinal Atlantic Forest

AbstractUnderstanding the spatiotemporal distribution of diversity has been a significant challenge in the field of conservation biology. Presently, there exists a limited understanding of the spatial distribution of passalid beetles within decomposing logs, as well as their distribution in microhabitats such as the cortex, heartwood and trunk–soil interface. Moreover, there is a scarcity of studies that delve into the temporal distribution patterns of passalid beetles. We evaluate the effect of seasons of the year and microhabitats on the distribution of passalid in an Altitudinal Atlantic Forest. More specifically, the effects of the period of the year and microhabitats were analysed on an assemblage scale and population structure scale. Collections were actively conducted monthly, during dry and rainy seasons, and distinct microhabitats of logs (tree cortex, heartwood and trunk–soil interface) were sampled. We discovered passalid galleries within 235 logs, housing a total of 785 individuals representing nine species across six genera and two tribes. Within the three examined microhabitats, the heartwood and cortex harboured the majority of individuals. In contrast, the trunk–soil interface microhabitat displayed reduced diversity and abundance and the absence of indicator species, exhibiting a distinct community structure compared with the others. The dry season stood out with a greater number of individuals, underscoring the influence of precipitation on passalid activity in this study. Our study contributes to understanding the ecological dynamics of these insects and evaluating their resilience to current landscape transformations on the planet.

Beetle assemblage distribution along edge–forest gradient in a managed oak forest

Abstract Forest management practices creating small‐scale forest edge habitats in managed forests have substantial impacts on the formation of beetle assemblages. In 2021, we conducted research in a managed oak woodland in Central Slovakia using three flight interception traps (FITs) to study beetle assemblages. Two FITs were installed at the forest edge, facing both, the clearing and the closed‐stand forest, while the third FIT was positioned 100 m within the closed‐canopy forest. We employed a novel methodological approach, which involved separately collected subsamples within the ecotone using FITs differentiated as ‘ecotone inwards’ and ‘ecotone outwards’ to capture distinct directional movements at the edge. We recorded 5.997 beetle specimens, encompassing 417 species across 284 genera and 58 families. We found that the species diversity and abundance of beetles were not significantly different between the FITs. However, the species composition was significantly different. The partial detrended canonical correspondence analysis suggests that these compositional differences might be closely associated with the distribution of trophic guilds, indicating varied responses to habitat modifications induced by forest edge creation. The results of our study showed that phloephagous, saproxylophagous, xylomycetophagous, xylophagous and zoophagous beetles exhibited a positive association with the forest edge, while mycophagous, phytophagous and saprophagous groups were distinctly associated with the closed‐canopy forest. Our analyses indicated that the ‘ecotone outward’ part of forest edges of managed forest may attract higher number of trophic groups, while the ‘ecotone inward’ part of the forest edge hosted high abundances of phloephagous and xylomycetophagous species.

Alpha and beta‐diversity and community structure of dung beetle assemblages in an East African protected savannah

AbstractFew studies have examined how dung beetle species composition changes across several mammalian dung types. Species composition and abundance of dung beetles were studied in dung samples of seven African mammals along animal trails and using 14 baited‐pitfall traps in both the park and the buffer zone resulting in a combined data set of 113 samples. Both the number of species (18) and the number of individual dung beetles (600) encountered were low for an area close to the Equator. Few species (2) and herbivores (13) tunnellers (9) dominated the dung beetles community, feeding and guild structure respectively. Alpha diversity was moderate 2.06 (1 < H′ ≤ 3). Beta diversity ranged from low 0.8 (high similarity) to high (zero, no similarity). Dung beetle species composition varied with dung type with the degree of pairwise similarity between two dung types in 19 of the total (21) dung beetle communities comparisons showing low similarity (0.4) to no similarity (zero). The observed discrepancies may be attributed to dung size, composition and consistency as well as to the low number of dung of the different animal species sampled. Furthermore, further research is needed as rarefaction curves suggest that sampling was incomplete.

Carabid beetles in solar parks: assemblages under solar panels are severely impoverished compared to gaps between panel rows and edge areas

Renewable energies are a major tool to reduce greenhouse gas emissions and combat climate change. Among renewables, solar parks are a key technology and their expansion will strongly increase in the future. Hence, there is a great need for research regarding their impact on biodiversity. In this study, we investigated the importance of three solar parks in northern Germany as habitat for carabid beetles. More specifically, we determined how habitat characteristics (temperature, vegetation structure), species richness, activity densities and carabid beetle assemblages vary between different locations within solar parks: areas under solar panels “UNDR”, gaps between panel rows “BTW” and areas at the edge of solar parks “EDGE”. We found that UNDR strongly differed from BTW/EDGE in terms of habitat conditions, species richness and activity densities of carabid beetles. UNDR mainly provided habitat for a species- and individual-poor subset of species already present in BTW/EDGE and made only a small contribution to the total species richness of the investigated solar parks. BTW and EDGE, on the other hand, differed only slightly. Thus, the narrow gaps between the panel rows were of similar importance as a habitat for carabid beetles as the edge areas. Overall, the investigated solar parks—and thus also the more species-rich areas EDGE and BTW—almost exclusively provided habitat for widespread and common non-threatened generalists, while species of conservation concern were extremely rare.Implications for insect conservationThe low importance of UNDR for carabid beetles should be considered when assessing the biodiversity value of solar parks, since a large proportion of these facilities is covered with solar panels. Between panel rows and at the edge of solar parks, larger areas should be kept free from construction with solar panels in order to provide habitats for carabid beetles and other species groups. More research should be conducted on how to further improve solar parks for carabid beetles and overall biodiversity.

Ecological Groups of Coleoptera (Insecta) as Indicators of Habitat Transformation on Drained and Rewetted Peatlands: A Baseline Study from a Carbon Supersite, Kaliningrad, Russia.

A total of 281 coleopteran species from 41 families were recorded from different sites of an abandoned cut-over peatland designated as the Carbon Measurement Supersite in Kaliningrad Oblast. This beetle assemblage is considered a baseline (pre-impact) faunal assemblage for further investigations during the 'before-after' (BA) or 'before-after control-impact' (BACI) study on a peatland that is planned to be rewetted. The spontaneously revegetated peatland has a less specialised beetle assemblage than at an intact raised bog. Tyrphobiontic species are completely absent from the peatland, while some tyrphophiles (5.3% of the total beetle fauna) are still found as remnants of the former raised bog communities. The predominant coenotic coleopteran group is tyrphoneutral generalists from various non-bog habitats (72.9%). The species composition is associated with the vegetation structure of the disturbed peatland (fragmentary Sphagnum cover, lack of open habitats, and widespread birch coppice or tree stand), which does not correspond to that of a typical European raised bog. The sampled coleopteran assemblage is divided into several relative ecological groups, whose composition and peculiarities are discussed separately. Possible responses to the rewetting measurements in different coleopteran groups are predicted and briefly discussed. A complex assemblage of stenotopic peatland-specialised tyrphophiles (15 spp.) and the most abundant tyrphoneutral generalists (31 spp.) were assigned as indicators for the environmental monitoring of peatland development.

Water Colour Shapes Diving Beetle (Coleoptera: Dytiscidae) Assemblages in Urban Ponds.

Dramatic land-use changes in urban landscapes can drive water colour darkening by washing compounds, such as organic matter and iron, from terrestrial ecosystems into urban blue space, consequentially affecting aquatic communities. Here, I studied how pond water colour changes along an urban gradient and how diving beetles (Dytiscidae) respond to the water colour gradient in 11 ponds with fish and 15 ponds without fish in the Helsinki Metropolitan Area, Finland. I found that the pond water colour exhibited a non-significant decreasing pattern along the urban gradient, indicating that urbanisation may not necessarily drive brownification in urban ponds. Dytiscid species richness and abundance exhibited significant positive correlations with increasing water colour in ponds with fish but no significant correlation in ponds without fish. Some species, such as Agabus spp. and Dytiscus spp., appeared tolerant to highly coloured water, whereas some species, such as Hyphydrus ovatus and Hygrotus spp., tended to occur in clear water, indicating that brown water may provide dytiscids with prey refuges, but some species are intolerant to brown water. The study highlights the importance of urban pondscape heterogeneity to meet the needs of aquatic invertebrates that prefer different water colours and for the multifunctioning of urban ponds.

Spatial distribution patterns of longhorn beetle assemblages (Coleoptera: Cerambycidae) in Mongolian oak forests in Changbai Mountains, Northeast, China

Spatial distribution patterns of longhorn beetle assemblages (Coleoptera: Cerambycidae) in Mongolian oak forests in Changbai Mountains, Northeast, China

Unraveling the biodiversity in the Brazilian wetlands: dung beetle assemblage in different vegetation types in the Araguaia Pantanal

ABSTRACT The Araguaia Pantanal is characterized by a mosaic of vegetation with high biodiversity. However, our understanding of this biodiversity remains limited and understudied. Therefore, the objective of this study was to evaluate the distribution patterns of dung beetles in different vegetation types (Deciduous Forest, Savanna, Riparian Forest, Murundu Fields, and Exotic Pastures). In addition, we analyzed how forest cover influence the species richness, abundance, and species composition of dung beetles. A total of 12,746 dung beetles representing 67 different species were captured and examined. Our findings revealed that the Murundu Fields exhibited lower species richness and abundance of dung beetles, indicating the influence of distinct vegetation types directly associated with flood pulses in the region. Furthermore, the species composition of the Murundu Fields was found to be a subset of the adjacent vegetation, primarily composed of Savanna and Deciduous Forest species. Additionally, our results demonstrated that tree cover played a significant role in driving dung beetle species turnover among the studied sites, highlighting the species’ response to the existing gradient of vegetational changes within the region. We believe that our study contributes valuable insights into the distribution and ecological dynamics of dung beetles in the Araguaia Pantanal.

Influence of environmental heterogeneity on the structure of the dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae) assemblage of the Cerrado savanna of northeastern Brazil

Influence of environmental heterogeneity on the structure of the dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae) assemblage of the Cerrado savanna of northeastern Brazil

First record of insects from the oldest and older Dryas of Altai (Russia). Coleoptera assemblages from Lebed River

Subfossil remains of insects found in the Lebed site (52.25220°N, 87.15692°E) located on the Lebed River, Altai Republic are recorded. The calibrated radiocarbon dates for two layers of these deposits were 16,461–17,056 cal BP, and 13,520–14,077 cal BP, which correspond to the oldest and older Dryas (Late Pleistocene). Insect assemblages of these deposits are mainly represented by Coleoptera, which are noteworthy there for high taxonomic and ecological diversity and include several endemic and relic species. At least 120 beetle species from 17 families have been found altogether, of them, 37 species are recorded for the Pleistocene deposits of Western Siberia for the first time. Three families, Carabidae, Staphylinidae and Curculionidae are most abundantly represented in the examined Lebed site. Ecologically, this beetle assemblage is dominated by species that are currently confined to the taiga belt and alpine meadows of the Altai Mountains; aquatic and near-water species are also well represented. The studied assemblages are rather different from the previously studied Pleistocene insect fauna in the south of the West Siberian Plain. The taxonomic and ecological compositions of the beetle fauna of Lebed site suggest its existence under humid palaeoclimate that was significantly colder than modern climate in this area.

Change in saproxylic beetle, fungi and bacteria assemblages along horizontal and vertical gradients of sun-exposure in forest

Microclimatic conditions in forests depend on canopy cover and thus differ between closed and open forests and similarly change along the vertical axis from the forest floor to the upper canopy. Yet, it is unknown whether this similarity in microclimatic conditions in forest gaps and the upper canopy provides equivalent habitats for wood-inhabiting species assemblages and thus, whether deadwood in the canopy is needed to maintain biodiversity. We tested this question for wood-inhabiting beetles, fungi and bacteria, using 150 branch bundles of Picea abies, Abies alba and Fagus sylvatica experimentally exposed along a vertical and horizontal gradient in microclimate: sun-exposed in the upper canopy and in gaps, half-shaded in the mid canopy and at the edge of forest gaps and shaded near ground under a closed canopy in a temperate forest in Central Europe. Variation partitioning showed that assemblage composition of all taxa was predominantly determined by tree species, followed by vertical stratum in beetles. Beetle assemblages at upper and mid-canopy formed a distinct community compared to those near ground. Fungal assemblages in the upper canopy were similar to those in gaps near the ground, while bacteria assemblages in the upper canopy were different only from those near ground under closed canopy. Our results indicate that the canopy stratum and sun-exposed deadwood enlarge the niche space for saproxylic organisms. Conservation strategies should thus aim at retaining habitat trees of different tree species with deadwood in the canopy as well as gaps with sun-exposed deadwood, e.g., after disturbances, to maintain biodiversity.

Structure of the Assemblages of Round Fungus Beetles (Leiodidae: Cholevinae and Leiodinae) Collected with Carrion-Baited Traps in Four Forest Types in the Haravéri Botanical Garden, San Sebastián Del Oeste, Jalisco, México

Structure of the Assemblages of Round Fungus Beetles (Leiodidae: Cholevinae and Leiodinae) Collected with Carrion-Baited Traps in Four Forest Types in the Haravéri Botanical Garden, San Sebastián Del Oeste, Jalisco, México

Structure of dung beetle assemblages (Coleoptera: Scarabaeidae: Scarabaeinae) in native forest and exotic pastures in the Southwest of the Brazilian Amazon

Structure of dung beetle assemblages (Coleoptera: Scarabaeidae: Scarabaeinae) in native forest and exotic pastures in the Southwest of the Brazilian Amazon

Response of Spider and Epigaeic Beetle Assemblages to Overwinter Planting Regimes and Surrounding Landscape Compositions.

The rotation patterns of summer rice-winter oil seed rape and summer rice-winter fallow are the main planting regimes in the rice ecosystem in southern China. However, the impact of local rotation patterns and landscape factors on the overwintering conservation of predators in spider and epigaeic beetle assemblages remains poorly understood. Here, we investigate the diversity and density of spiders and beetles over two consecutive winters (2019/2020 and 2020/2021), focusing on the impact of two rotation patterns (rice-fallow and rice-oilseed rape) and surrounding landscape compositions on predator diversity. The main findings of our research were that spiders were more abundant and had a higher activity density in the fallow rice fields (FRs) compared to the oilseed rape fields (OSRs), whereas ground beetles exhibited the opposite pattern. Specifically, fallow rice fields supported small and ballooning spiders (e.g., dominant spider: Ummeliata insecticeps), while OSRs supported larger ground beetles (e.g., dominant beetles: Agonum chalcomus and Pterostichus liodactylus). Moreover, the composition of spider assemblages were impacted by semi-natural habitats (SNHs) during overwintering, while ground beetle assemblages were influenced by overwinter planting patterns. Overall, our results suggest that different planting regimes and preserving semi-natural habitats are a strategic way to enhance species diversity and functional diversity of ground predators. It is, therefore, recommended that to conserve and improve predator diversity during overwintering, land managers and farmers should aim to maintain diverse planting regimes and conserve local semi-natural habitats.

The Influences of Rainfall Intensity and Timing on the Assemblage of Dung Beetles and the Rate of Dung Removal in an Alpine Meadow.

Changes in precipitation patterns, including rainfall intensity and rainfall timing, have been extensively demonstrated to impact biological processes and associated ecosystem functions. However, less attention has been paid to the effects of rainfall intensity and rainfall timing on the assembly of detritivore communities and the decomposition rate of detritus such as animal dung. In a grazed alpine meadow on the eastern Qinghai-Tibet Plateau, we conducted a manipulative experiment involving two levels of rainfall intensity (heavy rainfall, 1000 mL/5 min; light rainfall, 100 mL/5 min) and five levels of rainfall timing (0, 2, 4, 24, and 48 h after yak dung deposition). The aim was to determine the effects of rainfall intensity, timing, and their interaction on the assemblage of dung beetles and dung removal rate during the early stage (i.e., 96 h after yak dung deposition) of dung decomposition. Light rainfall significantly increased species richness in the treatment of 48 h after dung pats were deposited. Heavy rainfall significantly decreased beetle abundance in both the 0 h and 48 h treatments while light rainfall had no effect on beetle abundance. Dung mass loss was significant lower in the 2 h treatment compared to other treatments regardless of rainfall intensity. The structural equation model further revealed that the species richness of dung beetles and dung mass loss were significantly affected by rainfall timing but not by rainfall intensity. However, no significant relationships were observed between any variables examined. These findings suggest that changes in precipitation patterns can influence both the structure of dung beetles and the rate of dung decomposition but may also decouple their relationship under a certain circumstance. Therefore, it is crucial to pay greater attention to fully understand local variability between the biological processes and ecosystem functions within a global climate change scenario.

Ground beetle assemblages inhabiting various age classes of Norway spruce stands in north-eastern Poland.

Assemblages of epigeic ground beetles living in Norway spruce forests in north-eastern Poland in three age ranges: young: 20-30 years (A); middle-aged: 40-50 years (B); old: 70-80 years (C) were investigated. In each age category, 4 plots with 5 Barber traps were set up. Ground beetle assemblages were compared in terms of their abundance, species richness, and the Shannon H' index value. Quantitative ecological description of the carabids captured in the analysed age-classes of Norway spruce forests was performed, and the values of the mean individual biomass (MIB) were calculated. To determine the correlation between mean individual biomass and abundance of various ecological groups of carabid beetles, the Spearman rank correlation coefficient was calculated. The assemblages of ground beetles living in the Norway spruce forests in north-eastern Poland were characterised by quite large species richness (44 species in total). There were significant differences in species richness among the different ages of Norway spruce forests. The oldest Norway spruce stands (70-80 years old) had a smaller number of species and specimens of ground beetles as well as the highest MIB values in comparison with the younger spruce forests A and B. The results revealed that high MIB values were positively correlated with the presence of large ground beetle species with higher moisture requirements. Lower values of the MIB index were due to the presence of smaller open habitat macropterous species, with the spring type of breeding and associated with open areas.