Effects of Degradation and Replacement of Southern Brazilian Coastal Sandy Vegetation on the Dung Beetles (Coleoptera: Scarabaeidae)

In this paper we address the effects of anthropogenic disturbance and replacement of Brazilian Coastal sandy vegetation (restingas) on dung beetles communities. We sampled dung beetles in the four main vegetative physiognomies of Guriri Island, Espírito Santo State: forest restinga, restinga Clusia, disturbed restinga (from burning events), and pastures. We placed four sets of two pitfall traps (baited with horse and human dung) in four independent areas of each vegetation type, and collected 14,534 individuals of 13 dung beetle species. Neither log₁₀ of individuals nor log₁₀ of species richness were good predictors of restinga disturbance. However, a significant amount of variation in dung beetle abundance and richness could be explained by bait type. Ordination of these sites using hybrid multidimensional scaling revealed a gradient of habitat disturbance from undisturbed restinga samples to pasture. Dung beetle communities along this gradient demonstrated a complete turnover in species composition, from restinga‐specialists to invasive and generalists species respectively. This complete turnover signals the local extirpation of forest‐adapted species in disturbed and converted areas. Only a single dung beetle species in preserved restingas is protected by Brazilian law (Dichotomius schiffleri). Given the extent of the clearing of restinga habitat, the conservation status of dung beetles associated with restinga forest gives cause for concern.     

Changes in the dynamics of functional groups in communities of dung beetles in Atlantic forest fragments adjacent to transgenic maize crops

We investigated the composition and structure of dung beetle communities (Coleoptera, Scarabaeidae, Scarabaeinae) inhabiting areas of forest fragments next to either conventional or Bt-transgenic maize crops. The purpose of the study was to examine possible impacts of transgenic plants on non-target organisms associated with mammals through their food chain. In February 2011, we collected a total of 1502 beetles belonging to 33 species in Campos Novos, Santa Catarina state (SC), Brazil. Beetles were captured using 200 pitfall traps distributed among 20 forest fragments, 10 fragments in each site type (adjacent to conventional vs. Bt crops). In the fragments adjacent to conventional maize, 805 dung beetles from 27 species were collected. In the fragments adjacent to Bt-transgenic maize, 697 dung beetles from 27 species were caught. Dung beetle community composition was affected by fragment size and environmental complexity, and by distance between fragments. However, it did not explain the differences related to the two crop types, i.e., the functional group of dwellers was significantly over-represented in the fragments surrounded by transgenic maize. Hence, the dweller species Eurysternus francinae and Eurysternus parallelus were more frequent and abundant in fragments located near the transgenic maize, while the tunneler species Onthophagus tristis, Uroxys terminalis, Ontherus sulcator and the roller species Canthon lividus seminitens were more frequent and abundant in fragments surrounded by conventional maize. This observed impact of transgenic crops on functional group dynamics within dung beetle communities could potentially lead to impaired capacity for feces removal, seed dispersal, edaphic aeration, and incorporation of organic matter in the soil in these areas, as such ecosystem services are not performed by the dominant functional group (i.e., dwellers).     

Vertical Stratification Responses of an Arboreal Dung Beetle Species to Tropical Forest Fragmentation in Malaysia

Little is known about how arboreal arthropods respond to forest disturbance. We assessed how rain forest fragmentation affected the vertical stratification of arboreal dung beetles in Peninsular Malaysia. An arboreal dung beetle species (Onthophagus sp.) moved closer to the forest floor in smaller fragments, suggesting a downward shift in its foraging possibly in response to fragmentation.     

Fire? They don't give a dung! The resilience of dung beetles to fire in a tropical savanna

1. Disturbance is a strong driver of community assembly and fire has long been recognised as one of the main disturbances of terrestrial ecosystems. This study tested the resilience of dung beetles to fire events in campos rupestres, which is a tropical savanna ecosystem that evolved under a frequent fire regime, by assessing the resistance and recovery of their communities. 2. Dung beetles were sampled before and after a fire event and the effect of fire on dung beetle richness, abundance, mean community biomass and composition was tested. The effects of time since last fire and fire frequency on the community were also tested. 3. No effect of fire occurrence, time since last fire and fire frequency on any community variable was found. 4. Some non‐mutually exclusive mechanisms promoting the resistance and recovery of dung beetles in campos rupestres could be acting in synergy. One potential mechanism is the mismatched seasonality between fire events and dung beetle occurrence, as fires occur during the dry season and dung beetles are present above ground during the rainy season. Furthermore, dung beetles are insects that remain buried during most of their lifetime, which could protect individuals from being burned. Another potential mechanism is the replacement of species in burned areas by the movement of individuals from unburned areas, attracted by resources and/or by metacommunity dynamics. 5. It is concluded that in this ‘fire‐dependent’ ecosystem, dung beetle communities are resilient to fire and seem not to be structured by this disturbance.     

Changes of dung beetle communities from rainforests towards agroforestry systems and annual cultures in Sulawesi (Indonesia)

Little is known about how tropical land-use systems contribute to the conservation of functionally important insect groups, including dung beetles. In a study at the margin of Lore Lindu National Park (a biodiversity hotspot in Central Sulawesi, Indonesia) dung-beetle communities were sampled in natural forest, young secondary forest, agroforestry systems (cacao plantations with shade trees) and annual cultures (maize fields), each with four replicates (n = 16 sites). At each site we used 10 pitfall traps, baited with cattle dung, along a 100 m transect for six 3-day periods. The number of trapped specimens and species richness at the natural forest sites was higher than in all land-use systems, which did not significantly differ. Each land-use system contained, on average, 75% of the species richness of the natural forest, thereby indicating their importance for conservation. However, a two-dimensional scaling plot based on NESS indices (m = 6) indicated distinct dung beetle communities for both forest types, while agroforestry systems and annual cultures exhibited a pronounced overlap. Mean body size of dung beetles was not significantly influenced by land-use intensity. Five of the six most abundant dung beetle species were recorded in all habitats, whereas the abundance of five other species was significantly related to habitat type. Mean local abundance and number of occupied sites were closely correlated, further indicating little habitat specialisation. The low dung beetle diversity (total of 18 recorded species) may be due to the absence of larger mammals in Sulawesi during historical times, even though Sulawesi is the largest island of Wallacea. In conclusion, the dung beetle fauna of the lower montane forest zone in Central Sulawesi appears to be relatively robust to man-made habitat changes and the majority of species did not exhibit strong habitat preferences.     

Species diversity and community structure of rove beetles (Coleoptera: Staphylinidae) attracted to dung of sika deer in coniferous forests of southwest Japan

Insect communities of mammal dung have been known as excellent model ecosystems for scientific study. Ecological surveys of diversity and seasonal patterns of coprophilous rove beetles in relation to wild mammals have rarely been conducted, although the high potential species diversity and abundance of the rove beetles are known. In order to investigate biodiversity of these beetles, we analyzed species composition, abundance, feeding guild and seasonality of rove beetles that were attracted to sika deer Cervus nippon dung by using dung‐baited pitfall traps for a 1.5‐year study in two plantations (cypress, cedar) and one secondary natural forest (pine) in Fukuoka Prefecture, southwest Japan. Consequently, saprophagous Anotylus sp. (Oxytelinae) was dominant in all forests. Analyses of feeding guild structure showed the number of individuals were dominated by saprophagous beetles, but the number of species were dominated by predatory beetles. Seasonal effects suggested that the species richness and abundance of rove beetles are possibly regulated by scarabaeoid dung beetles. These findings feature one example of a coprophilous rove beetle community.     

Patterns of alimentary resource use by dung beetles in introduced Brazilian pastures: Cattle versus sheep dung

Dung beetles (Coleoptera: Scarabaeidae) perform essential ecological functions in pastures, such as dung removal, nutrient recycling and parasite control. However, the patterns of alimentary use by dung beetles in introduced Brazilian pastures are poorly known. Here, we compared dung beetle species richness, abundance and species composition in cattle and sheep dung, and identified the dung beetle species preference by each dung type. In January 2019, dung beetles were sampled with pitfall traps baited with cattle and sheep dung in 12 introduced pastures (Urochloa spp.), in Aquidauana, Mato Grosso do Sul, Brazil. A total of 592 individuals belonging to 14 species of dung beetles were collected. Of the 14 species sampled, nine were recorded in both dung types, five were found exclusively in sheep dung and no species was exclusive to cattle dung. Species richness and abundance were higher in sheep dung. Species composition was different between the dung types. Dichotomius bos (Blanchard), Genieridium bidens (Balthasar), Onthophagus aeneus Blanchard and Trichillum externepunctatum Preudhomme de Borre were associated with sheep dung. Our results provide evidence that sheep dung is more attractive to dung beetles with a distinct community species between the two dung types, although the studied pastures have never been used before for sheep breeding. Thus, our data shows that the introduction of a new alimentary resource (e.g. sheep dung) can be an important strategy to help to obtain a more diverse dung beetle assemblage in introduced Brazilian pastures.     

Diversity and seasonal fluctuations in dung beetle (Coleoptera) community in Kurukshetra,India

Five pitfall traps baited with 150–200 g of fresh cattle dung were installed for 24 h at weekly intervals. A total of 991 dung beetles from 11 genera, 31 species and three subfamilies was obtained. The community was dominated by Oniticellus spinipes individuals by 32.3%. Ten species appeared only once during the collection period and species composition and dominance changed throughout the period. The overall pattern we detected in the organization of the dung beetle community is that the species richness, abundance and diversity rise in September and the 2^nd week of October. The dung beetle community was found to be affected by season.     

El Niño impacts on human-modified tropical forests: Consequences for dung beetle diversity and associated ecological processes

Our knowledge of how tropical forest biodiversity and functioning respond to anthropogenic and climate-associated stressors is limited. Research exploring El Niño impacts are scarce or based on single post-disturbance assessments, and few studies assess forests previously affected by anthropogenic disturbance. Focusing on dung beetles and associated ecological functions, we assessed (a) the ecological effects of a strong El Niño, (b) if post-El Niño beetle responses were influenced by previous forest disturbance, and (c) how these responses compare between forests impacted only by drought and those affected by both drought and fires. We sampled 30 Amazonian forest plots distributed across a gradient of human disturbance in 2010, 2016, and 2017—approximately 5 years before, and 3–6 and 15–18 months after the 2015–16 El Niño. We found 14,451 beetles from 98 species and quantified the beetle-mediated dispersal of >8,600 seed mimics and the removal of c. 30 kg of dung. All dung beetle responses (species richness, abundance, biomass, compositional similarity to pre-El Niño condition, and rates of dung removal and seed dispersal) declined after the 2015–16 El Niño, but the greatest immediate losses (i.e., in 2016) were observed within fire-affected forests. Previous forest disturbance also influenced post-El Niño dung beetle species richness, abundance, and species composition. We demonstrate that dung beetles and their ecological functions are negatively affected by climate-associated disturbances in human-modified Amazonian forests and suggest that the interaction between local anthropogenic and climate-related stressors merits further investigation.     

Do riparian reserves support dung beetle biodiversity and ecosystem services in oil palm-dominated tropical landscapes?

Agricultural expansion and intensification are major threats to global biodiversity, ecological functions, and ecosystem services. The rapid expansion of oil palm in forested tropical landscapes is of particular concern given their high biodiversity. Identifying management approaches that maintain native species and associated ecological processes within oil palm plantations is therefore a priority. Riparian reserves are strips of forest retained alongside rivers in cultivated areas, primarily for their positive hydrological impact. However, they can also support a range of forest‐dependent species or ecosystem services. We surveyed communities of dung beetles and measured dung removal activity in an oil palm‐dominated landscape in Sabah, Malaysian Borneo. The species richness, diversity, and functional group richness of dung beetles in riparian reserves were significantly higher than in oil palm, but lower than in adjacent logged forests. The community composition of the riparian reserves was more similar to logged forest than oil palm. Despite the pronounced differences in biodiversity, we did not find significant differences in dung removal rates among land uses. We also found no evidence that riparian reserves enhance dung removal rates within surrounding oil palm. These results contrast previous studies showing positive relationships between dung beetle species richness and dung removal in tropical forests. We found weak but significant positive relationships between riparian reserve width and dung beetle diversity, and between reserve vegetation complexity and dung beetle abundance, suggesting that these features may increase the conservation value of riparian reserves. Synthesis and applications: The similarity between riparian reserves and logged forest demonstrates that retaining riparian reserves increases biodiversity within oil palm landscapes. However, the lack of correlation between dung beetle community characteristics and dung removal highlights the need for further research into spatial variation in biodiversity–ecosystem function relationships and how the results of such studies are affected by methodological choices.     

Tamarins and Dung Beetles: An Efficient Diplochorous Dispersal System in the Peruvian Amazonia

Dung beetles fulfill several key functions in ecosystems but their role as secondary seed dispersers is probably one of the most complex ones. Various factors, such as seed characteristics, dispersal pattern induced by the primary disperser, season, and habitat, can affect the seed–beetle interaction. Particularly little is known about the fate of seeds primarily dispersed in small feces. The aim of this study was to investigate the effects of these factors on the dung beetle community (species composition, number and size of individuals) and its consequences on burial occurrence and depth of seeds primarily dispersed by two tamarin species. We captured dung beetles in a Peruvian rain forest with 299 dung‐baited pitfall traps to characterize the dung beetle community. Seed burial occurrence and depth were assessed by marking in situ 551 dispersed seeds in feces placed in cages. Among these seeds, 22.5 percent were buried by dung beetles after 2 d. We observed a significant effect of the amount of dung, season, time of deposition, and habitat on the number of individuals and species of dung beetles, as well as on seed burial occurrence and depth, while the tamarin species significantly influenced only the number and the size of dung beetles. This seed dispersal loop is particularly important for forest regeneration: small to large seeds dispersed by tamarins in secondary forest can be buried by dung beetles. These seeds can thus benefit from a better protection against predation and a more suitable microenvironment for germination, potentially enhancing seedling recruitment.     

Effects of Season and Vegetation Type on Community Organization of Dung Beetles in a Tropical Dry Forest1

Dung beetles are important components of most terrestrial ecosystems. In tropical rain forests, dung beetle communities can be very rich in number of species and individuals, and they are known to be useful bioindicators of habitat disturbance. In contrast, very little is known about the organization of dung beetle communities in tropical dry forests. The aim of this study was to describe in detail the dung beetle community of a Mexican tropical dry forest and to assess the relative importance of rainfall seasonality and forest structure in affecting the temporal and spatial dynamics of this community. Dung beetles were captured with pitfall traps at the beginning of the rainy season, the middle of the rainy season, and the middle of the dry season, in two distinct forest types: deciduous forest (DF) and semideciduous forest (SDF) at the Estación de Biología Chamela. Both rainfall seasonality and forest structure affected the community organization of dung beetles. During both rainy periods, 14 species were captured, but only three during the dry season. Dung beetles captured during the dry season were only found in the SDF. When comparing the beginning and the middle of the rainy season, differences in abundance and guild structure were also observed between both periods and between forest types, but these differences were much less pronounced.     

Do pygidial secretions of dung beetles have the potential to repel urban pest ants?

Various organisms emit malodorous secretions against competitors, and the potential use of these secretions in pest management should be investigated. For example, some ant species feed on similar resources as dung beetles, which might have led to counter chemical defences in dung beetles. We tested whether pygidial secretions of the dung beetle Canthon smaragdulus (Fabricius) (Coleoptera: Scarabaeidae, Scarabaeinae) alter the locomotor behaviour of the exotic urban pest ant Tapinoma melanocephalum (Fabricius) (Hymenoptera: Formicidae), specifically whether these secretions repel those ants. We also tested whether the disturbance in the locomotor behaviour of T. melanocephalum increases with the amount of pygidial secretion. We found that individual T. melanocephalum displayed changes in their locomotor behaviour when exposed to pygidial secretions of coupled dung beetles, single males, and single females. Additionally, the pygidial secretions from male and female dung beetles could repel ants. The change in the locomotor behaviour of T. melanocephalum increased with the amount of pygidial secretion. Our results suggest that the pygidial secretions of dung beetles have potential as a biological repellent of T. melanocephalum. Hence, pygidial secretions from dung beetles may be used in the future for the development of urban pest management strategies.     

Dung beetle diversity and functions suggest no major impacts of cattle grazing in the Brazilian Pantanal wetlands

1. Dung beetles perform relevant ecological functions in pastures, such as dung removal and parasite control. Livestock farming is the main economic activity in the Brazilian Pantanal. However, the impact of cattle grazing on the Pantanal's native dung beetle community, and functions performed by them, is still unknown. 2. This study evaluated the effects of cattle activity on dung beetle community attributes (richness, abundance, biomass, composition, and functional group) as well as their ecological functions (dung removal and soil bioturbation) in the Pantanal. In January/February 2016, dung beetles were sampled and their ecological functions measured in 16 sites of native grasslands in Aquidauana, Mato Grosso do Sul, Brazil, 10 areas regularly grazed by cattle and six control ungrazed areas (> 20 years of abandonment). 3. In all, 1169 individuals from 30 species of dung beetles were collected. Although abundance, species richness, and biomass did not differ between grasslands with and without cattle activity, species composition and functional groups differed among systems. Large roller beetles were absent from non‐cattle grasslands, and the abundance, richness, and biomass of medium roller beetles was higher in those systems. 4. Despite causing changes in species/functional group composition, the results of this study show that a density compensation of functional groups in cattle‐grazed natural grasslands seems to have conserved the ecological functions (dung removal and soil bioturbation), with no significant differences between systems. 5. Therefore, these results provide evidence that cattle breeding in natural grasslands of the Brazilian Pantanal can integrate livestock production with the conservation of the dung beetle community and its ecological functions.     

Relationship between land uses and diversity of dung beetles (Coleoptera: Scarabaeinae) in the southern Atlantic forest of Argentina: which are the key factors?

The loss of natural habitats is one of the main drivers of biodiversity decline. Anthropogenic land uses preserving biotic and abiotic conditions of the native ecosystem are more suitable to preserve the native biodiversity. In this study, we explored changes in species richness and composition in different land uses of the southern Atlantic forest, considering three independent factors: (1) canopy (presence–absence), (2) type of vegetation (native–exotic) and (3) livestock (presence–absence). We expected a gradient of response in the richness and composition of the native forest dung beetle community, from land uses preserving canopy and native vegetation to open land uses with exotic vegetation. Dung beetles were sampled in protected native forests and four land uses, using two potential food resources: human dung and carrion. The species richness and composition of each habitat, as well as differences in composition and the influence of factors over diversity, were then analyzed. As expected, our results showed that land uses preserving canopy and native vegetation maintain the dung beetle diversity of the native forest. Moreover, while the three factors analyzed influenced dung beetle diversity, canopy cover was the main driver of dung beetle diversity loss. The main conclusion of this study is that the conservation of canopy (either native or exotic) is determinant to preserve highly diverse dung beetle communities and subsequently, the ecological functions performed by this taxon. However, the ecophysiological mechanism behind the response of dung beetles to habitat disturbance is poorly understood.     

Not all dung beetles feed on dung: Scarabaeinae (Coleoptera: Scarabaeidae) attracted to different carrion types in contrasting habitats at Brazilian Amazon

By understanding how assemblages segregate according to food types, it is possible to depict and understand species distribution and exploitation of similar food resources. Although it is well known that dung beetles may feed on carrion, but the attractiveness of different carrion types for these beetles is still poorly understood. In this study, we compared the dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae) diversity attracted to two carrion types in different habitats in an Amazonian landscape. Dung beetles were captured by using pitfall traps baited with decaying cattle beef and cattle liver in native forest, peach palm plantation, teak plantation and exotic pasture. Overall, we captured 582 dung beetles of 43 species, where Canthidium aff. lentum was classified as a specialist of cattle beef, Deltochilum sp. One was considered specialist of liver carrion, 11 were considered generalists and for the 30 remaining species, it was not possible to determine their carrion preference due to the low number. Abundance, but not species richness, was affected by carrion type, and a higher number of beetles was recorded in beef-baited traps compared to liver-baited traps. According to functional groups, endocoprid beetles were more abundant in traps baited with decaying beef, while paracoprid and telecoprid beetles did not show preference for any carrion type. This study suggests a novel scenario of intra-resource segregation, where species vary their preferences depending to the part of the dead corpse being exploited. The amount of food resource, the maintenance of stable populations and trophic preference mediated by chemical cues are some mechanisms that may explain the segregation of dung beetles among carrion types.     

Gut microbiota of dung beetles correspond to dietary specializations of adults and larvae

Vertebrate dung is central to the dung beetle life cycle, constituting food for adults and a protective and nutritive refuge for their offspring. Adult dung beetles have soft mandibles and feed primarily on nutritionally rich dung particles, while larvae have sclerotized mandibles and consume coarser dung particles with a higher C/N ratio. Here, using the dung beetles Euoniticellus intermedius and E. triangulatus, we show that these morphological adaptations in mandibular structure are also correlated with differences in basic gut structure and gut bacterial communities between dung beetle life stages. Metagenome functional predictions based on 16S rDNA characterization further indicated that larval gut communities are enriched in genes involved in cellulose degradation and nitrogen fixation compared to adult guts. Larval gut communities are more similar to female gut communities than they are to those of males, and bacteria present in maternally provisioned brood balls and maternal ‘gifts’ (secretions deposited in the brood ball along with the egg) are also more similar to larval gut communities than to those of males. Maternal secretions and maternally provisioned brood balls, as well as dung, were important factors shaping the larval gut community. Differences between gut microbiota in the adults and larvae are likely to contribute to differences in nutrient assimilation from ingested dung at different life history stages.     

First Quantitative Study of Rove Beetles in Oklahoma Winter Wheat Fields

Adult rove beetles (Staphylinidae) were sampled every 7–14 days from one winter wheat field located in each of the four major wheat growing regions of Oklahoma during the 1999–2000 and 2000–2001 growing seasons. The number of cereal aphids per tiller, wheat plant growth stage, and wheat tiller density also were estimated. A total of 12 genera representing 13 species of beetles were collected from the field. The density of rove beetles was generally low, ranging from 0.003 beetles per m² in fall to 0.106 beetles per m² in spring. Rove beetle communities differed among seasons. After accounting for the effect of season, there was no statistically significant association between rove beetle community structure and field location, aphid density, wheat plant growth stage, or wheat plant density. Most rove beetle species showed no association with a particular season, however, Aleochara notula Erichson, Lathrobium sp., and Oxypoda sp. were present predominantly in fall, while Bisnius inquitus Erichson was associated with winter. Oxypoda sp. was the most abundant rove beetle in winter wheat fields in spring and was relatively abundant in winter, but was not collected from wheat fields in fall. Tachyporus jocosus Say was present in wheat fields during all seasons. T. jocosus was the most abundant rove beetle species in the winter wheat fields in fall and winter and was the second most abundant species during spring.     

Does natural reforestation represent a potential threat to dung beetle diversity in the Alps?

Traditional agro-pastoral practices are in decline over much of the Alps, resulting in the complete elimination of livestock grazing in some areas. Natural reforestation following pastoral abandonment may represent a significant threat to alpine biodiversity, especially that associated with open habitats. This study presents the first assessment of the potential effects of natural reforestation on dung beetles by exploring the relationships between the beetle community (abundance, diversity, species turnover and assemblage structure) and the vegetation stages of ecological succession following pastoral abandonment. A hierarchical sampling design was used in the montane belt of the Sessera Valley (north-western Italian Alps). Dung beetles were sampled across 16 sampling sites set in four habitat types corresponding to four different successional stages (pasture, shrub, pioneer forest and beech forest) at two altitudinal levels. The two habitats at the extremes of the ecological succession, i.e. pasture and beech forest, had the greatest effect on the structure of local dung beetle assemblages. Overall, dung beetle abundance was greater in beech forest, whereas species richness, Shannon diversity and taxonomic diversity were significantly higher in pasture, hence suggesting this latter habitat can be considered as a key conservation habitat. Forests and pastures shared a lower number of species than the other pairs of habitats (i.e. species turnover between these two habitats was the highest). The two intermediate seral stages, i.e. shrub and pioneer forest, showed low dung beetle abundance and diversity values. Local dung beetle assemblages were also dependent on season and altitude; early-arriving species were typical of pastures of high elevation, whereas late-arriving species were typical of beech forests. It is likely that grazing in the Alps will continue to decrease in the future leading to replacement of open habitats by forest. This study suggests therefore that, at least in the montane belt, reforestation may have potentially profound and negative effects on dung beetle diversity. Maintaining traditional pastoral activities appears to be the most promising approach to preserve open habitats and adjacent beech forests, resulting in the conservation of species of both habitats.