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Structure and Composition of Dung Beetle Assemblages (Coleoptera: Scarabaeidae) in a Livestock Ranch in Central Uruguay: Responses of Functional Groups and Species to Local Habitats and Trophic Resources
Abstract
Dung beetles play an important role in the sustainability of agroecosystems by providing various ecosystem services. The
spatial distribution of species can be affected by vegetation structure and soil type at a small scale. Our study was conducted
in a cattle ranch in which there were two grassland areas with different types of soil (humid silty clay vs. dry clay) and a
plantation of Eucalyptus L’Hér. (Myrtaceae). The aim of this study was to analyze variations in diversity and structure of
dung beetle assemblages by considering the feeding guilds (coprophagous, necrophagous, and generalists) and functional
groups (paracoprids, telecoprids, and non-nester dwellers) among the three mentioned habitats. Nine pitfall traps baited with
cow dung, horse dung, or carrion were placed simultaneously at each site every two weeks over the course of a year.
Coprophagous species dominated over necrophagous and generalist species in abundance and biomass in each habitat. The
highest species richness occurred in the pasture on humid silty clay soil and the lowest in the Eucalyptus plantation.
Abundance and biomass of paracoprids were highest in the pasture on humid silty clay soil, while non-nester dwellers
dominated in the pasture on dry clay soil and the Eucalyptus plantation. Large paracoprids were almost non-existent in the
pasture with dry clay soil. In the Eucalyptus plantation, the marked reduction in species richness, particularly of telecoprids
and paracoprids, the increase in species dominance, and the absence of rare species were clear indicators of an adversely
affected environment.
Keywords: Scarabaeinae, Aphodiinae, richness, diversity, soil type, Eucalyptus plantation
DOI.org/10.1649/0010-065X-76.3.407
... In addition, compaction induced by exposure of the subsurface horizon could inhibit its burrowing and reproduction ability. Soil compaction has been found to greatly inhibit activities of paracoprid beetles (Canziani and González-Vainer, 2022). ...
... For example, Crematogaster is a predatory arboreal ant preying on other insects such as wasps, termites and grasshoppers (Blaimer, 2020;Richard et al., 2001). Camponotus sp., on the other hand, are omnivorous feeding on a wide range of materials such as plant sap, nectar, honeydew, and small insects (Cannon, 1998). These unique characteristics make ants marginally responsive to land degradation. ...
... Data compiled from the material examined by Cupello & Vaz-de-Mello (2013 and herein, from information provided by colleagues (F. Ocampo and P. G. da Silva, the latter indicated by the collection abbreviations LBEV, MCCR, MCTP, MECB, MHNU, MRGC), and from additional records found in the literature (Blanchard 1846;Martínez 1959;Barattini & Sáenz 1961Cabrera-Walsh & Cordo 1997;Morelli et al. 2002;Sánchez & Genise 2008;Canziani & González-Vainer 2022). Bold denotes places where both species have been recorded. ...
Previously overlooked literature now brought to my attention has resulted in the following nomenclatural conclusions: 1) The species known since 2013 as Gromphas inermis Harold, 1869 must be called G. lacordairii (Oken, 1834), whose original combination was Coprobius lacordairii. Gromphas inermis is a new junior subjective synonym of G. lacordairii; 2) Gromphas was made available by Dejean, in 1836, not Brullé, in 1837; the former, therefore, should be credited with the authorship; and 3) the type species of Gromphas is Coprobius lacordairii Oken, 1834 by original monotypy, not Onitis aerugionosus Perty, 1830 by subsequent monotypy. Also discussed is the publication year of G. jardim Cupello & Vaz-de-Mello, 2015. This leads me to address the problem of zoological works first published in electronic-only versions with their own pagination and which are later reissued integrated into a journal’s volume and repaginated. It is here argued that these two versions – the detached and the volume-integrated ones – should be deemed separate available works, and that new nomenclatural acts can be made available from detached versions. If this is accepted, the later publication of the volume-integrated versions has no bearing on the availability of the earlier detached versions. I also introduce new data on the type series of Onitis aeruginosus (currently, Gromphas aerugionosa) and G. inermis, new specimens of the rare G. jardim, mislabelled specimens of G. amazonica Bates, 1870, and newly discovered specimens of the vanished G. dichroa Blanchard, 1846. The latter include the new record from Santa Catarina state, Brazil. The disappearance of G. dichroa since 1954, including
the possibility that it might be extinct, is discussed.
Dung beetles are of great importance in livestock ecosystems. The utilization of macrocyclic lactones to control cattle parasites has a detrimental effect on the community of dung invertebrates. The objective of this study was to evaluate the attraction of Onthophagus hircus to ivermectin-fortified fecal matter (IFM) under laboratory conditions. Dung beetles primarily detect food through olfaction. To assess odor discrimination behavior, a passive hole-board olfactometer (HBO) was designed. The efficacy of the design was tested through the execution of two control experiments, which measured the attraction (both group and individual) of O. hircus to control fecal matter (CFM) or soil (S). The third experiment was conducted to evaluate individual attraction to IFM. The data were analyzed using descriptive statistics and comparative analyses, and the selection rate was estimated. In both the individual and group control experiences, active individuals were significantly attracted to CFM (46% and 74%, respectively) (p < 0.05 in both cases). Attraction percentages in experiment 3 were: 44% for IFM, 38% for CFM, and 19% for S (p < 0.05). Male and female beetles showed a slight tendency to be attracted to IFM but did not display a significant preference between IFM and CFM (p > 0.05). This study confirmed that an HBO design is a valid approach for testing odor discrimination and assessing the attraction of O. hircus to bovine feces. However, this species demonstrated an inability to differentiate between ivermectin-contaminated and untreated faeces.
The Cañón del Sumidero National Park (PNCS) is a priority area for conservation, but there are few studies on its fauna, which evidences the need for further basic studies to produce adequate knowledge on its biodiversity. This study aimed to determine dung beetle assemblages temporal distribution, trophic preference, and daily activity patterns. We conducted samplings using baited pitfall traps in a PNCS tropical sub deciduous forest remnant, during the dry and rainy seasons between 2014 and 2015. We captured a total of 863 individuals of 20 species, 12 genera, and five tribes of Scarabaeinae. Estimators suggest that we obtained high faunistic representation (> 80%), but species richness is low compared to other regional studies. The community was characterized by a high number of rare species and few dominant species. We captured the greatest richness and abundance during rainy months, however, species composition between seasons did not differ significantly. Trophic preference was mainly generalist and we considered only four species as specialists to tapir dung. We observed a clear segregation between activity hours. Nevertheless, we determined only nine species as specialists (six nocturnal and three diurnal) and two others had generalist habits. The low diversity we found could be influenced by the constant pressure of the urban area and non-native species within the park, which alter the dung beetle assemblages. However, performing samplings for longer periods and using a wider range of resources would help us obtain more robust results and better understand species distribution patterns.
Rarity has long been a question of great interest in a wide range of fields. A method to classify rare species should be simple and easy for different professional groups to learn. Rabinowitz is not only easy-to-follow but also one of the most accepted methods to classify rare species. This study proposes a rarity index (rr) based on Rabinowitz’s scheme. The index operates at the species level. Given a list of n species, the inverse of the geographical range in decimal degree (geographic range index – gri) of the maximum number of species habitats (habitat specificity index – hsi), and the maximum population size anywhere (population size index – psi) were calculated for each species. An average index rr = med(gri + hsi + psi) was calculated for each species from the gri, hsi, and psi indexes. The rr varies from 0 to 1: the closer rr is to 1, the rarer the species. A code in the R language to calculate each proposed measure is provided. The output of this code is a list of species with their respective indices. RR is useful in the ecology and biodiversity conservation fields. This index has the following advantages: (1) it uses three aspects of rarity to gain a synthetic index; (2) the three parameters have equal weights; and (3) it is easily followed by anyone who feels inclined to use it. Some directions on how it might be used are discussed.
The preservation of tropical forests is increasingly at risk, including forests located within human-modified landscapes that retain high conservation value. People modify and interact with these landscapes through a wide range of uses. However, our knowledge of how different forest uses affect biodiversity is limited. Here, we analyse the responses of different taxa to four distinct categories of forest management, namely old-growth forest, Brazil nut extraction areas, reduced impact logging areas, and eucalyptus plantations. Within six independent replicates of each category, we sampled three taxa (fruit-feeding butterflies, dung beetles, and trees) in eastern Amazonia. Forests under moderate use (Brazil nut extraction and reduced-impact logging) had similar, albeit slightly lower, diversity levels relative to old-growth forests, while communities in plantations were significantly less diverse. Only 4%, 20%, and 17%, of the sampled butterfly, dung beetle, and tree species, respectively, were restricted to old-growth forests. This study provides further empirical evidence of the importance of old-growth forest conservation in the context of human-modified landscapes. It also suggests that landscape matrices integrating forest uses at varying intensities are well positioned to reconcile biodiversity conservation with the production of goods that support local livelihoods.
The role of deterministic and stochastic mechanisms in community assembly is a key question in ecology, but little is known about their relative contribution in dung beetle assemblages. Moreover, in human modified landscapes these mechanisms are crucial to understand how biodiversity can be maintained in productive agroecosystems. We explored the assembly mechanisms driving dung beetle assemblages in forests and grazed grassland patches, and assessed the role of dung availability, soil hardness and moisture, elevation and land use heterogeneity as environmental predictors of functional diversity. To determine the underlying assembly mechanisms, we estimated functional diversity metrics (functional richness, evenness and divergence) and their departure from the predicted values by null models. We also used GLMs to assess the influence of environmental variables on functional diversity. In most cases, stochastic processes prevailed in structuring dung beetle assemblages and, consequently, environmental variables were not good predictors of dung beetle functional diversity. However, limiting similarity was found as a secondary mechanism with an effect on dung beetle assemblages in grasslands. Our results highlight the importance of stochastic processes that may reflect a metacommunity dynamic. Therefore, restoring landscape connectivity might be more important than habitat quality for the conservation of these functionally diverse beetle assemblages.
Dung beetles are secondary seed dispersers, incidentally moving many of the seeds defecated by mammals vertically (seed burial) and/or horizontally as they process and relocate dung. Although several studies have quantified this ecological function of dung beetles, very few have followed seed fate until seedling establishment, and most of these have focused on the effects of seed burial. We know very little about the effects of horizontal seed movement by dung beetles, though it is generally assumed that it will affect plant recruitment positively through diminishing seed clumping. The objective of our study was to assess the effects of dung beetle activity on the spatial distribution of seeds and seedlings, and on the probability of seedling establishment. In a tropical rainforest in Mexico we carried out two complementary field experiments for each of two tree species (Bursera simaruba and Poulsenia armata), using seeds experimentally imbedded in pig dung and recording their fate and spatial location over time. For both species, dung beetle activity reduced the spatial clumping of seeds and seedlings; however, it did not increase the probability of seedling establishment. We discuss the context- and species-specificity of the combined effects of horizontal and vertical dispersal of seeds by dung beetles, and the need to quantify long-term seedling fates to more accurately determine the effects of seed movement by dung beetles on plant recruitment.
São Joaquim National Park (SJNP), in southern Brazil, covers large areas of high-altitude grasslands (HAG), which are a conspicuous ecosystem that belongs to the Atlantic Forest domain. Previous studies recorded 6 species of dung beetles (Coleoptera, Scarabaeinae) in SJNP. Dung beetles were sampled using a standardized protocol (baited pitfall traps) at 6 HAG sites in January 2016. In this paper, an annotated list of the dung beetle species sampled in SJNP is presented. This list includes previous literature records and ecological and distributional information of the species. Nine species of Scarabaeinae were collected, including 8 of them newly recorded from SJNP. The dung beetle as-semblages were composed of species having diurnal habits and colorful bodies, and showing a similar proportion of roller–tunneller, and coprophagous–trophic generalist species. New studies could substantially increase the number of dung beetle species in the SJNP.
Primary seed dispersal of many rain-forest seeds occurs through defecation by mammals. Dung beetles are attracted to the defecations and through their dung-processing behaviour these insects change the initial pattern of seed deposition. Final seed deposition patterns, i.e. where and how seeds are deposited after dung beetle activity has taken place, may strongly depend on seed size. In this study we addressed the following question: Do different sizes of seeds have different deposition patterns following dung beetle processing? We conducted a field experiment in lowland Amazonian rain forest in Brazil using 200-g dung-piles containing seed mimics of three sizes: 3.5, 8.6 and 15.5 mm long. Seed deposition condition after dung beetle activity was dependent on seed size. Small seeds were more often buried in beetle tunnels, while medium and large seeds more often remained on the soil surface, either clean or still covered by dung. A low proportion of seeds of all sizes remained on the soil surface covered by loose soil excavated by dung beetles. We speculate that the latter deposition pattern, though not very frequent, might be highly favourable for both seed survival and seedling establishment.
Knowing the biodiversity of dung beetles in agricultural and livestock environments is the basis for understanding the contribution that these organisms make in nutrient cycling and ecosystem functions. The aim of the present study was to investigate the structure of copronecrophagous dung beetle communities inhabiting the main agroecosystems in southern Brazil and correlate the presence of these organisms with soil properties. From December 2012 to April 2013, samples of dung beetles were taken in the municipality of Tubarão, Santa Catarina, Brazil (28° 28’ S; 48° 56’ W) in corn, bean, and sugarcane crops, and in cattle pastures. Beetles were captured in 16 sampling sites, four from each agroecosystem, following a standardized methodology: 10 baited pitfall traps (feces and rotting meat) at a spacing of 50 m with exposure for 48 h. The beetles were identified, weighed, and measured. Soil analyses were performed in order to correlate data on organic matter, texture, macro and micronutrients, and pH with data on the abundance of beetle species using canonical correspondence analysis. A total of 110 individuals belonging to 10 species of dung beetles was found. Twenty-four individuals from seven species (with total biomass of 2.4 g) were found in the corn crop; five individuals from three species (1.8 g) were found in the bean crop; 81 individuals from nine species (30.3 g) were found in cattle pasture areas; and lastly, there were no dung beetles recorded in the sugarcane crop. In areas of cattle grazing, the tunnelers Dichotomius nisus and Trichillum externepunctatum correlated positively with organic matter content, whereas the roller species Canthon chalybaeus correlated positively with soil texture, preferring sandier soils. In corn crop areas, D. nisus was again correlated with organic matter content. Paracoprid dung beetle species were correlated with organic matter content in the soil, and species belonging to the roller functional group were associated with soil texture in the corn crop, preferring sandy soils. Information regarding the relationship of dung beetles with physical-chemical soil properties may be an important strategy for increasing fertility and management of soil conservation in agroecosystems.
The degradation and replacement of native ecosystems affects both their taxonomic and functional biodiversity. However, native species may find a gradient of habitat suitability in different land uses within a region. The aim of this study was to evaluate the effect of land use on the taxonomic and functional diversity of dung beetle assemblages in the southern Atlantic forest of Argentina. Dung beetles were sampled in both the native forest (control) and different land uses (Pine and Yerba mate plantations and cattle pastures) during the 2014 summer, using pitfall traps baited with human feces and rotten meat. Samplings were taken from 20 different sites, with five replicates of each land use and the native forest (100 pitfall traps in total). A total of 1699 beetles of 27 species were captured. Canthon quinquemaculatus, Canthon conformis and Dichotomius sericeus were the most abundant species. Cattle pastures were the land use most negatively affected in their taxonomic and functional diversity, particularly large paracoprid dung beetles. Pine plantations maintained their taxonomic and functional diversity in relation to the native forest and Yerba mate plantations showed, in general, an intermediate situation. Microclimatic conditions (average temperature and humidity and maximum temperature) were correlated with functional diversity (the proportion of large paracoprid dung beetles decreased with increasing temperature) and are probably good predictors to explain the observed patterns of functional diversity of dung beetles. The development of sustainable production systems that preserve the native biodiversity requires the conservation of key components from the ecological niche of native species, especially microclimatic conditions.
iNEXT (iNterpolation and EXTrapolation) Online is the R-based interactive online version of iNEXT available via the link https://chao.shinyapps.io/iNEXTOnline/ or http://chao.stat.nthu.edu.tw/wordpress/software_download/. Clicking these links, you will be directed to the online interface window. Users do not need to learn/understand R to run iNEXT Online. The interactive web application was built using the Shiny (a web application framework). iNEXT features two statistical analyses (non-asymptotic and asymptotic) for species diversity based on Hill numbers: (1) A non-asymptotic approach based on interpolation and extrapolation iNEXT computes the estimated diversities for standardized samples with a common sample size or sample completeness. This approach aims to compare diversity estimates for equally-large (with a common sample size) or equally-complete (with a common sample coverage) samples; it is based on the seamless rarefaction and extrapolation sampling curves of Hill numbers for q = 0, 1 and 2. See Colwell et al. (2012), Chao and Jost (2012) and Chao et al. (2014) for pertinent background and methods. (2) An asymptotic approach to infer asymptotic diversity iNEXT computes the estimated asymptotic diversity profiles. It is based on statistical estimation of the true Hill number of any order q ≥ 0; see Chao and Jost (2015) for the statistical estimation detail.
The aim of the present study was to evaluate the daily activity and habitat associations of dung beetles, to examine their seasonal variation and to determine which species are dominant in a region of Brazilian Atlantic Forest. Sampling was performed with pitfall traps baited with carrion and human excrement. Dung beetles were more abundant in open habitat during the day, and in closed habitat at dusk. No difference was found in the abundance and period of activity between seasons. Species richness varied with seasonality in different habitats. Greatest species richness was found at dusk. No significant association was found between body size and period of activity. Segregation of the dung beetle community was found to be associated with the period of activity.
Hill numbers (or the effective number of species) have been increasingly used to quantify the species/taxonomic diversity of an assemblage. The sample‐size‐ and coverage‐based integrations of rarefaction (interpolation) and extrapolation (prediction) of H ill numbers represent a unified standardization method for quantifying and comparing species diversity across multiple assemblages.
We briefly review the conceptual background of H ill numbers along with two approaches to standardization. We present an R package iNEXT (i N terpolation/ EXT rapolation) which provides simple functions to compute and plot the seamless rarefaction and extrapolation sampling curves for the three most widely used members of the H ill number family (species richness, S hannon diversity and S impson diversity). Two types of biodiversity data are allowed: individual‐based abundance data and sampling‐unit‐based incidence data.
Several applications of the iNEXT packages are reviewed: (i) Non‐asymptotic analysis: comparison of diversity estimates for equally large or equally complete samples. (ii) Asymptotic analysis: comparison of estimated asymptotic or true diversities. (iii) Assessment of sample completeness (sample coverage) across multiple samples. (iv) Comparison of estimated point diversities for a specified sample size or a specified level of sample coverage.
Two examples are demonstrated, using the data (one for abundance data and the other for incidence data) included in the package, to illustrate all R functions and graphical displays.
Aim
In this study, we investigate whether anthropogenic land use and habitat fragmentation lead to a process of either homogenization (decreasing spatial replacement and increasing nestedness) or divergence (increasing spatial replacement and decreasing nestedness) of dung beetle assemblages in edge‐affected habitats.
Location
A fragmented landscape of the Atlantic forest of north‐east Brazil.
Methods
We investigate the extent to which beta diversity of dung beetle assemblages varies in edge‐affected habitats at different spatial scales (i.e. traps along an interior–exterior nonlinear gradient, within and among habitats). We compare species replacement and nestedness of dung beetle assemblages using (1) multiple dissimilarity measures accounting for compositional heterogeneity across forest (i.e. forest edges, core primary forest areas and small fragments) and matrix habitats (i.e. sugar cane plantations and pastures) and (2) distance matrices accounting for the multivariate structure of dissimilarity.
Results
(1) Each habitat supported a distinct dung beetle assemblage; (2) there was a strong influence of anthropogenic land use and fragmentation‐related effects on dung beetle β‐diversity, with species replacements increasing in edge‐affected and matrix habitats providing support for the divergence hypothesis at all spatial scales; (3) edge effects enhanced species replacement across assemblages; (4) dung beetle assemblages were not randomly distributed, with habitat type leading to a strongly nested pattern of species composition; and (5) both dung beetle replacement and nestedness were not correlated with geographic distance, whereby neighbouring sites were not necessarily more similar in their community composition.
Main conclusions
Species replacement is strongly influenced by habitat configuration and β‐diversity increases in edge‐affected habitats. Accordingly, anthropogenic land use and habitat fragmentation clearly promote community‐level taxonomic divergence in human‐modified landscapes. Landscape‐scale divergence likely results from a non‐random distribution of both forest‐dependent and disturbance‐adapted species across all habitats, which are in marked contrast in terms of suitability.
This study aimed to describe the structure functional guilds of dung beetles (Scarabaeidae: Scarabaeinae) and analyze the effects of the concentration of clay in soil in this structure. The studies were developed in the north and southwest in the state of Mato Grosso. The dung beetles and soil samples were collected in the north (PPBio) and southwest (22 farms reserve) in Mato Grosso. The dung beetle were captured with pitfall traps baited with human feces exposed for 48 hours. In the north region were utilized 85 traps and 132 in the southwest. Both regions, the results showed similarity at guild structure, with paracoprids dominance, followed by telecoprids and endocoprids. Which demonstrates consistency with the Neotropical pattern. Which emphasizes the theory of the existence of a deterministic taxonomic and functional structure for the subsamples in this region. The concentration of clay showed different effects for both regions studied. To the north caused the reduction in the abundance of endocoprids and small telecoprids and reduced the richness of large paracoprids. In the southwest region had mainly influences on reducing of small paracoprids, the increase of small telecoprids and also the large endocoprids. In micro-habitat scale, concentration of clay in the soil showed an important structural element of the functional guilds of dung beetles. The Guilds of the small paracoprids and small telecoprids were most affected by the variation of soil granulometry. © 2015, Universidade Federal de Uberlandia. All rights reserved.
Community structure is driven by mechanisms linked to environmental, spatial and temporal processes, which have been successfully addressed using metacommunity framework. The relative importance of processes shaping community structure can be identified using several different approaches. Two approaches that are increasingly being used are functional diversity and community deconstruction. Functional diversity is measured using various indices that incorporate distinct community attributes. Community deconstruction is a way to disentangle species responses to ecological processes by grouping species with similar traits. We used these two approaches to determine whether they are improvements over traditional measures (e.g., species composition, abundance, biomass) for identification of the main processes driving dung beetle (Scarabaeinae) community structure in a fragmented mainland-island landscape in southern Brazilian Atlantic Forest. We sampled five sites in each of four large forest areas, two on the mainland and two on the island. Sampling was performed in 2012 and 2013. We collected abundance and biomass data from 100 sampling points distributed over 20 sampling sites. We studied environmental, spatial and temporal effects on dung beetle community across three spatial scales, i.e., between sites, between areas and mainland-island. The γ-diversity based on species abundance was mainly attributed to β-diversity as a consequence of the increase in mean α-and β-diversity between areas. Variation partitioning on abundance, biomass and functional diversity showed scale-dependence of processes structuring dung beetle metacommunities. We identified two major groups of responses among 17 functional groups. In general, environmental filters were important at both local and regional scales. Spatial factors were important at the intermediate scale. Our study supports the notion of scale-dependence of environmental, spatial and temporal processes in the distribution and functional organization of Scarabaeinae beetles. We conclude that functional diversity may be used as a complementary approach to traditional measures, and that community deconstruction allows sufficient disentangling of responses of different trait-based groups.
Quantifying and assessing changes in biological diversity are central aspects of many ecological studies, yet accurate methods of estimating biological diversity from sampling data have been elusive. Hill numbers, or the effective number of species, are increasingly used to characterize the taxonomic, phylogenetic, or functional diversity of an assemblage. However, empirical estimates of Hill numbers, including species richness, tend to be an increasing function of sampling effort and, thus, tend to increase with sample completeness. Integrated curves based on sampling theory that smoothly link rarefaction (interpolation) and prediction (extrapolation) standardize samples on the basis of sample size or sample completeness and facilitate the comparison of biodiversity data. Here we extended previous rarefaction and extrapolation models for species richness (Hill number qD, where q = 0) to measures of taxon diversity incorporating relative abundance (i.e., for any Hill number qD, q > 0) and present a unified approach for both individual-based (abundance) data and samplebased (incidence) data. Using this unified sampling framework, we derive both theoretical formulas and analytic estimators for seamless rarefaction and extrapolation based on Hill numbers. Detailed examples are provided for the first three Hill numbers: q = 0 (species richness), q = 1 (the exponential of Shannon's entropy index), and q = 2 (the inverse of Simpson's concentration index). We developed a bootstrap method for constructing confidence intervals around Hill numbers, facilitating the comparison of multiple assemblages of both rarefied and extrapolated samples. The proposed estimators are accurate for both rarefaction and short-range extrapolation. For long-range extrapolation, the performance of the estimators depends on both the value of q and on the extrapolation range. We tested our methods on simulated data generated from species abundance models and on data from large species inventories. We also illustrate the formulas and estimators using empirical data sets from biodiversity surveys of temperate forest spiders and tropical ants.
The compositional complexity of an assemblage is not expressible as a single number; standard measures such as diversities (Hill numbers) and entropies (Rényi entropies and Tsallis entropies) vary in their order q which determines the measures' emphasis on rare or common species. Ranking and comparing assemblages depend on the choice of q . Rather than selecting one or a few measures to describe an assemblage, it is preferable to convey the complete story by presenting a continuous profile, a plot of diversity or entropy as a function of q ≥ 0. This makes it easy to visually compare the compositional complexities of multiple assemblages and to judge the evenness of the relative abundance distributions of the assemblages. In practice, the profile is plotted for all values of q from 0 to q = 3 or 4 (beyond which it generally changes little).
These profiles are usually generated by substituting species sample proportions into the complexity measures. However, this empirical approach typically underestimates the true profile for low values of q , because samples usually miss some of the assemblage's species due to under‐sampling. Although bias‐reduction methods exist for individual measures of order q = 0, 1 and 2, there has been no analytic method that unifies these bias‐corrected estimates into a continuous profile.
For incomplete sampling data, this work proposes a novel analytic method to obtain accurate, continuous, low‐bias diversity and entropy profiles with focus on low orders of q (0 ≤ q ≤ 3). Our approach is based on reformulating the diversity and entropy of any order q in terms of the successive discovery rates of new species with respect to sample size, that is the successive slopes of the species accumulation curve. A bootstrap method is applied to obtain approximate variances of our proposed profiles and to construct the associated confidence intervals.
Extensive simulations from theoretical models and real surveys show that the proposed profiles greatly reduce under‐sampling bias and have substantially lower bias and mean‐squared error than the empirical profile, especially for q ≤ 1. Our method is also extended to deal with incidence data.
Mammal feces are the primary food and nesting resource for the majority of dung beetle species, and larval development depends on the quantity and quality of that resource. Physiological necessities, competitive interactions, and resource sharing are common and suggest that dung beetles may show preferences for feces of greater nutritional quality, which may in turn impact beetle assemblages and community structure. This study investigated whether attractiveness of dung beetles to different resource (feces) types varies depending on mammal trophic guild and associated nutritional content. This study was conducted in Atlantic Forest fragments in the Parque Estadual da Serra do Tabuleiro, Santa Catarina, Brazil. To evaluate attractiveness, the feces of the carnivore Puma concolor, the omnivores Cerdocyon thous and Sapajus nigritus, and the herbivore Tapirus terrestris were utilized as bait. Dung was collected from zoo animals fed a standard diet. Sampling was performed in triplicate in five areas in the summer of 2013. Four pitfall traps were established in each area, and each trap was baited with one type of mammal feces. Food preference of the species was analyzed by calculating Rodgers' index for cafeteria-type experiments. In total, 426 individuals from 17 species were collected. Rodgers' index showed that omnivorous mammal feces (C. thous) were most attractive to all dung beetle species, although it is known that dung beetles are commonly opportunistic with respect to search for and allocation of food resources. These results suggest that mammal loss could alter competitive interactions between dung beetles.
© The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.
The 27 Aphodiinae (Coleoptera: Scarabaeidae) species that occur in southern South America are reviewed. This study region consists of the southern parts of Argentina and Chile including the Central Chilean, Patagonian, and Subantarctic biogeographical provinces. Keys, illustrations, and distributional records with maps for all species are presented. Seventeen species are native to southern South America, nine species are introduced, and the status of one species could not be determined due to a lack of study material. Nine of the 17 native species are endemic to southern South America, and the relationship between these endemic species and similar Australian groups is discussed. A number of classification and nomenclatural changes are made. Paranimbus Schmidt and Pseudopodotenus Dellacasa are considered to subgenera of Podotenus Schmidt. As a result, the following new combinations are created: Podotenus (Paranimbus) longitarsis (Harold), Podotenus (Paranimbus) penai (Petrovitz), Podotenus (Paranimbus) peruanus (Erichson), Podotenus (Paranimbus) zoiai (Dellacasa), and Podotenus (Pseudopodotenus) fulviventris (Fairmaire and Germain). Ataenius chilensis (Solier) is removed from synonymy with Ataenius gracilis (Melsheimer) and is considered a valid species. Ataenius modestus Schmidt is synonymized under Ataenius chilensis (Solier). Psammobius indefensus Schmidt is transferred to the genus Leiopsammodius and Leiopsammodius chilensis Rakovic is placed in synonymy with this name. Lectotypes are designated for the following names: Aphodius chilensis Solier (now Ataenius chilensis), Aphodius reflexus Schmidt (now Orodaliscoides reflexus), Ataenius modestus (now a synonym of Ataenius chilensis), and Psammobius indefensus Schmidt (now Leiopsammodius indefensus). A neotype is designated for Aphodius angustus Philippi and Philippi, a synonym of Pleurophorus caesus (Panzer). Records considered to be erroneous for several Aphodiinae species in southern South America are also discussed.
Dung beetle assemblages (Coleoptera, Scarabaeinae) in Atlantic forest fragments in southern Brazil. The beetles of the subfamily Scarabaeinae are important organisms that participate in the cycle of decomposition, especially in tropical ecosystems. Most species feed on feces (dung) or carcasses (carrion) and are associated with animals that produce their food resources. Dung beetles are divided into three functional groups: rollers, tunnelers and dwellers. This present work aims to study the diversity of dung beetle communities inhabiting fragments of the Atlantic Forest, with the purpose of describing the ecology of the species in southern Brazil. This study was conducted in the region of Campos Novos, in Santa Catarina, where twenty sites of Atlantic forest fragments were sampled. Samplings of dung beetles were conducted using 200 pitfall traps, of which 100 were baited with human feces and another 100 with carrion. Size and environmental complexity were also measured for each forest fragment. A total of 1,502 dung beetles, belonging to six tribes, 12 genera and 33 species, were collected. Results of the Levin's index of niche breadth indicated that 11 species were categorized as being coprophagous, ten as generalists, and two as necrophagous. Most species are tunnelers (19), nine of rollers and four of dwellers. The great diversity of Scarabaeinae in the region of Campos Novos, including several rare species, adds important data to the Scarabaeinae fauna in the central-western region of Santa Catarina. It may also help choosing priority areas for conservation in the region, where human impact, with large areas of monoculture, increasingly threatens the fragments of Mixed Ombrophilous Forest.
The dung beetles are extremely important as decomposers, natural enemies of coprobiont pests and environmental indicators. They have great benefit to the livestock agroecosystems, acting in the destruction of fecal masses and carcasses of animals, helping with the natural biological control of parasites of cattle that develop in these materials. However, no research was done in the country region of Rio Grande do Sul about the response of dung beetles communitys to a natural forest and native pasture ecotone that occurs there. Thus, a survey of dung beetles occurring in that ecotone was conducted on the Rural Campus of the Universidade in the country region, Bagé, on October, 2007. Eighteen pitfall traps were utilized to collect the
dung beetles, and were distributed in three parallel transects, with nine in each environment, baited with fresh fecal mass and decomposed liver of cattle. Three collections with hopes of a 48h and one after 120h were conducted. Were captured 250 dung beetles of 16 species, and the species more abundant were Canthon rutilans Laporte, 1840 (131 individuals) and Ateuchus aff. robustus, Harold, 1868 (39 individuals). The forest area showed higher number of species and individuals than the native pasture area and edge area. Nevertheless, the border area showed higher rates of diversity than the other ecosystems. The presence of border had an effect so pronounced as the environment type on the abundance and distribution of the collected dung beetles species. New specie was recorded for the city of Bagé.
There are few studies on the fauna of Scarabaeinae in Rio Grande do Sul, Brazil. The aim of this study was to determine species of the Scarabaeinae in areas of Eragrostis plana Nees and Eucalyptus spp., 2 exotic habitats originally occupied by native grasslands, in the town of Bagé, Rio Grande do Sul, Brazil; and to compare them with the richness found in other ecosystems at the same location. Beetles were collected with the use of pitfall traps with various kinds of bait and without bait, from Sept. to Dec. 2006. In total, 264 beetles belonging to 5 tribes, 7 genera, and 13 species were captured. Onthophagus aff. hirculus Mannerheim, Canthon lividus Blanchard, C. bispinus (Germar), and C. podagricus Harold were the most abundant species. A comparison of the richness of the studied Scarabaeinae in this region showed that the richness found in the exotic habitats investigated was lower. These habitats seem to have influenced the Scarabaeinae fauna, giving support only to common species native to the region with generalist eating habits.
The accurate sampling of communities is vital to any investigation of ecological processes and biodiversity. Dung beetles have emerged as a widely used focal taxon in environmental studies and can be sampled quickly and inexpensively using baited pitfalls. Although there is now a wealth of available data on dung beetle communities from around the world, there is a lack of standardisation between sampling protocols for accurately sampling dung beetle communities. In particular, bait choice is often led by the idiosyncrasies of the researcher, logistic problems and the dung sources available, which leads to difficulties for inter-study comparisons. In general, human dung is the preferred choice, however, it is often in short supply, which can severely limit sampling effort. By contrast, pigs may produce up to 20 times the volume. We tested the ability of human and pig dung to attract a primary forest dung beetle assemblage, as well as three mixes of the two baits in different proportions. Analyses focussed on the comparability of sampling with pig or human-pig dung mixes with studies that have sampled using human dung. There were no significant differences between richness and abundance sampled by each bait. The assemblages sampled were remarkably consistent across baits, and ordination analyses showed that the assemblages sampled by mixed dung baits were not significantly different from that captured by pure human dung, with the assemblages sampled by 10% and 90% pig mixes structurally most similar to assemblages sampled by human dung. We suggest that a 10:90 human:pig ratio, or similar, is an ideal compromise between sampling efficiency, inter-study comparability and the availability of large quantities of bait for sampling Amazonian dung beetles. Assessing the comparability of assemblage samples collected using different baits represents an important step to facilitating large-scale meta-analyses of dung beetle assemblages collected using non-standard methodology.
This study provides data about the Scarabaeinae fauna that occurs in a eucalyptus plantation inserted in an originally open area, describing which are able to establish themselves in this introduced and shaded environment. The survey was carried in an area of eucalyptus monoculture using flight intercept and pitfall traps baited with human feces, rotten banana and carcass, from December 2005 to November 2006. Twenty-eight species were collected, belonging to 11 genera. Of these 28 species, 11 have been previously recorded in grassland and native forest environments of the region, 11 only in grasslands, two were exclusive of eucalyptus plantations and four were not identified at the specific level, which did not allow the achievement of more information on these species in the natural ecosystems of the region. The results showed that species that occur in eucalyptus are habitat generalists, have preference for shaded environments and/or are tourist species. This, however, is one of the few surveys performed in the region. Therefore, additional studies are necessary to obtain more information about the distribution and response of dung beetles to natural and anthropogenic ecosystems of the region.
Although there is increasing interest in the effects of habitat disturbance on community attributes and the potential consequences for ecosystem functioning, objective approaches linking biodiversity loss to functional loss are uncommon. The objectives of this study were to implement simultaneous assessment of community attributes (richness, abundance and biomass, each calculated for total-beetle assemblages as well as small- and large-beetle assemblages) and three ecological functions of dung beetles (dung removal, soil perturbation and secondary seed dispersal), to compare the effects of habitat disturbance on both sets of response variables, and their relations. We studied dung beetle community attributes and functions in five land-use systems representing a disturbance gradient in the Brazilian Amazon: primary forest, secondary forest, agroforestry, agriculture and pasture. All response variables were affected negatively by the intensification of habitat disturbance regimes, but community attributes and ecological functions did not follow the same pattern of decline. A hierarchical partitioning analysis showed that, although all community attributes had a significant effect on the three ecological functions (except the abundance of small beetles on all three ecological functions and the biomass of small beetles on secondary dispersal of large seed mimics), species richness and abundance of large beetles were the community attributes with the highest explanatory value. Our results show the importance of measuring ecological function empirically instead of deducing it from community metrics.
Dung beetles attracted to howler monkey (Alouatta palliata) and coati (Nasua narica) dung were studied for an annual cycle in the tropical rain forest of Los Tuxtlas, Mexico. Pitfall traps set for 24 h month−1 captured 1567 dung beetles of 21 species. The species Canlhidium martinto, Deltochilum pseudoparile and Canthon femoralis accounted for 62% of all individuals captured. While species overlap was high (> 80%) between diurnal and nocturnal samples and between howler monkey and coati dung baits, coati dung attracted species such as C. martinezi, D. pseudoparile and Onthophagus rhinolophus while species such as C. femoralis and Copris laeviceps were numerically dominant at howler monkey dung. Thirteen non-ball rolling dung beetle species and eight ball-rolling species accounted for 43% and for 57% of all beetles captured respectively. Dung beetles were present and active in all months of the year, but occurred in higher numbers between the months of March and October, when temperatures were higher. Relative abundance of howler monkey and coati dung in the rain forest of Los Tuxtlas was estimated at 11.2 g (fresh weight) ha−1 day−1 and at 13.0 g ha−1 day−1 respectively, a seemingly low amount for the large number of scarabs attracted to the dung.
In this study, performed in a remnant of Brazilian Atlantic Forest, three types of dung from animals with distinct alimentary habits were utilized, in order to verify possible differences of attractivity of these dungs to the Scarabaeinae and the influence of seasonality in the attractivity. Three habitats were sampled: edge, clearing and forest core, each with 40 pitfall traps. A total of 2,137 beetles were collected from August 2005 to July 2006. Canthidium sp. 1 (43%) and Dichotomius sericeus (41%) were the most abundant species. From the total number of beetles collected, 80.5% were attracted to human dung, 11% to jaguar dung, 7.8% to waterbuck dung and 0.7% to the control. The species Canthidium sp.1, Canthidium sp. 2, Ateuchus sp., Canthon nigripenne, Canthonella sp. and D. sericeus came to all three bait types. Eight species were found in the baits with human dung, where Canthidium sp.1 (49%) and D. sericeus (39%) were the most common. A significant difference in attractiveness of the different baits was observed; the highest abundance found in traps baited with human dung (F = 36.59; g.l. = 3; p < 0.0001). A significant difference in richness was observed between rainy and dry seasons (F = 12.29; g.l. = 1; p < 0.001), the highest richness found in the dry season.
Regional biogeographical patterns result from a complex combination across habitat, climate and environmental variables. Biotic and abiotic variables strongly influence the diversity and spatial distribution pattterns. However, very few studies analyse the close interaction and effect of environmental variables on diversity at fine spatiotemporal scales. In this study, we evaluated the influence of soil type, vegetation cover and temperature on species diversity and functional structure of dung beetle assemblages. Dung beetle species were sampled
using pitfall traps baited with cattle dung from sandy and clay soils in open woodland and closed canopy areas
in Mkhuze Game Reserve, KwaZulu-Natal, South Africa. We performed a PERMANOVA, a PERMDISP and
an NMDS to analyse differences in species composition between soil and vegetation cover types. To test the
effect of environmental variables on species richness and abundance, we performed a generalised least squares
model. Lastly, we searched for nodes using a bipartite analysis to evaluate network’s potential modularity. We
collected 1439 specimens comprising 27 species and 13 genera. Species composition differed between environmental variables. Soil type was the most important driver for changes in dung beetle species composition. Species richness and abundance were influenced by the interaction between soil type and vegetation cover. The combination of microenvironmental preferences potentially influenced the dung beetle assemblage diversity and
functional structure. Combining all these preferences may act as a dilution mechanism of interspecific competition in saturated habitat conditions, reducing the number of species that potentially interact and generating a
modular network structure of the assemblage.
1. Dung beetles are an important group of insects that use excrement for feeding and reproductive purposes. The interest of the scientific community in dung beetles is highlighted by the increasing number of investigations that use them as the focal group.
2. In the last few years, several studies have used dung beetles as bioindicators and to study ‘biodiversity-ecosystem functioning relationships’ using functional traits. One of the most widely used functional traits in dung beetle studies is their reproductive behaviour.
3. In order to evaluate the use of relevant terminology regarding dung beetle nesting behaviour I analysed 1143 articles published between 1969 and 2020.
4. The analysis brought to light the following four broad issues regarding dung beetle functional groups: (i) the interchangeable use of terms; (ii) overgeneralizations; (iii) the equating of nesting and trophic behaviour and (iv) misspellings. After reviewing these issues, I propose a solution.
Studies addressing the temporal changes of ecological communities within fragmented forests transformed into natural protected areas are urgently needed. The creation of the Los Tuxtlas Biosphere Reserve (LTBR) in 1998 stopped the deforestation process of the northernmost tropical rainforest of the Neotropical region, allowing the analysis of the long-term effects on native communities after the halting of habitat fragmentation. We compared the diversity of dung beetles in 11 forest fragments and eight pastures in the LTBR between two periods: 1999–2000, the early years after the creation of the LTBR; and 2016–2017, i.e., 17 years later. Species richness and abundance of dung beetles were similar in both periods, being higher in forest fragments than in pastures; however, the dominant species were different in each period in both forest fragments and pastures. The number of habitat indicator species increased in 2016–2017 compared to 1999–2000, with a high species diversity of forest indicators relative to pasture indicators at both periods. Alpha and gamma diversities were lower in 1999–2000 than in 2016–2017. Beta-diversity at the spatial level was strongly driven by species turnover, which was higher in pastures than in forest fragments. All functional groups (dwellers, rollers, and tunnellers) showed higher abundances in forest fragments than in pastures in both 1999–2000 and 2016–2017 periods. Our results suggest that stopping the fragmentation process in the LTBR has allowed the survival of native dung beetle assemblages, which are undergoing a recovery process of their populations and ecological functions over the years.
1. Greenhouse gas (GHG) emissions from livestock contribute significantly to global warming, and a reduction of this source of emissions is crucial in achieving the goal of mitigating global warming.
2. CO 2 and CH 4 emissions from dung pats were analysed by means of a mesocosm experiment in a Mediterranean ecosystem. The experiment consisted of a total of 30 mesocosms distributed across three treatments: a well‐preserved, undisturbed dung beetle assemblage associated with organic livestock; a dung beetle assemblage that was impoverished as a result of the long‐term use of veterinary medical products; and a control treatment without dung beetles.
3. Corrections related to insect respiration allow researchers to provide more precise measurements of CO 2 emissions from dung, especially in the initial and final phases of dung exposure, when the percentage of CO 2 emitted by dung beetles can become greater than the emissions from the dung pats themselves.
4. The effects of dung beetles on CO 2 and CH 4 emissions are much more accentuated in warm‐temperate conditions than in northern temperate areas previously studied. Mediterranean assemblages remove and spread dung faster and more effectively than do northern dung beetle assemblages characterised by a lower functional richness and beetle abundance and biomass.
5. From a livestock management viewpoint, mesocosms representing areas with impoverished dung beetle assemblages, due to the long‐term use of veterinary medical products, such as ivermectin, emitted 1.6‐ and 2.8‐fold higher total CO 2 and CH 4 , respectively, than mesocosms mimicking sites with untreated livestock.
Dung beetles have been widely used as bioindicators of environmental quality. Here, we assessed the influence of land use and seasonality on patterns of species richness and abundance of dung beetles in northeastern Brazil. Dung beetles were sampled in five different land uses (cassava, eucalyptus, alley cropping, young fallows and old fallows) in the dry and rainy seasons, using pitfall traps baited with fresh cow manure. Seasonality strongly influenced the dung beetle assemblage with a higher number of species and individuals being collected during the rainy season. Species richness was influenced by land use only in the rainy period. Additionally, except for eucalyptus, all land uses supported high dung beetle diversity during the rainy season. We conclude that seasonality and land use should be taken into consideration in bioindication studies using dung beetles since species richness and abundance vary widely depending on the period of the year and on the habitat.
In grazed ecosystems, coprophagous beetles are known to play an important role in nutrient cycling, but interactions between species identity and dung beetle abundance on soil processes remain unclear. We conducted an outdoor mesocosm experiment to investigate the effects of three dung beetle species at four levels of abundance on dung incorporation into the soil. In addition we assessed indirect effects of dung beetle activity on leaf litter decomposition by microorganisms in soil. Both dung removal and leaf litter mass loss were positively correlated with initial dung beetle biomass and beetle abundance across species. However, the magnitude of beetle-induced increases in litter mass loss was very small compared to the magnitude of beetle effects on dung removal. Beetle effects on dung removal and litter decomposition also showed significant abundance  species interactions, with strongest responses observed for Colobopterus erraticus Linnaeus. Our findings highlight the importance of interactive effects between species identity and abundance on dung removal and provide the first demonstration of indirect dung beetle effects on leaf litter decomposition in soil.
1. The DEFRA ecosystem services framework was implemented in an entomological context to provide preliminary estimates of the economic value of four key ecosystem service benefits delivered by dung beetles ( C oleoptera: S carabaeidae, G eotrupidae) to the U.K. cattle industry and individual cattle farmers. These benefits included (i) reduced pest flies; (ii) reduced gastrointestinal parasites; (iii) reduced pasture fouling and (iv) increased soil nutrients.
2. A mesocosm experiment was carried out to quantify the impacts of anthelmintic treatment on dung removal by dung beetles when (i) cattle were excreting anthelmintics (which affect dung beetles) in a sufficient concentration to impact dung beetles and (ii) when cattle were not excreting dung containing anthelmintics (which affect dung beetles) in a sufficient concentration to impact dung beetles.
3. Inferring from our mesocosm experiment and existing data, the value of the benefits of dung beetles under current farming practices (and current anthelmintic usage) was estimated. We estimated the potential economic benefits if dung beetles were protected (i) under all entry‐level agri‐environment schemes; (ii) under organic schemes; or (iii) if farmers stopped treating adult cattle with anthelmintics during the grazing season.
4. While these estimates are preliminary, and should not be treated as definitive values, we suggest that dung beetles may be currently saving the U.K. cattle industry c. £367 million each year: c . £354 million in conventional systems and c. £13 million in organic systems. Annual benefits per cow are greater in organic systems (£43.47) compared with conventional systems (£37.42).
5. Protecting dung beetles under agri‐environment schemes could save the U.K. cattle industry an additional £40.2 million year ⁻¹ (£4.36 per cow), while protecting dung beetles under organic schemes could save £378 k year ⁻¹ (£1.26 per cow). The cessation of, largely unnecessary, treatment of adult cattle with anthelmintics could save the U.K. cattle industry an additional £6.2 million year ⁻¹ (£1.40 per cow) in addition to savings on the anthelmintics themselves.
6. These estimates are based on a large number of underlying assumptions and, thus, may be overestimating or underestimating the economic value of ecosystem services delivered by dung beetles.
7. The potential for using the DEFRA ecosystem services framework in an entomological context is highlighted. These estimates emphasise the contribution of dung beetles as key E cosystem S ervice P roviders ( ESP 's) within the U.K. cattle sector and, by extension, emphasise the importance of valuing supporting ecosystem services derived from invertebrates.
Observational evidence suggests that burial of faeces by dung beetles negatively influences the transmission of directly transmitted gastrointestinal helminths. However, the mechanistic basis for these interactions is poorly characterised, limiting our ability to understand relationships between beetle community composition and helminth transmission. We demonstrate that beetle body size and sex significantly impact tunnel depth, a key variable affecting parasite survival. Additionally, high parasite loads reduce the depth of beetle faeces burial, suggesting that the local prevalence of parasites infecting beetles may impact beetle ecosystem function. Our study represents a first step towards a mechanistic understanding of a potentially epidemiologically relevant ecosystem function.
Copyright © 2014. Published by Elsevier Ltd.
Coprophilous beetles represent an abundant and rich group with critical importance in the functioning of terrestrial ecosystems. Most coprophagous beetles have a stenotopic distribution in relation to vegetation types. Because of this, they are usually very sensitive to environmental changes and are considered well suited as bioindicator organisms. The aim of this study was to analyze variations in coprophilous beetle assemblages in natural and anthropogenic habitats. Coprophilous beetle communities were sampled monthly for 1 year using pitfall traps baited with cow dung, in native xeric upland forests, 15-years-old plantations of Pinus elliottii and pastures in Sierra de Minas, Lavalleja, Uruguay. A total of 7,436 beetles were caught and identified to species or morphospecies level. The most abundant families were Aphodiidae, Scarabaeidae, and Staphylinidae. Differences in species richness, abundance, Shannon index, evenness, and dominance were detected between habitats. Abundances of most frequent families were significantly higher in both kinds of forests. Species richness and diversity of Aphodiidae and Staphylinidae were higher in forests, while Scarabaeidae showed the highest richness and diversity in pine plantations. Species composition significantly differed between habitats. Uroxys terminalis Waterhouse and Ataenius perforatus Harold typified the assemblages in native forests and pine plantations and also discriminated both communities because of their differential pattern of abundance between habitats. Typifying species in pastures were Onthophagus hirculus, Ateuchus robustus (Harold), and Ataenius platensis Blanchard. Habitat type had a strong effect on the coprophilous beetle community structure and composition.
The aim of this study was to investigate the attractiveness of different types of bait to the Scarabaeinae. Scarabaeinae fauna was sampled using pitfall traps in 3 forest fragments of Santa Maria, Rio Grande do Sul, Brazil, between May 2009 and Apr. 2010. Each habitat received 27 traps placed on 3 transects, each containing 3 sets of 3 traps, respectively baited with human excrement, rotten meat, and rotten banana. Of the total number of species and individuals collected, 33 species and 75.02% of individuals were attracted to human excrement, 29 species and 20.26% of individuals to meat, and only 25 species and 4.72% of individuals to the banana. Kruskal-Wallis tests showed significant statistical differences among the mean species richness (H = 20.65, d.f. = 2, p < 0.01) and abundance (H = 21.56, d.f. = 2, p < 0.01) of beetles attracted to each bait type. An ordination analysis showed the formation of different groups according to feeding habits and trophic niche overlap. According to Levins' index, 14 species were coprophagous, 13 were generalists, and 2 necrophagous. Differences found occurred due to the great change in dung beetle assemblages from each type of baited trap during the study period. In this study, human feces was the most attractive bait, differing significantly from carrion and rotten banana in both species richness and abundance of the Scarabaeinae.
The effect of the dung beetle, Onthophagus lenzii Harold, on the decomposition of cow dung was studied with special reference to the relationship between microbial populations and N mineralization in residual cow dung, dung balls and soil beneath the dung. Two ammonification processes in the decomposition of cow dung were noted. Readily-decomposable organic N in the cow dung mineralized rapidly during the first 5 days, regardless of dung beetle activity. After 15 days, dung beetles accelerated or initiated another ammonification process in residual cow dung and dung balls. Dung beetles accelerated nitrification and fungal growth in residual dung and dung balls by producing aerobic conditions through a rapid decrease in moisture content. Organic N in cow dung fragments, particularly that buried in the upper part of the underlying soil by beetles, was mineralized and simultaneously nitrified. However, a small amount of inorganic N in cow dung diffused down to the underlying soil when dung beetles were absent. Microbial numbers in the soil were highly correlated to the organic matter concentration of the soil.
Comparative analyses that link information on species' traits, environmental change, and organism response have rarely identified unambiguous trait correlates of vulnerability. We tested if species' traits could predict local-scale changes in dung beetle population response to three levels of forest conversion intensity within and across two biogeographic regions (the Neotropics and Afro-Eurasian tropics). We combined biodiversity surveys, a global molecular phylogeny, and information on three species' traits hypothesized to influence vulnerability to forest conversion to examine (1) the consistency of beetle population response across regions, (2) if species' traits could predict this response, and (3) the cross-regional consistency of trait-response relationships. Most beetle populations declined following any degree of forest conversion; these declines were strongest for Neotropical species. The relationship between traits and population trend was greatly influenced by local and biogeographic context. We discuss the ability of species' traits to explain population trends and suggest several ways to strengthen trait-response models.
Dung-inhabiting pest flies are one of the main problems associated with the accumulation of cattle dung. This work analyzes the diversity and dynamics of a coprophilous community from northern Buenos Aires, Argentina, in a search for potential biocontrol agents. Thirty-six dung pads of 3 age categories and 4 microhabitats were collected on each sampling date and examined for their arthropod fauna. Some of the species with undefined feeding behavior were subjected to feeding trials in the laboratory. We found 34 coprophagous species, 47 predators, and 13 parasitoids. The combination of the results of the feeding trials, co-occurrence and abundance data of the prey and predator populations, and direct field observations were used to put together a trophic web and hypothesis on the dynamics of the community. Dung scarabs cause significant reductions in immature dung fly survival by burying and desiccating large amounts of dung. The Philonthini (Coleoptera: Staphylinidae) are the most abundant and rich predator group, although they are slow to respond to variations in fly populations. However, predatory flies show the same abundance curves as their prey flies. Predatory beetles and flies, dung scarabs, and pupal parasitoids cause additive mortality to the fly population, whereas larval parasitoids cause some compensatory mortality. Four species of staphylinids, 1 predatory muscid, and a coprophagous scarab could have potential as biocontrol agents. The perspectives of success and convenience of a horn fly biocontrol scheme in southern South America are discussed.