Nontoxic effects of thymol, carvacrol, cinnamaldehyde, and garlic oil on dung beetles: A potential alternative to ecotoxic anthelmintics.

The sustainability of the traditional extensive livestock sector will only be possible if healthy dung-decomposing insect communities are preserved. However, many current pharmaceutical anthelmintics are harmful to dung beetles, their presence can have a negative impact on biological systems. Phytochemical anthelmintics are an alternative to ecotoxic synthetic pharmaceutical anthelmintics, although ecotoxicological tests of their possible indirect effects on dung beetles are required to demonstrate their viability. In this study, the potential ecotoxicity of thymol, carvacrol, cinnamaldehyde and garlic oil (diallyl disulfide and diallyl trisulfide) were tested for the first time. Inhibition of antennal response was measured as a relevant parameter by obtaining relevant toxicity thresholds derived from concentration‒response curves, such as the IC50. All phytochemical compounds tested were demonstrated to be suitable alternative candidates to the highly ecotoxic compound ivermectin, considering their non-toxicity to nontarget organisms. Residues of the phytochemical antiparasitics found in cattle droppings were extremely low, even undetectable in the case of diallyl disulfide and diallyl trisulfide. Furthermore, our results showed that none of the phytochemical compounds have ecotoxic effects, even at extremely high concentrations, including those almost 1000 times higher than what is most likely to be found in dung susceptible to ingestion by dung beetles in the field. We can conclude that the four selected phytochemical compounds meet the requirements to be considered reliable alternatives to ecotoxic veterinary medicinal products, such as ivermectin.

Green synthesis, characterization, and biochemical impacts of new bioactive isoxazoline-sulfonamides as potential insecticidal agents against the Sphodroxia maroccana Ley.

BACKGROUND: Sphodroxia maroccana Ley is a pest of cork oak crops that damages the roots of seedlings and can severely impair cork oak regeneration. Since the banning of carbosulfan and chlorpyriphos, which were widely used against the larvae of Sphodroxia maroccana because of their harmful impact on the environment, until now there has been no pesticide against these pests. Therefore, it is particularly urgent to develop highly effective insecticidal molecules with novel scaffolds. Isoxazolines are a class of insecticides that act on γ-aminobutyric acid (GABA)-gated chloride channel allosteric modulators. In this work, a green synthesis of novel 3,5-disubstituted isoxazoline-sulfonamide derivatives was achieved in water via ultrasound-assisted four-component reactions, and their insecticidal activities against fourth-instar larvae of S. maroccana were evaluated. RESULTS: Most of the tested compounds showed insecticidal activity compared to fluralaner as positive control and commercially available insecticide. Especially, the isoxazoline-secondary sulfonamides containing halogens (Br and Cl) on the phenyl group attached to the isoxazoline, 6g (LC50 = 0.31 mg/mL), 6j (LC50 = 0.38 mg/mL), 6k (LC50 = 0.18 mg/mL), 6L (LC50 = 0.49 mg/mL), 6m (LC50 = 0.24 mg/mL), 6q (LC50 = 0.46 mg/mL), exhibited much higher larvicidal activity than fluralaner (LC50 = 0.99 mg/mL). CONCLUSION: Novel isoxazolines containing sulfonamide moieties were designed, synthesized and confirmed by two single-crystal structures of 4e and 6q. Their bioassay results showed significant larvicidal activity with significant morphological changes in vivo. These results will lay the foundation for the further discovery and development of isoxazoline-sulfonamide derivatives as novel crop protection larvicides of cork oak. © 2023 Society of Chemical Industry.

A trait-based framework for dung beetle functional ecology.

Traits are key for understanding the environmental responses and ecological roles of organisms. Trait approaches to functional ecology are well established for plants, whereas consistent frameworks for animal groups are less developed. Here we suggest a framework for the study of the functional ecology of animals from a trait-based response-effect approach, using dung beetles as model system. Dung beetles are a key group of decomposers that are important for many ecosystem processes. The lack of a trait-based framework tailored to this group has limited the use of traits in dung beetle functional ecology. We review which dung beetle traits respond to the environment and affect ecosystem processes, covering the wide range of spatial, temporal and biological scales at which they are involved. Dung beetles show trait-based responses to variation in temperature, water, soil properties, trophic resources, light, vegetation structure, competition, predation and parasitism. Dung beetles' influence on ecosystem processes includes trait-mediated effects on nutrient cycling, bioturbation, plant growth, seed dispersal, other dung-based organisms and parasite transmission, as well as some cases of pollination and predation. We identify 66 dung beetle traits that are either response or effect traits, or both, pertaining to six main categories: morphology, feeding, reproduction, physiology, activity and movement. Several traits pertain to more than one category, in particular dung relocation behaviour during nesting or feeding. We also identify 136 trait-response and 77 trait-effect relationships in dung beetles. No response to environmental stressors nor effect over ecological processes were related with traits of a single category. This highlights the interrelationship between the traits shaping body-plans, the multi-functionality of traits, and their role linking responses to the environment and effects on the ecosystem. Despite current developments in dung beetle functional ecology, many knowledge gaps remain, and there are biases towards certain traits, functions, taxonomic groups and regions. Our framework provides the foundations for the thorough development of trait-based dung beetle ecology. It also serves as an example framework for other taxa.

Biomagnification and body distribution of ivermectin in dung beetles.

A terrestrial test system to investigate the biomagnification potential and tissue-specific distribution of ivermectin, a widely used parasiticide, in the non-target dung beetle Thorectes lusitanicus (Jekel) was developed and validated. Biomagnification kinetics of ivermectin in T. lusitanicus was investigated by following uptake, elimination, and distribution of the compound in dung beetles feeding on contaminated faeces. Results showed that ivermectin was biomagnified in adults of T. lusitanicus when exposed to non-lethal doses via food uptake. Ivermectin was quickly transferred from the gut to the haemolymph, generating a biomagnification factor (BMFk) three times higher in the haemolymph than in the gut after an uptake period of 12 days. The fat body appeared to exert a major role on the biomagnification of ivermectin in the insect body, showing a BMFk 1.6 times higher than in the haemolymph. The results of this study highlight that the biomagnification of ivermectin should be investigated from a global dung-based food web perspective and that the use of these antiparasitic substances should be monitored and controlled on a precautionary basis. Thus, we suggest that an additional effort be made in the development of standardised regulatory recommendations to guide biomagnification studies in terrestrial organisms, but also that it is necessary to adapt existing methods to assess the effects of such veterinary medical products.

Author Correction: First assessment of the comparative toxicity of ivermectin and moxidectin in adult dung beetles: Sub-lethal symptoms and pre-lethal consequences.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Chemosystematics Using Cuticular Compounds: A Powerful Tool to Separate Species in Mediterranean Dung Beetles (Coleoptera: Geotrupidae).

The use of chemical characters to infer a phylogeny is known to be promising to ascertain phylogenetic relationships in controversial groups. Dung beetle classifications containing the Geotrupidae family, based on morphological characters and genes, are debated with respect to the subfamilies, such as the Bolboceratids. In our study, we used different approaches to generate and compare the Geotrupidae phylogenies based on genetics and chemotaxonomy. Cuticular compounds were analyzed for 12 species of Mediterranean dung beetles to build a chemical phylogeny. In addition, mitochondrial and nuclear marker concatenation have been used to elaborate the molecular phylogeny. Using the cuticular compound continuous data, our results showed that each species was associated with a specific chemical pattern and that all individuals belonging to the same species displayed a similar chemical blend. The most distant species was Bolbelasmus gallicus, with an evident distinction from the other species due to several compounds. The maximum parsimony tree showed that all genera belonging to a Geotrupidae subfamily were grouped in the same clade, with B. gallicus species isolated in another clade, similar to the chemotaxonomy grouping. A strong positive correlation between chemotaxonomy and genetic phylogeny has been demonstrated, underlying a genetic basis for cuticular hydrocarbon variations. Our results are congruent with previous studies using morphological or genetic data. Our results also showed that only 10 compounds can be used to distinguish at least six species of dung beetle and that chemotaxonomy could become a useful and affordable tool to determine phylogenetic relationships in insects.

First assessment of the comparative toxicity of ivermectin and moxidectin in adult dung beetles: Sub-lethal symptoms and pre-lethal consequences.

Among macrocyclic lactones (ML), ivermectin (IVM) and moxidectin (MOX) potentially affect all Ecdysozoan species, with dung beetles being particularly sensitive. The comparative effects of IVM and MOX on adult dung beetles were assessed for the first time to determine both the physiological sub-lethal symptoms and pre-lethal consequences. Inhibition of antennal response and ataxia were tested as two intuitive and ecologically relevant parameters by obtaining the lowest observed effect concentration (LOEC) values and interpolating other relevant toxicity thresholds derived from concentration-response curves (IC50, as the concentration of each ML where the antennal response is inhibited by half; and pLC50, as the quantity of ingested ML where partial paralysis was observed by half of treated individuals) from concentration-response curves. Both sub-lethal and pre-lethal symptoms obtained in this study coincided in that IVM was six times more toxic than MOX for adult dung beetles. Values of LOEC, IC50 and pLC50 obtained for IVM and MOX evaluated in an environmental context indicate that MOX, despite needing more time for tis elimination in the faeces, would be twice as harmful to dung beetles as IVM. This approach will be valuable to clarify the real impact of MLs on dung beetle health and to avoid the subsequent environmental consequences.

Ivermectin residues disrupt dung beetle diversity, soil properties and ecosystem functioning: An interdisciplinary field study.

Ivermectin is the most common endectocide used to control parasites affecting livestock. Short-term physiological and behavioural effects of ivermectin on dung beetles may have long-term consequences for beetle populations and ecosystem functioning. Long-term effects of the use of ivermectin can be estimated by comparing dung assemblages and ecosystem functions in areas with conventional ivermectin-treated livestock and environmentally similar areas in which livestock are not treated with veterinary medical products (organic farming). In this study, we investigated both short-term and long-term effects of the administration of ivermectin on the characteristics of dung beetle assemblages and the services they provided in a protected area (Doñana National Park, SW Spain). We examined short-term dung colonization, dwelling, relocation, and disaggregation rates and the associations between these processes and the key assemblage parameters of species richness, abundance, biomass and functional diversity. Furthermore, we analysed changes in soil physical-chemical properties and processes. Short-term differences were observed in the total amount of dung relocated by dung beetles at different colonization vs. emigration stages, suggesting that dung beetles in this area were affected by the recent treatments of livestock with ivermectin. Moreover, short-term effects could also be responsible for the significant differences in dung spreading rates between sites. Conventional use of ivermectin disrupted ecosystem functioning by affecting species richness, abundance and biomass. The decrease in diversity parameters was related to a reduction in the functional efficiency, which resulted in the long-term accumulation of dung on the ground and considerable changes in soil functionality.

How Guilds Build Success; Aspects of Temporal Resource Partitioning in a Warm, Temperate Climate Assemblage of Dung Beetles (Coleoptera: Scarabaeidae).

Succession in local dung beetle assemblages influences their delivery of ecological functions in natural and modified environments globally. Short-term changes in dung beetle (Coleoptera: Scarabaeidae) species richness, abundance, and biomass were investigated in standardized dung pads in northern, coastal Turkey. For mean tunneling guild abundance, dung deposition time, dung exposure period, and their interaction were significant, and for mean dung dwelling guild abundance, dung exposure period was significant, as was the interaction with dung deposition time, which collectively evidenced temporal resource partitioning, based principally on differences in diel activity. Succession was highly compressed, with maximum abundance at 12 h and maximum species richness at 24 h. A large ball roller and small- to medium-sized tunnelers dominated different periods in the first 24 h but were superseded by dwellers. Regression analysis demonstrated a significant, positive relationship between species richness and the evenness of abundance for both dung deposition times. Correlation analysis generally showed strong, positive correlations between tunneling species, low correlations between tunneling and dwelling species, and low correlations between dwelling species. Niche partitioning based on size difference appears to have acted on the environmental filtering of tunneling species along the temporal gradient of declining moisture, thereby limiting the number of abundant, concurrent species. The aggregation of tunneling species provided opportunities for the less competitive dwelling species to occupy less densely populated zones termed probability refuges. The network of strong, positive habitat' correlations between tunneling species may indicate that their collective functionality is vulnerable to loss of efficiency if species are lost.

Temporal Resource Partitioning and Interspecific Correlations in a Warm, Temperate Climate Assemblage of Dung Beetles (Coleoptera: Scarabaeidae).

Guilds of dung dwelling and tunneling dung beetles coexist in local assemblages in warm temperate regions, despite the tendency of dwellers to be inferior competitors. A field experiment on the Black Sea coast of Turkey examined the role of temporal resource partitioning in their coexistence. Standardized dung pads deposited at 4 h intervals through a 24 h period in summer were collected 12, 24, or 48 h later. Adults from 10 tunneling and seven dung dwelling species were collected. The tunnelers contributed a high proportion of both total abundance and biomass. There was a significant effect of dung deposition time and exposure period on mean tunneler abundance. Mean tunneler abundance was nearly seven times higher in dung deposited at 06:00 than at 18:00. The dwellers reduced the potential for competitive interactions with tunnelers by relatively uniform dispersal across the six dung deposition times. The distinctly different dung use patterns by dwellers and tunnelers demonstrated temporal resource partitioning. Interspecific correlation coefficients were also determined because interspecific relationships are at the core of resource partitioning. Total tunneler and dweller abundances were not correlated. Overall, there were strong positive correlations between tunneling species and low correlations between tunneling and dwelling species, and between dwelling species. The five most abundant tunnelers, from two tribes and three genera, were strongly positively correlated. There were substantial size differences among the four most abundant tunnelers that probably facilitate their coexistence.

Ivermectin alters reproductive success, body condition and sexual trait expression in dung beetles.

Ivermectin is a very common parasiticide used in livestock. It is excreted in the dung and has negative effects on survival and reproduction of dung-degrading organisms, including dung beetles. Here we exposed the dung beetle Euoniticellus intermedius to different concentrations of ivermectin in the food and evaluated reproductive success and the expression of traits associated with survival and reproduction under laboratory conditions. It is the first time the effects of ivermectin were evaluated on offspring physiological condition and the expression of a secondary sexual trait. We also registered the number of emerged beetles, sex ratio and body size of emerged adult beetles. Besides reducing the number of emerged beetles and body size, as found in the same and other insects, ivermectin at high doses reduced muscle mass while at intermediate doses it increased lipid mass. Ivermectin changed offspring sex ratio and at high doses increased the size of male horn, which is an important trait defining the male mating success. Our results highlight the importance of regulating parasiticide usage in livestock in order to maintain ecosystem services provided by dung beetles and confirm that contaminants impose new environmental conditions that not only impact on wild animal survival, but also on evolutionary processes such as sexual selection.

Effects of an herbicide on physiology, morphology, and fitness of the dung beetle Euoniticellus intermedius (Coleoptera: Scarabaeidae).

Some agrochemical compounds threaten nontarget organisms and their functions in the ecosystem. The authors experimentally evaluated the effects of one of the most common herbicide mixtures used worldwide, containing 2,4-dichlorophenoxyacetic acid and picloram, on dung beetles, which play fundamental roles in the function of natural and managed ecosystems. The present study employed techniques of physiology and geometric morphometrics, besides including fitness measurements, to assess the effects of the herbicide in the introduced beetle Euoniticellus intermedius. Because herbicide components promote oxidative stress and affect survival in certain insects, the authors predicted negative effects on the beetles. Unexpectedly, no effect of herbicide concentration was found on clutch size, sex ratio, and fluctuating asymmetry, and it even increased physiological condition and body size in exposed beetles. Because the studied species presents 2 male morphs, the authors, for the first time, evaluated the effect of a pollutant on the ratio of these morphs. Contrary to the prediction, the herbicide mixture increased the proportion of major males. Thus, the herbicide does not threaten populations of the studied beetles. The present study discusses how both negative and positive effects of pollutants on wild animals modify natural and sexual selection processes occurring in nature, which ultimately impact population dynamics. The authors recommend the use of physiological and geometric morphometrics techniques to assess the impact of pollutants on nontarget animals. Environ Toxicol Chem 2017;36:96-102. © 2016 SETAC.

Analysis and dissipation of the antiparasitic agent ivermectin in cattle dung under different field conditions.

Cattle treated with the veterinary parasiticide ivermectin fecally excrete residues. The authors report the exposition and dissipation characteristics of these residues in dung of ivermectin-treated cattle and in soil beneath this dung on pastures in Canada, France, Switzerland, and The Netherlands. Residues were quantified for dung collected from cattle after 3 d, 7 d, 14 d, and 28 d posttreatment and subsequently exposed in the field for up to 13 mo. The authors optimized a high-performance liquid chromatography-fluorescence detection method to detect ivermectin residues in dung and soil matrices. They showed that a solid phase extraction and purification step generally can be eliminated to reduce the time and cost of these analyses. They also found that the addition of water to relatively dry samples improves the extraction efficiency of residues. They then analyzed the field samples to document differences in ivermectin dissipation in cattle dung among sites, with 50% dissipation times of up to 32 d and 90% dissipation times >396 d. They further showed that the dissipation characteristics of residues are comparable between dung of ivermectin-treated cattle and dung to which ivermectin has been added directly. Lastly, they report the first use of a desorption electrospray ionization-high-resolution-mass spectrometric method to detect residues of metabolites in a dung matrix. Environ Toxicol Chem 2016;35:1924-1933. © 2016 SETAC.

Nontarget effects of ivermectin residues on earthworms and springtails dwelling beneath dung of treated cattle in four countries.

The authorization of veterinary medicinal products requires that they be assessed for nontarget effects in the environment. Numerous field studies have assessed these effects on dung organisms. However, few studies have examined effects on soil-dwelling organisms, which might be exposed to veterinary medicinal product residues released during dung degradation. The authors compared the abundance of earthworms and springtails in soil beneath dung from untreated cattle and from cattle treated 0 d, 3 d, 7 d, 14 d, and 28 d previously with ivermectin. Study sites were located in different ecoregions in Switzerland (Continental), The Netherlands (Atlantic), France (Mediterranean), and Canada (Northern Mixed Grassland). Samples were collected using standard methods from 1 mo to 12 mo after pat deposition. Ivermectin concentrations in soil beneath dung pats ranged from 0.02 mg/kg dry weight (3 mo) to typically <0.006 mg/kg dry weight (5-7 mo). Earthworms were abundant and species-rich at the Swiss and Dutch sites, less common with fewer species at the French site, and essentially absent at the Canadian site. Diverse but highly variable communities of springtails were present at all sites. Overall, results showed little effect of residues on either earthworms or springtails. The authors recommend that inclusion of soil organisms in field studies to assess the nontarget effects of veterinary medicinal products be required only if earthworms or springtails exhibit sensitivity to the product in laboratory tests. Environ Toxicol Chem 2016;35:1959-1969. © 2015 SETAC.

A four-country ring test of nontarget effects of ivermectin residues on the function of coprophilous communities of arthropods in breaking down livestock dung.

By degrading the dung of livestock that graze on pastures, coprophilous arthropods accelerate the cycling of nutrients to maintain pasture quality. Many veterinary medicinal products, such as ivermectin, are excreted unchanged in the dung of treated livestock. These residues can be insecticidal and may reduce the function (i.e., dung-degradation) of the coprophilous community. In the present study, we used a standard method to monitor the degradation of dung from cattle treated with ivermectin. The present study was performed during a 1-yr period on pastures in Canada, France, The Netherlands, and Switzerland. Large effects of residue were detected on the coprophilous community, but degradation of dung was not significantly hampered. The results emphasize that failure to detect an effect of veterinary medicinal product residues on dung-degradation does not mean that the residues do not affect the coprophilous community. Rather, insect activity is only one of many factors that affect degradation, and these other factors may mask the nontarget effect of residues. Environ Toxicol Chem 2016;35:1953-1958. © 2015 SETAC.

Validation of a standard field test method in four countries to assess the toxicity of residues in dung of cattle treated with veterinary medical products.

Registration of veterinary medical products includes the provision that field tests may be required to assess potential nontarget effects associated with the excretion of product residues in dung of treated livestock (phase II, tier B testing). However, regulatory agencies provide no guidance on the format of these tests. In the present study, the authors report on the development of a standardized field test method designed to serve as a tier B test. Dung was collected from cattle before and up to 2 mo after treatment with a topical application of a test compound (ivermectin). Pats formed of dung from the different treatments were placed concurrently in the field to be colonized by insects. The abundance, richness, and diversity of insects developing from egg to adult in these pats were compared across treatments using analysis of variance tests. Regression analyses were used to regress abundance, richness, and diversity against residue concentrations in each treatment. Results of the regression were used to estimate mean lethal concentration (LC50) values. The robustness of the method and the repeatability of its findings were assessed concurrently in 4 countries (Canada, France, Switzerland, and The Netherlands) in climatically diverse ecoregions. Results were generally consistent across countries, and support the method's formal adoption by the European Union to assess the effects of veterinary medical product residues on the composition and diversity of insects in dung of treated livestock. Environ Toxicol Chem 2016;35:1934-1946. © 2015 Crown in the right of Canada. Published by Wiley Periodicals Inc., on behalf of SETAC.

Low doses of ivermectin cause sensory and locomotor disorders in dung beetles.

Ivermectin is a veterinary pharmaceutical generally used to control the ecto- and endoparasites of livestock, but its use has resulted in adverse effects on coprophilous insects, causing population decline and biodiversity loss. There is currently no information regarding the direct effects of ivermectin on dung beetle physiology and behaviour. Here, based on electroantennography and spontaneous muscle force tests, we show sub-lethal disorders caused by ivermectin in sensory and locomotor systems of Scarabaeus cicatricosus, a key dung beetle species in Mediterranean ecosystems. Our findings show that ivermectin decreases the olfactory and locomotor capacity of dung beetles, preventing them from performing basic biological activities. These effects are observed at concentrations lower than those usually measured in the dung of treated livestock. Taking into account that ivermectin acts on both glutamate-gated and GABA-gated chloride ion channels of nerve and muscle cells, we predict that ivermectin's effects at the physiological level could influence many members of the dung pat community. The results indicate that the decline of dung beetle populations could be related to the harmful effects of chemical contamination in the dung.

A review on the toxicity and non-target effects of macrocyclic lactones in terrestrial and aquatic environments.

The avermectins, milbemycins and spinosyns are collectively referred to as macrocyclic lactones (MLs) which comprise several classes of chemicals derived from cultures of soil micro-organisms. These compounds are extensively and increasingly used in veterinary medicine and agriculture. Due to their potential effects on non-target organisms, large amounts of information on their impact in the environment has been compiled in recent years, mainly caused by legal requirements related to their marketing authorization or registration. The main objective of this paper is to critically review the present knowledge about the acute and chronic ecotoxicological effects of MLs on organisms, mainly invertebrates, in the terrestrial and aquatic environment. Detailed information is presented on the mode-of-action as well as the ecotoxicity of the most important compounds representing the three groups of MLs. This information, based on more than 360 references, is mainly provided in nine tables, presenting the effects of abamectin, ivermectin, eprinomectin, doramectin, emamectin, moxidectin, and spinosad on individual species of terrestrial and aquatic invertebrates as well as plants and algae. Since dung dwelling organisms are particularly important non-targets, as they are exposed via dung from treated animals over their whole life-cycle, the information on the effects of MLs on dung communities is compiled in an additional table. The results of this review clearly demonstrate that regarding environmental impacts many macrocyclic lactones are substances of high concern particularly with larval instars of invertebrates. Recent studies have also shown that susceptibility varies with life cycle stage and impacts can be mitigated by using MLs when these stages are not present. However information on the environmental impact of the MLs is scattered across a wide range of specialised scientific journals with research focusing mainly on ivermectin and to a lesser extent on abamectin doramectin and moxidectin. By comparison, information on compounds such as eprinomectin, emamectin and selamectin is still relatively scarce.

How to test nontarget effects of veterinary pharmaceutical residues in livestock dung in the field.

To register veterinary medicinal products (VMPs) as parasiticides on pastured animals, legislation in the European Union requires an environmental risk assessment to test the potential nontarget effects of fecal residues on dung-dwelling organisms. Products with adverse effects in single-species laboratory tests require further, higher-tier testing to assess the extent of these effects on entire communities of dung-dwelling organisms under more realistic field or semifield conditions. Currently, there are no documents specifically written to assist researchers in conducting higher-tier tests or to assist regulators in interpreting the results of such tests in an appropriate context. Here we provide such a document, written by members of the SETAC Advisory Group DOTTS (Dung Organism Toxicity Testing Standardization) with research experience on dung fauna in central and southern Europe, Canada, Australia, and South Africa. This document briefly reviews the organisms that make up the dung community and their role in dung degradation, identifies key considerations in the design and interpretation of experimental studies, and makes recommendations on how to proceed.

Innate olfactory preferences in dung beetles.

The effects of insect larval diet on adult olfactory responses to host-plant or food volatiles are still debated. The induction of adult host preferences has been studied in insects with diverse ecologies, including parasitoids, flower-visitors and phytophagous species. We investigated this question for the first time in a coprophagous insect species. Larvae of the French scarab dung beetle Agrilinus constans were reared on four different artificial substrates containing dung from cattle, horse, sheep or wild boar, and responses of imagos to dung volatiles were then behaviourally tested in an olfactometer. We also reported the first analysis of the composition of different mammal dung volatiles. We showed that adult beetles were more attracted to cattle and sheep dung odours, and that larval feeding experience had no effect on the adult olfactory responses to dung volatiles. A second experiment showed that the presence of other insects inside the dung resource affects the process of dung selection by adults. We identified 64 chemical compounds from dung emissions, and showed that dung volatiles clearly differed among different mammal species, allowing olfactory discrimination by dung beetles. Our results suggest that resource selection in coprophagous insects may be based on innate olfactory preferences. Further experiments should examine whether Agrilinus adults can learn new dung odours, and whether larval diet may influence the behaviour of adults in other coprophagous species.