Dung beetles as direct and indirect providers of ecosystem services

Dung beetles (Coleoptera: Scarabaeoidea) are key ecosystem engineers due to their dung-feeding and nesting activities, which drive dung removal, soil mixing, nutrient cycling, plant growth, pest control, and seed dispersal. Recently, they have also emerged as model systems for studying invertebrate behaviour and host–microbe interactions. Research across multiple species has examined individual temperament, behavioural syndromes, gut microbiota composition, and effects on soil biogeochemistry. Although personality studies have long focused on vertebrates, increasing evidence indicates that invertebrates, including dung beetles, display consistent behavioural differences attributable to temperament. In the subsocial Copris umbilicatus, moderate to high repeatability was found for locomotor activity, thanatosis, and distress-call emission. Activity and thanatosis duration were negatively correlated: bolder individuals were more active and recovered faster, whereas fearful ones remained immobile longer. These traits were independent of sex and body size, and PCA confirmed inter-individual variability. Similar patterns occurred in Geotrupes mutator, a hornless, non-subsocial species, where activity and thanatosis were again highly repeatable and negatively correlated, supporting the generality of temperament across dung beetles. Among acoustic traits, only frequency showed repeatability, likely reflecting sex-based morphological differences in the stridulatory apparatus. Thus, locomotor and thanatosis behaviours reliably indicate temperament, while acoustic traits may require subtler interpretation. Dung beetles also harbour diverse gut microorganisms that influence host physiology and ecosystem processes. In alpine Trypocopris pyrenaeus, analyses revealed a small core microbiota and numerous individual-specific taxa, with distinct community structures between prokaryotes and fungi. Greater prokaryotic diversity correlated with higher functional potential, linking microbiota composition to both host health and ecological function. Comparative studies on three Onthophagus species showed that prokaryotic communities were primarily shaped by host identity, whereas fungal assemblages varied with dung type, reflecting transient environmental exposure. Despite taxonomic differences, functional redundancy was evident, underscoring the need to integrate taxonomic and functional data when interpreting microbial diversity. Externally, dung beetles modify soil microenvironments through burrowing and dung burial. Planar optode imaging in Onthophagus nuchicornis revealed microscale oxygen and pH heterogeneity generated over 96 hours. Buried dung balls developed anoxic zones lasting >45 hours and localized pH increases, fostering coexisting aerobic and anaerobic processes such as nitrification and denitrification. These conditions enhance microbial habitat diversity and nutrient turnover. Even under waterlogged conditions, beetle activity—tracked via fluorescent nanoparticles—persisted, confirming continued dung displacement. Quantitative measurements of soil mixing and dung removal demonstrated tangible ecosystem services including improved porosity and organic matter redistribution. Overall, this research highlights the complex ecological roles of dung beetles. Consistent behavioural syndromes in both subsocial and non-subsocial species underscore the relevance of temperament in invertebrate ecology. Their diverse and functionally redundant microbiota reveal intricate host–microbe associations, while their soil-modifying behaviour illustrates their capacity for fine-scale ecological engineering. Future integrative studies combining behavioural, microbial, and soil biogeochemical data will be key to fully elucidating the ecological significance of dung beetles and the role of individual variation within populations