1. The degradation and replacement of natural ecosystems affect species abundance, diversity and interspecific interaction through the modification of resource availability and environmental conditions. Land uses preserving the forest canopy show higher species richness and similarity to the native forest.2. In this study, we explored changes in the trophic niche overlap of dung beetles between the native forest and different land uses in the semideciduous Atlantic forest, under the hypothesis that trophic niche overlap increases with species richness.3. We sampled dung beetles in protected native forests and four land uses (pine plantations, agroforestry parklands, silvo-pastoral systems and open pastures), using seven potential food sources (monkey, feline, tapir and deer dung, decomposing fruit, decomposing fungi and carrion). The species richness of each habitat, the trophic niche overlap and the relation between both measures were analysed. Also, we explored species trophic preferences in each habitat to explain and discuss the results obtained in trophic niche overlap measures.4. As expected, our results showed a positive relation between species richness and trophic niche overlap. Moreover, the addition of different resources in open habitats did not increase species richness, suggesting that resource availability may not be the main mechanism explaining the empoverished dung beetle community observed in open habitats. Other mechanisms, such as physiological restrictions, may play a role in limiting the use of these habitats. Studies on the mechanisms leading to the patterns of species abundance and diversity observed in land uses are necessary to propose management recommendations that increase the sustainability of open habitats.

de efecto del disturbio antrópico sobre la diversidad funcional, funciones ecosistémicas, servicios ecosistémicos y riqueza de especies. Las flechas continuas representan efectos directos y las flechas punteadas efectos indirectos. La línea punteada en verde representa el efecto indirecto del disturbio sobre los servicios ecosistémicos a

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in terrestrial ecosystems, insects face a wide range of temperatures among habitats and time; consequently, the thermal niche is one of the main determinants of habitat selection and temporal patterns of activity. the replacement of native forests changes micro-climatic conditions and reduces the diversity of dung beetles; however, the physiological mechanisms behind these changes are not clear. We explore the role of the thermal niche in dung beetles to explain the ability of native species to exploit human-created habitats. Using infrared thermography, we measured variables associated with the thermal niche in 17 native species and used linear mixed-effects model and ANOVAs to compare disturbed habitats and the native forest. endothermy and body mass explained the ability of dung beetles to exploit human-created open habitats. Small and diurnal species with very low endothermy were able to exploit deforested open habitats; evening/nocturnal/crepuscular species showed similar body mass and high endothermy in all habitats. Regarding thermoregulation mechanisms, none of the species (except one) showed defined or efficient mechanisms of physiological thermoregulation. in view of the accelerated process of forest replacement and climate change, a more profound understanding of the physiological requirements of species is essential to predict and mitigate future extinctions. At local scales, anthropogenic habitat disturbance usually modifies microclimatic conditions (e.g. forest canopy loss), resulting in novel thermal challenges for organisms (e.g. open habitats) 1,2. In tropical and subtropical forests, recent studies have shown a marked reduction in the abundance and taxonomic and functional diversity of dung beetles in land uses with complete loss of canopy cover, such as pastures devoted to cattle raising 2-4. In contrast, land uses preserving canopy cover (such as tree plantations and silvopastoral systems) can partially preserve the structure of the dung beetle assemblages of the native forest 2,5-7. Differences in dung beetle diversity among land uses differing in canopy cover have been associated mainly with a marked increase in ground level temperature 2,8-10 and with the low tolerance of forest dung beetles to high temperatures (typical of open habitats during the day) 3,11-13. Although previous studies have suggested that the physiological intolerance of forest dung beetles to high temperatures is a potential constraint to exploit disturbed habitats 2,3,14 , this hypothesis has never been tested. This knowledge gap on dung beetle thermal biology led us to ask the following question: can the thermal niche of dung beetles explain the occupation of disturbed habitats, and taxonomic and functional changes reported in previous studies? We tested this central question in the southern Atlantic forest of South America, one of the most diverse and threatened ecosystems worldwide 15-17. The physiological responses of insects, especially those associated with temperature (endothermy, thermoregulation, thermal tolera...

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Trophic ecology of dung beetles has been widely studied because of the important ecological role of these taxa. However, previous studies have focused on a limited number of potential food items (mainly vertebrate dung and carrion) and have used only one approach (either field or laboratory). Moreover, recent studies showed high abundance of dung beetles in defaunated areas with a low abundance of these resources. In this study, we combined a field and laboratory approach to explore dung beetle trophic attraction to different potential native resources in the Atlantic forest; and we evaluated whether results can explain the high abundance of dung beetles in defaunated areas. Through laboratory olfactometry experiments, we first exposed individuals to vertebrate carrion, omnivorous dung, and decomposing fungi. Then, we exposed species that exhibited a preference for dung to monkey, tapir, and feline dung; and those that preferred carrion and decomposing fungi to chicken, cow meat, and arthropod carcasses. We compared trophic attractions in the field and laboratory conditions with generalised additive models. We found that coprophagous species preferred monkey dung, and all necrophagous and sapro‐necrophagous species preferred arthropod carcasses. These results suggest that the importance of arthropods carcasses as an important resource for dung beetles has been largely underestimated. The results of this study might provide an explanation for the high abundance of necrophagous and sapro‐necrophagous dung beetles in defaunated areas. In addition, the use of omnivorous dung and arthropod carcasses could be an effective sampling method for dung beetle assemblages.

Dung beetles use excrement for feeding and reproductive purposes. Although they use a range of dung types, there have been several reports of dung beetles showing a preference for certain feces. However, exactly what determines dung preference in dung beetles remains controversial. In the present study, we investigated differences in dung beetle communities attracted to horse or cow dung from a functional diversity standpoint. Specifically, by examining 18 functional traits, we sought to understand if the dung beetle assembly process is mediated by particular traits in different dung types. Species specific dung preferences were recorded for eight species, two of which prefer horse dung and six of which prefer cow dung. Significant differences were found between the functional traits of the mouthparts of the dung beetles attracted to horse dung and those that were attracted to cow dung. Specifically, zygum development and the percentage of the molar area and the conjunctive area differed between horse and cow dung colonizing beetles. We propose that the quantitative differences in the mouthpart traits of the species attracted to horse and cow dung respectively could be related to the differential capacity of the beetles to filtrate and concentrate small particles from the dung. Hence, the dung preference of dung beetles could be related to their ability to exploit a specific dung type, which varies according to their mouthpart traits. Moreover, we found that larger and nester beetles preferred cow dung, whereas smaller and non-nester beetles preferred horse dung. This finding could be related to the tradeoff between fitness and parental investments, and to the suitability of the trophic resource according to the season and species phenology.

Functional diversity has been defined as the value, range, distribution, and relative abundance of the functional traits of individuals that belong to an ecosystem. Thus, the functional response of organisms to environmental disturbances depends largely on their functional traits. Here, we evaluated dung beetle functional diversity associated to the Atlantic Forest replacement using a matrix with 25 functional traits (10 morphological, four ethological, and 11 physiological). We compared functional diversity among native and disturbed habitats with a multi and single trait approach. Contrary to previous studies, habitats with higher disturbance (open pasture) exhibited higher functional diversity compared to native forests, which could be explained by the incorporation of physiological response traits. Species of open disturbed habitats showed extreme values of such traits, explaining the observed pattern. The inclusion of several traits that represent both species ecology and morphology, and their physiology, generates different results to those observed in previous functional studies. This highlights the importance of including a large variety of functional traits in future functional diversity studies. We propose that functional traits must (1) be carefully chosen according to their biological and functional basis; (2) represent species ecology and physiology; and (3) include both effect and response traits. In addition, we consider it is extremely relevant to include a multi and single trait approach in functional diversity studies. A combination of all these considerations will provide a more realistic and complete overview of functional diversity patterns and the potential consequences of human disturbance on ecosystem functioning.