Dung Beetle Assemblages Attracted to Cow and Horse Dung: The Importance of Mouthpart Traits, Body Size, and Nesting Behavior in the Community Assembly Process.

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.

Effects of urbanization on taxonomic, functional and phylogenetic avian diversity in Europe.

Europe is an urbanized continent characterized by a long history of human-wildlife interactions. This study aimed to assess the effects of specific elements of urbanization and urban pollution on complementary avian diversity metrics, to provide new insights on the conservation of urban birds. Our study recorded 133 bird species at 1624 point counts uniformly distributed in seventeen different European cities. Our results thus covered a large spatial scale, confirming both effects of geographical and local attributes of the cities on avian diversity. However, we found contrasting effects for the different diversity components analyzed. Overall, taxonomic diversity (bird species richness), phylogenetic diversity and relatedness were significantly and negatively associated with latitude, while functional dispersion of communities showed no association whatsoever. At the local level (within the city), we found that urban greenery (grass, bush, and trees) is positively correlated with the number of breeding bird species, while the building cover showed a detrimental effect. Functional dispersion was the less affected diversity metric, while grass and trees and water (rivers or urban streams) positively affected the phylogenetic diversity of avian communities. Finally, the phylogenetic relatedness of species increased with all the main indicators of urbanization (building surface, floors, pedestrian's density and level of light pollution) and was only mitigated by the presence of bushes. We argue that maintaining adequate levels of avian diversity within the urban settlements can help to increase the potential resilience of urban ecosystems exposed to the stress provoked by rapid and continuous changes. We listed some characteristics of the cities providing positive and negative effects on each facet of urban avian diversity.

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.

Effects of grazing intensity and the use of veterinary medical products on dung beetle biodiversity in the sub-mountainous landscape of Central Italy.

Grazing extensification and intensification are among the main problems affecting European grasslands. We analyze the impact of grazing intensity (low and moderate) and the use of veterinary medical products (VMPs) on the dung beetle community in the province of Pesaro-Urbino (Italy). Grazing intensity is a key factor in explaining the diversity of dung beetles. In the case of the alpha diversity component, sites with a low level of grazing activity-related in a previous step to the subsequent abandonment of traditional farming-is characterized by a loss of species richness (q = 0) and a reduction in alpha diversity at the levels q = 1 and q = 2. In the case of beta diversity, sites with a different grazing intensity show remarkable differences in terms of the composition of their species assemblages. The use of VMPs is another important factor in explaining changes in dung beetle diversity. In sites with a traditional use of VMPs, a significant loss of species richness and biomass is observed, as is a notable effect on beta diversity. In addition, the absence of indicator species in sites with a historical use of VMPs corroborates the hypothesis that these substances have a ubiquitous effect on dung beetles. However, the interaction between grazing activity and VMPs when it comes to explaining changes in dung beetle diversity is less significant (or is not significant) than the main effects (each factor separately) for alpha diversity, biomass and species composition. This may be explained if we consider that both factors affect the various species differently. In other words, the reduction in dung availability affects several larger species more than it does very small species, although this does not imply that the former are more susceptible to injury caused by the ingestion of dung contaminated with VMPs. Finally, in order to prevent negative consequences for dung beetle diversity, we propose the maintenance of a moderate grazing intensity and the rational use of VMPs. It is our view that organic management can prevent excessive extensification while providing an economic stimulus to the sector. Simultaneously, it can also prevent the abuse of VMPs.