Several fruit fly species of the genus Drosophila are common human commensals, yet their ecology in urban environments remains understudied. We launched a Citizen Science project all across Austria to sample Drosophila specimens in- and outdoors – particularly focusing on the capital city of Vienna and neighboring suburban areas, engaging 168 participants. From May to December 2024, 91 participants returned 278 traps, yielding 19,100 flies from 13 species. Notably, D. virilis and D. mercatorum were recorded in Austria for the first time, with D. mercatorum dominating in urban environments. By combining species abundance data with comprehensive climatic, demographic, economic and other earth observation data available for the sampled geographic region, we performed species distribution modeling, which revealed that D. melanogaster preferred semi-natural areas, while D. mercatorum was dominant in highly disturbed urban sites. Moreover, by investigating genome-wide data from more than 40 pooled D. melanogaster samples in the context of quantitative genomic data from hundreds of European Drosophila samples collected in rural areas, we find that urban flies from Vienna are closely related to fly populations collected in close-by regions, which indicates that their genetic composition is predominantly influenced by local populations. However, a few outlier samples show signals of migration from distant populations – most like as a result of human economic traffic. A final survey indicated strong participant engagement and increased interest in biodiversity. Our project demonstrates the power of Citizen Science in studying urban insect ecology while fostering public interest in science.

Urbanization alters animal habitats, creating selective pressures on wildlife and underscoring the growing relevance of cities for biodiversity conservation. This study investigates how urbanization affects the genetic structure and survival of Eurasian red squirrels (Sciurus vulgaris) across three contrasting habitats in Berlin, Germany: a woodland area, a walled urban cemetery, and a highly frequented urban park used for dog walking, recreational stays and public events such as festivals. Since 2021, red squirrels have been live-trapped biannually in spring and autumn across three study sites representing different levels of urbanization, resulting in a sample of over 140 marked individuals.We genotyped all individuals at 16 microsatellite loci and analysed genetic structure using Bayesian clustering with STRUCTURE. Additionally we calculated standard population genetic metrics to assess genetic diversity and differentiation among sites. Capture–recapture data were analysed using Cormack–Jolly–Seber models to estimate survival and detection probabilities in open populations. Our results reveal detectable genetic structuring between sites, potentially shaped by urban fragmentation.The woodland area and the cemetery show similar genetic structure while the urban park not. The urban park showed also a higher inbreeding rate than the other study sites. Survival varied with season, sex, and degree of urbanization, with lower survival for females in urban parksSurvival probabilities differed between males and females depending on site-specific urbanization levels. This study shows how urbanization shapes genetic structure and survival in red squirrels, offering insights into their persistence in cities and highlighting factors that support long-term population viability in urban environments.

Human-dominated ecosystems reshape wildlife communities, particularly predator-prey relationships. Humans often function as super-predators and suppress or extirpate conflict-prone carnivores. As such, the gray wolf (Canis lupus) is only recently returning to former ranges across Europe after centuries of absence, negotiating its place alongside other carnivores, wild prey, and a diverse patchwork of human disturbance. We investigated spatiotemporal habitat use and species interactions using a systematic camera-trapping survey in Poland’s Tuchola Forest – a landscape recolonized by wolves approximately a decade ago. Our models reveal distinct temporal patterns and scale-dependent associations, highlighting a tense push-and-pull dynamic in which wolves are drawn towards prey while avoiding human activity. Despite a legal hunting ban, wolves continue to exhibit fear of humans. They co-occur with mesopredators and show limited direct association. While much ecological research remains focused on protected or low-impact areas, our study offers insight into adaptive strategies and niche partitioning under layered pressures in a densely human-modified landscape.

Genetic diversity contributes to the capacity of populations to cope with environmental change, including those brought about by human impacts like urbanization and agriculture. Understanding the extent to which population genetic processes are associated with environmental factors across species is a powerful way to examine the processes maintaining patterns of biodiversity. The field of macrogenetics addresses these types of questions by synthesizing publicly available data to study population genetics at broad spatial and taxonomic scales.

This presentation showcases a macrogenetic analysis of Bombus. We compiled a dataset consisting of 4620 individuals across 243 populations and 14 Bombus species. The dataset is built using microsatellites, which are highly polymorphic and neutrally evolving, from population genetics studies. First, we estimated two measures of genetic diversity (allelic richness and gene diversity). We then used mixed effects linear regression models to test the effects of human-driven land use change, such as urbanization and agriculture, on the genetics of Bombus populations. In areas with a higher human footprint, some species, such as B. hypnorum and B. ruderatus tended to have lower levels of genetic diversity. On the contrary, other species such as B. occidentalis and B. terrestris had higher levels of genetic diversity in areas with a higher human footprint. This pattern may be influenced by their role as commercial pollinators in fields and greenhouses. Using such analyses can elucidate how land use changes impact populations and their genetic diversity, which can in turn be used to inform conservation efforts.

Heatwave are becoming more frequent and intense due to climate change, posing a significant threat to global biodiversity. While the decline of crucial pollinators like bumblebees is well-documented, the specific impact of heatwaves on their developmental stages remains largely unknown. We investigated the effects of varying heatwave lengths (3-7 days) and intensities (36-38°C) on Bombus terrestris pupae in vitro. Our findings reveal that pupal emergence can be drastically reduced, and wing deformities increased significantly. Our study highlights the profound consequences of heatwaves on bumblebee pupal development, with potential cascading effects on colony fitness, local populations, and ecosystem services.

Climate change disrupts vital ecological processes and biotic interactions. Recent increases in the frequency and severity of heatwaves prompt the evaluation of physiological processes that ensure the maintenance of key ecosystem services such as pollination. Experimental heatwaves are used to investigate how high temperatures affect the bumblebees’ ability to detect floral scents. Heatwaves induced strong reductions in antennal responses to floral scents, and these reductions were
generally stronger in workers than in males. There was no consistent pattern of recovery 24 h after heat events. The results suggest that the projected increased frequency and severity of heatwaves may compromise bumblebee-mediated pollination services by disrupting the chemical communication between plants and pollinators. The reduced chemosensitivity can decrease the bumblebees’ abilities to locate food sources and lead to declines in colonies and populations.