Michelina Pusceddu

The yellow-legged hornet, Vespa velutina var. nigrithorax, is an invasive generalist predator that preys heavily on honeybees and other pollinators. Native to eastern China, northern Vietnam, and foothills of the Himalaya, it has invaded and now inhabits most of South Korea and western Europe. Here we summarize discoveries of V. velutina documented for the first time during 2025 in New Zealand (the first confirmed records from the southern hemisphere), Algeria (the first records from Africa), Northern Ireland, Denmark, and several European islands (Sardinia, the Azores, and the Isles of Scilly). We also review recent changes in the distribution of V. velutina elsewhere in Europe and North America. These range expansions highlight the high reproductive rate of the species; the extensive dispersal of young queens, both naturally and via shipments of goods by sea and over land; the ability to establish new populations despite low genetic variability; and the potential of V. velutina to harm pollinators and pollination systems.

The introduction, establishment, and spread of invasive alien species (IAS) pose a major threat to global biodiversity. Human activities, environmental and climate change, and intensification of international trade and transport networks have accelerated biological invasions, which show no signs of saturation (Seebens 2017; Seebens 2018). Sardinia is a key biodiversity hotspot in the central Mediterranean, characterized by high levels of endemism and ecological heterogeneity, which increase ecosystem vulnerability to biological invasions (Fois et al. 2020;Bazzato et al. 2021). Its strategic location and intense traffic further enhance the risk of IAS introduction and establishment. In this context, cross-border cooperation is essential for prevention, early detection, and management. Within this framework, the INTERREG Italy–France Maritime Project ALIEM Vigil - Measures for Limiting, Managing, and Monitoring the Introduction of Invasive Alien Species in Mediterranean Transport Zones promotes coordinated actions across Mediterranean transport zones. Project activities included mapping and characterization of entry points; capitalization of methodologies developed in previous ALIEM projects; expansion of surveillance and early warning systems; stakeholder training and awareness; and testing of innovative control and eradication strategies. This contribution presents the main outcomes achieved by the Sardinian research unit. Key outcomes comprise modelling the potential distribution of Vespa crabro in Sardinia under current and future climate scenarios (Bazzato et al. 2025), and the development of a global dataset of Stator limbatus occurrence records (Cocco et al. 2022), integrated with ecological and biogeographic information on host plants. Furthermore, the surveillance network enabled the prompt detection and elimination of the first Vespa velutina nest in Sardinia. No new introductions of alien xylophagous pests were detected at monitored entry points, and Cydalima perspectalis was recorded at very low population densities in the only Italian natural population of Buxus balearica , with minimal associated damage. These results are shared with project partners across the cooperation area and highlight the importance of cross-border collaboration to improve integrated approaches for IAS management, building on the legacy of previous ALIEM initiatives.

The Mediterranean basin is a global biodiversity hotspot where intense maritime traffic, tourism and commercial exchanges concentrate through seaports, airports and logistics platforms that act as preferential entry pathways for invasive alien species (IAS). Building on the achievements of the Interreg Italy-France Maritime projects ALIEM (2017-2020) and ALIEM APOSTROPHE (2020-2023), the ALIEM VIGIL project (2024-2027, 36 months) strengthens the coordinated prevention, early detection and management of both terrestrial and marine IAS across the French-Italian transboundary cooperation area (Corsica, Sardinia, Liguria, Tuscany and Provence-Alpes-Côte d'Azur). ALIEM VIGIL is structured around three complementary components. Work package 1 consolidates a cross-border surveillance network by upgrading the ALIEM NETWORK 3.0 collaborative platform, its mobile application and the GAIA mapping database, and by extending the characterisation and risk assessment of transit entry points. Work package 2 delivers joint training and awareness actions targeting port and airport authorities, transport operators, site managers and the general public, with harmonised pedagogical tools and a joint cross-border training pilot. Work package 3 designs and field-tests innovative protocols for the control and neutralisation of priority IAS, structured around an Identification–Development–Neutralisation (I-D-N) operational approach and consolidated into a single Transboundary Control Protocol. Led by the Corsica Environment Agency (OEC), the consortium gathers eight partners from France and Italy combining regional environmental authorities, universities, a national botanical conservatory and a natural history museum. Key deliverables include a shared platform, a Transboundary Management Plan, local management plans, harmonised identification and intervention protocols, and a transferable I-D-N approach. Through this integrative, networked and action-oriented approach, ALIEM VIGIL contributes directly to the EU Biodiversity Strategy for 2030, the EU IAS Regulation 1143/2014, the Kunming-Montreal Global Biodiversity Framework (Target 6) and the 2015 transboundary cooperation agreement for the study and management of invasive species in the Mediterranean.

Whether climate change will facilitate or constrain invasive alien species (IAS) remains a central unresolved question in invasion science, particularly in Mediterranean biodiversity hotspots where warming and aridification may alter invasion trajectories in non-linear ways. Robust local-scale forecasts are often limited by coarse environmental data, heterogeneous sampling effort, and spatial autocorrelation, reducing their reliability for management applications. Here, we developed a high-resolution climatic suitability forecasting framework for the alien European hornet Vespa crabro in Sardinia (Italy) (Pusceddu et al. 2019; Pusceddu et al. 2022), a Mediterranean island where the species was introduced in 2010 and currently shows a limited but expanding distribution in the northern sector. We integrated 303 spatially filtered and validated citizen-science occurrences, 40-m island-specific bioclimatic predictors, kernel density-based bias surfaces for pseudo-absence selection, spatial block cross-validation, and three tuned machine-learning algorithms (Artificial Neural Network (ANN), Gradient Boosting Machine (GBM), Random Forest (RF)) replicated across pseudo-absence sets and spatial folds (150 individual models) (Phillips et al. 2009; Barbet‐Massin et al. 2012; Hijmans 2012; Roberts et al. 2017; Valavi et al. 2019). Individual models were filtered using performance thresholds (Receiver Operating Characteristics (ROC) and its Area Under the Curve (AUC), AUC ≥ 0.7; True Skill Statistic, TSS ≥ 0.4), then weighted by validation performance and averaged into an ensemble forecasting model to project current and future suitability under SSP2-4.5 and SSP5-8.5 scenarios for 2040 and 2060. The obtained ensemble model was evaluated using the above-mentioned evaluation metrics and plotting the ROC curve. The final ensemble achieved high predictive performance (ROC = 0.95 ± 0.02; TSS = 0.78 ± 0.06), with Annual Mean Temperature and Precipitation of the Driest Month accounting for 61% of model contribution. Current projections identified extensive climatically suitable habitats across northern Sardinia, most coastal areas, surrounding small islands, and several inland mountainous sectors not yet colonized. In contrast, all future scenarios predicted strong range contraction, with climatically suitable habitat declining by 91.02–98.98% depending on scenario and time horizon, primarily through loss of coastal suitability. These projections suggest that future Mediterranean warming and altered precipitation regimes may progressively exceed the favorable climatic envelope of V. crabro , likely constraining rather than promoting its long-term persistence and spread in insular Mediterranean systems (Fig. 1). More broadly, our findings challenge the widespread assumption that climate change universally enhances invasion risk and highlight the need for species-specific, fine-resolution forecasting to support adaptive surveillance, prioritization, and management of invasive species under climate change. Beyond this case study, the proposed workflow demonstrates how citizen-science data, bias-aware pseudo-absence generation, spatially explicit validation, and ensemble forecasting can be integrated into reproducible invasion-risk assessment frameworks for operational decision support.

Plant–pollinator networks provide crucial insights into the mechanisms shaping the structure, stability, and ecosystem services of bee communities. Despite the Mediterranean basin being one of the world's richest regions for bee and plant diversity, it remains relatively understudied, with many islands largely overlooked in interaction studies. Here, we conducted an extensive survey of wild bees and their interactions with plants across four sites in Sardinia, the second–largest Mediterranean island, including two locations on Asinara Island with largely natural habitats and two sites in Nurra, a mainland area dominated by agroecosystems. In total, we recorded 122 wild bee species, including Hoplitis corsaria (Warncke, 1991), here reported for the first time from Italy, and six additional species newly recorded for Sardinia, highlighting the still incomplete exploration of the island's bee fauna. Bee diversity varied across sites, with higher richness at greater habitat heterogeneity, and at temporal scale, with consistent peaks of richness and diversity in May–July, likely according to variation in plant species richness but not in plant abundance. All bee–plant networks (divided by site and seasonal period) were highly specialized, modular, and non–nested, indicating low stability and potential vulnerability to disturbances. Network–level specialization, but not species–level specialization, varied among sites and also peaked in May–July, while marginally decreasing with plant species richness in the whole community. Since habitat heterogeneity was positively associated with percentage of both crop and urban cover, the observed patterns preliminarily suggested a role of anthropogenic disturbance on bee communities but not, or weakly, on network topology. Broader sampling across Sardinia will refine our understanding of habitat–driven effects.

The Mediterranean Basin is recognised as global biodiversity hotspot, with islands playing a crucial role in sustaining high levels of endemism due to their geological complexity, biogeographical history and habitat heterogeneity. Despite this, many Mediterranean islands remain underexplored from a faunistic perspective, particularly regarding nocturnal Lepidoptera. This study provides new faunistic data on the nocturnal macrolepidoptera of two protected areas in the north of Sardinia: Asinara and La Maddalena islands. A total of 875 specimens were collected, representing 98 species across four families. Of these, 62 species were recorded on the La Maddalena and 78 on the Asinara islands. Notably, nine species are newly reported for La Maddalena, increasing the known macrolepidopteran fauna of the archipelago. Our study provides novel insights especially to the knowledge of the Asinara Island which remains poorly investigated due to its historical restricted access. This study offers a baseline for future ecological and biogeographical research and highlights the need for ongoing faunistic surveys in Mediterranean island systems. Furthermore, this study underscores the biogeographical importance of these islands which host rich moth communities despite their small size.

Social insects employ venom as an external immune defence against pathogens and parasites. Like other Hymenopterans, the venom gland of honey bee (Apis mellifera) serves as a reservoir of antimicrobial substances, primarily melittin. This study investigated the presence and origin of venom on honey bee body that could act as an external immune defence in honey bee workers infested by the ectoparasite mite, Varroa destructor. Using a multi-step approach, we first confirmed the presence of venom on bees’ bodies using melittin as a marker. We then examined how grooming could facilitate the distribution of venom on the bee’s body through behavioural observations. Further assays were used to compare melittin levels on the bodies of Varroa-free and Varroa-infested workers and assess the effects of bee-venom on mite activity. Our findings confirmed the occurrence of “venom bathing” in A. mellifera, excluding social components or environmental contamination, with bees likely coating their bodies with antimicrobial substances through self-grooming. Our results further suggest that infested bees spread higher amount of venom on their bodies compared to uninfested bees, and bee-venom significantly reduced mite activity, suggesting that the venom functions as an external defence. However, Varroa negatively impacted melittin production. Our study reveals a previously unknown negative effect of V. destructor: impairment of honey bees’ external immune defence through reduced melittin production.

Animal medical systems encompass a wide range of behaviours aimed at maintaining or improving health. It has become clear that these behaviours are not limited to animals treating themselves (self‐medication) but also include the treatment of group members, resulting in the adoption of the more inclusive term “animal medication”. Behaviour with the intent to avoid, reduce the impact, or otherwise treat disease transmission, rather than the use of medicinal substances, can be described as medical behaviours . However, most behaviours described here involve the ingestion or application of items with medicinal properties to oneself or the application of items to others or their temporary or permanent communal living spaces like nests or burrows, hereto named medicinal or medication behaviours . This review begins with a historical overview of the field, showcasing an increasing awareness of the wide diversity of taxa exhibiting animal medication and elucidating the development of criteria used to define and categorise such behaviours across the animal kingdom. A thorough synthesis of recent research is presented, by providing critical reflection that challenges conventional notions and emphasises the significance of sociality and ecological context. To this end, medical systems are explored by using numerous examples, thus highlighting the diverse strategies animals employ to maintain health and improve fitness, ranging from honey bees foraging on antimicrobial resin to control hive disease to apes ingesting small amounts of toxic secondary compounds to control parasite infection. The understanding of how animals maintain their health through medical strategies offers valuable insights into the evolutionary origin and complexity of the drivers behind these behaviours. Evidence suggests that advanced cognition is not necessarily a prerequisite because innate mechanisms are likely involved in the expression of these behaviours across the animal kingdom. By highlighting the importance of life‐history traits and ecological context in predicting animal medical systems, we reassess the presumed primary drivers of these adaptations. Finally, this review raises important questions about animal medical systems, including the universality of the mechanisms involved, the evolutionary significance of parasite pressure, and the ecological implications of this suite of behaviours. By addressing these complexities, this review provides a nuanced understanding of animal medical systems and highlights avenues for future research in this field.