Honey bees play an important role in agricultural landscapes by providing pollination services. Throughout the season, colonies increase their population and collect resources from the available flowering plants. Besides internal mechanisms, such as the amount of brood or the availability of bees to perform foraging flights, colonies are also influenced by the climate and the surrounding landscape. Therefore, exposure to different environmental contexts leads to distinct development rates. In this study, we show how colonies develop under three different landscape contexts and explore which external variables (mostly climate and resources availability) influence the colonies’ development. We installed three apiaries in three different landscapes in the Iberian Peninsula, with temporal and spatial variation in climatic conditions and resource availability. The availability of resources and their use, as well as the development of colonies throughout the season, were thoroughly investigated. These data were used to take the first step into creating an ecologically relevant landscape by calculating the number of available resources in the landscape at different points in time, based on plants’ beekeeping interest as well as nectar and production. Furthermore, climatic variables were transformed into the amount of available foraging minutes that bees had to collect resources, and a theoretical threshold of optimal vs. sub-optimal conditions was also explored. Interestingly, the main drivers of colony development (measured by daily weight increase) were not the same in the tested apiaries, evidencing how colonies are indeed intrinsically connected with the surrounding environmental scenario. Therefore, results from field testing are extremely context-dependent and should be interpreted with caution when being extrapolated to other environmental scenarios.

The yellow-legged hornet, Vespa velutina subs. nigrithorax Buysson, 1905, is an invasive species in Europe, posing substantial ecological and economic threats. Its biology and behavior, marked by rapid reproduction and aggressive predation, endanger native insects. This has negative impacts on agriculture, biodiversity, and human safety. Effective control is therefore essential to prevent and minimize its spread and ecological impact. This study assessed the acute oral toxicity of four commercial insecticide formulations containing acetamiprid, spinosad, cypermethrin, and a mixture of natural pyrethrins as active ingredients on V. v. nigrithorax workers. Our findings indicate that acetamiprid and spinosad are the most promising compounds, with acetamiprid inducing rapid mortality at low doses, and spinosad causing both lethal and sublethal effects, potentially disrupting hornet behavior and colony viability. Given that oral exposure generally resulted in higher toxicity than contact exposure, pest control strategies should incorporate multiple exposure pathways. Further investigations are necessary to confirm efficacy under field conditions and to evaluate potential ecological risks to non-target species. Overall, this study provides critical data to improve V. v. nigrithorax control and supports the development of more effective and environmentally sustainable control strategies against this invasive species.

Standardized laboratory assays are essential for generating reproducible and comparable data in toxicology. Although acute contact and oral toxicity tests are widely applied in pesticide risk assessment, these approaches have rarely been adapted for social vespids. Vespa velutina nigrithorax, an invasive hornet in Europe and East Asia, is commonly managed through chemical control, yet treatment efficacy may vary depending on the route of exposure and other biological factors. This protocol describes a standardized method to assess acute contact and oral toxicity of chemical compounds in adult V. v. nigrithorax workers under controlled laboratory conditions. Hornets are collected in the field, individually housed, and exposed either to topical applications on the thorax or to spiked food sources. Mortality is monitored over 48–96 h and analyzed using appropriate statistical approaches to estimate lethal endpoints. This protocol enables comparison among compounds and exposure routes and provides a practical framework for toxicity screening in hornets.