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- Invasive hornets on the road: motorway-driven dispersal must be considered in management plans of Vespa velutinaPublication . Verdasca, Maria João; Rebelo, Hugo; Carvalheiro, Luisa; Sampaio e rebelo, RuiUnderstanding the mechanisms that potentiate the dispersion of an invasive species is essential to anticipate its arrival into new regions and to develop adequate management actions to minimize damage to biodiversity and society. One of the most successful invaders in Europe, the yellow-legged hornet (Vespa velutina), is dispersing through self-diffusion and jump dispersal. Using information on species occurrence in Portugal from 2013 to 2018, this study aimed to understand the range expansion trajectory of V. velutina and to identify the role of climate, landscape and anthropogenic variables on the two mechanisms of spread. We found that in Portugal the invasion is proceeding faster southwards (45 km/year) along the Atlantic coast than eastwards (20 km/ year) where the climatic suitability gradient is more compressed, with jump dispersal playing an important role in this difference and in the acceleration of the invasion process. Dispersal by diffusion was best explained by the annual range of temperature and precipitation of the wettest month, with distance to shrub land also having an important role. Additionally, jump dispersal appeared to be facilitated by motorways, hinting at the role of human-mediated dispersal. Indeed, the number of nests that resulted from this dispersive mechanism were significantly closer to motorways than expected by chance. To prevent the dispersal of V. velutina into Mediterranean regions, and in addition to a special attention to the advancing front, early monitoring programs should also target a buffer zone on both sides of motorways, and at freight shipping hubs.
- A metabarcoding tool to detect predation of the honeybee Apis mellifera and other wild insects by the invasive Vespa velutinaPublication . Verdasca, Maria João; Godinho, Raquel; Rocha, Rita Gomes; Portocarrero, Marco; Gigante Carvalheiro, Luísa; Sampaio e rebelo, Rui; Rebelo, HugoThe invasive Vespa velutina has been widely referred as an effective predator of honeybees. Despite the potential risk to pollination services provision and honey production, there is no accurate quantification and assessment of its real consequences for honeybees. To date, the identification of the honeybee and other insects in the diet of V. velutina has been investigated by direct observation of adult foraging or examination of food pellets. To overcome these limitations, in this study we used a DNA metabarcoding approach to evaluate the usefulness of different types of sample (jaws and stomachs collected from workers and larval faecal pellets taken from the hornet comb) to investigate the predation of V. velutina upon honeybees, and potentially on other insects. Honeybee DNA was identified in all types of samples, but larval faecal pellets retrieved the higher number of reads of honeybee DNA and the largest diversity at all taxonomic levels. Over all samples we could identify 4 orders, 9 families, 6 genera and 1 species of prey. We estimate that collecting 6 workers is sufficient to identify honeybee predation by a colony using worker’s jaws. Stomachs were the least useful sample type to detect honeybee DNA. The presence of honeybee DNA in all analysed colonies irrespective of collection site, and the variety of insect orders detected in the diet support current concerns over the acknowledged negative impact of V. velutina on managed honeybees and its potential threat to pollination services provision.
- Invasive hornets on the road: motorway-driven dispersal must be considered in management plans of Vespa velutinaPublication . Verdasca, Maria João; Rebelo, Hugo; Carvalheiro, Luisa; Sampaio e rebelo, RuiUnderstanding the mechanisms that potentiate the dispersion of an invasive species is essential to anticipate its arrival into new regions and to develop adequate management actions to minimize damage to biodiversity and society. One of the most successful invaders in Europe, the yellow-legged hornet (Vespa velutina), is dispersing through self-diffusion and jump dispersal. Using information on species occurrence in Portugal from 2013 to 2018, this study aimed to understand the range expansion trajectory of V. velutina and to identify the role of climate, landscape and anthropogenic variables on the two mechanisms of spread. We found that in Portugal the invasion is proceeding faster southwards (45 km/year) along the Atlantic coast than eastwards (20 km/ year) where the climatic suitability gradient is more compressed, with jump dispersal playing an important role in this difference and in the acceleration of the invasion process. Dispersal by diffusion was best explained by the annual range of temperature and precipitation of the wettest month, with distance to shrub land also having an important role. Additionally, jump dispersal appeared to be facilitated by motorways, hinting at the role of human-mediated dispersal. Indeed, the number of nests that resulted from this dispersive mechanism were significantly closer to motorways than expected by chance. To prevent the dispersal of V. velutina into Mediterranean regions, and in addition to a special attention to the advancing front, early monitoring programs should also target a buffer zone on both sides of motorways, and at freight shipping hubs.
- A metabarcoding tool to detect predation of the honeybee Apis mellifera and other wild insects by the invasive Vespa velutinaPublication . Verdasca, Maria João; Godinho, Raquel; Rocha, Rita Gomes; Portocarrero, Marco; Gigante Carvalheiro, Luísa; Sampaio e rebelo, Rui; Rebelo, HugoThe invasive Vespa velutina has been widely referred as an efective predator of honeybees. Despite the potential risk to pollination services provision and honey production, there is no accurate quantifcation and assessment of its real consequencesfor honeybees. To date, the identifcation of the honeybee and other insects in the diet of V. velutina has been investigated by direct observation of adult foraging or examination of food pellets. To overcome these limitations, in this study we used a DNA metabarcoding approach to evaluate the usefulness of diferent types of sample (jaws and stomachs collected from workers and larval faecal pellets taken from the hornet comb) to investigate the predation of V. velutina upon honeybees, and potentially on other insects. Honeybee DNA was identifed in all types of samples, but larval faecal pellets retrieved the higher number of reads of honeybee DNA and the largest diversity at all taxonomic levels. Over all samples we could identify 4 orders, 9 families, 6 genera and 1 species of prey. We estimate that collecting 6 workers is sufcient to identify honeybee predation by a colony using worker’s jaws. Stomachs were the least useful sample type to detect honeybee DNA. The presence of honeybee DNA in all analysed colonies irrespective of collection site, and the variety of insect orders detected in the diet support current concerns over the acknowledged negative impact of V. velutina on managed honeybees and its potential threat to pollination services provision.
- A metabarcoding tool to detect predation of the honeybee Apis mellifera and other wild insects by the invasive Vespa velutinaPublication . Verdasca, Maria João; Godinho, Raquel; Rocha, Rita Gomes; Portocarrero, Marco; Gigante Carvalheiro, Luísa; Sampaio e rebelo, Rui; Rebelo, HugoThe invasive Vespa velutina has been widely referred as an effective predator of honeybees. Despite the potential risk to pollination services provision and honey production, there is no accurate quantification and assessment of its real consequences for honeybees. To date, the identification of the honeybee and other insects in the diet of V. velutina has been investigated by direct observation of adult foraging or examination of food pellets. To overcome these limitations, in this study we used a DNA metabarcoding approach to evaluate the usefulness of different types of sample (jaws and stomachs collected from workers and larval faecal pellets taken from the hornet comb) to investigate the predation of V. velutina upon honeybees, and potentially on other insects. Honeybee DNA was identified in all types of samples, but larval faecal pellets retrieved the higher number of reads of honeybee DNA and the largest diversity at all taxonomic levels. Over all samples we could identify 4 orders, 9 families, 6 genera and 1 species of prey. We estimate that collecting 6 workers is sufficient to identify honeybee predation by a colony using worker’s jaws. Stomachs were the least useful sample type to detect honeybee DNA. The presence of honeybee DNA in all analysed colonies irrespective of collection site, and the variety of insect orders detected in the diet support current concerns over the acknowledged negative impact of V. velutina on managed honeybees and its potential threat to pollination services provision.