Vespa velutinanest distribution at a local scale: An 8‐year survey of the invasive honeybee predator

Abstract

Vespa velutina is an invasive species that was observed for the first time in France and Europe in 2004, which rapidly threatened domestic honeybees with active predation. For the first time in this study, we analyzed the distribution of V. velutina nests at a local scale to understand the pattern of nesting, and in 8 years of monitoring, a total of 528 nests were surveyed. With the exception of 2 years, the nests of V. velutina were randomly distributed within the monitored area, which suggested that intraspecific competition for nesting sites and/or food was unlikely. When the data for all years were combined, an aggregated distribution of nests at the seafront in the vicinity of the oyster farm and sportfishing activities was observed. This distribution suggested that seafood, attractive to vespids, might provide a valuable alternative food source that favored colony development. We also tested the effect of spring queen trapping of V. velutina on the distribution of nests in 2014, which was the year with the greatest number of colonies within the area; the position of the traps did not influence the distribution of the nests. For the first time, this study showed that (i) intraspecific competition was unlikely to be a mechanism for population regulation, (ii) some areas were more likely favored for hornet nests, and (iii) spring queen wasp trapping was inefficient as a method to limit the distribution of the V. velutina population.

Spread of the invasive yellow-legged hornet Vespa velutina (Hymenoptera: Vespidae) in Italy

“…only for 14.5 km and at less than 1,500 m for 42.8 km, therefore the species entered Italy through a narrow corridor close to the seaside. This corridor is also highlighted in the climatic model presented by Rome et al (2011) and the coastline could be considered a preference pathway of expansion, due to the presence of many food resources (Monceau and Thiéry 2016). Human-mediated transportation of animals could help the species overcome bottlenecks in the landscape; however, till now long distance movements have led the species to unsuitable areas in Piedmont or along the corridor close to the seaside in Liguria.…”

“…Observations of the yellow-legged hornet were reported by public warnings of beekeeper associations, local authorities and general public; in addition observations have been collected since 2015 by a monitoring team involved in the field survey. The team monitoring activities were fundamental to discover nests farther away from urban areas; in fact, most of the observations reported by the general public might be correlated with human activities (Monceau et al 2014, Monceau andThiéry 2016). The observations reported by the public were considered if they were verified by experts or accompanied by photographic documentation, given the possibility of misidentification .…”

Searching for nests of the invasive Asian hornet (Vespa velutina) using radio-telemetry

“…Governments and beekeepers across the EU are looking for methods to slow the spread of this pest species and scientists have documented the urgent need for research on early nest detection 19, 41 . Nest density in Andernos-les-Bains, France, rose from zero to 12.3 km −2 within 10 years 42 (although this included embryo nests which subsequently may not have reached maturity) and, with no control, Keeling et al 18 predict that there will be over 50,000 nests across England and Wales within 10 years, reaching carrying capacity in 20 years. So, while these predictions could be interpreted as a worst case scenario, they indicate that speed of action is critical.…”

Activity rhythm and action range of workers of the invasive hornet predator of honeybees Vespa velutina, measured by radio frequency identification tags

“…This information could help finding colonies and give a scale for potential control methods application. However, only models concerning nest distribution are available (Bessa, Carvalho, Gomes, & Santarém, 2016; Franklin et al., 2017; Monceau & Thiéry, 2017; Robinet, Suppo, & Darrouzet, 2016; Villemant et al., 2011). Risk assessment that integrates the action range of V. velutina is still missing but is unavoidable to progress in the management of this alien predator.…”