Thursday 19 September 2019
On Tuesday 17th September, the Asian Hornet Team dissected the nest that was found in St Saviours earlier this month.
The nest was 30cm/1ft in diameter and consisted of 3½ combs containing eggs, larvae and sealed pupae (immature form between larva and adult). The largest individual comb was 18cm in diameter and was estimated to contain 444 cells. The total number of cells in the nest combined equates to the number of adult workers that would have been raised at that time. It is estimated that this colony would have been around 1500 at its peak.
Autumn is when the colony reproduces by raising fertile males, and females who will become queens of the new colonies next spring. These males and queens are normally produced from mid-September to the end of November and a large nest can create 300 new queens in a season. The longer the warm weather continues, the more males and queens reach maturity. They will spend a few weeks in the nest before they disperse which is why the race is on to find and destroy nests in the autumn before the hornets have a chance to produce the next generation of queens.
The dissection revealed that there were no signs of queens or males being raised when the nest was removed. This is an important discovery as the absence of queen Asian hornets at this time of year would mean none have departed from the nest and headed off to hibernate during the winter months.
Residual trapping around the nest site produced only two more workers over the weekend which are likely to have been stragglers from the treated nest that was taken down. All available evidence suggests that there isn't another nest in St Saviours. In 2018, the last sightings of hornets were at the end of October which is to be expected with the temperature dropping as autumn advances. However, there is always the possibility that migrating queens might find their way to Guernsey from France and neighbouring islands. The Asian Hornet Team are requesting that the public continue to be vigilant, and report any sightings.
A dedicated Asian Hornet Team Facebook page was recently established in order to provide regular updates and information to the community. Go to www.facebook.com/asianhornetguernsey to like and follow the page.
