A report has been published on the genetic analysis of the Asian Hornet nests found in both Ireland and Northern Ireland during 2025.
Project aims
The aims of the analysis were:
Aim 1: To understand the origin of the Irish nests, namely whether they derive from the secondary invasive population present in Europe, or whether they are independent arrivals from elsewhere (likely Asia).
Aim 2: To understand the relatedness of any recovered individual ‘lone’ hornets from Cork, Cobh or Belfast to the recovered nests, i.e. to understand whether all the lone hornets found locally derive from the nearby nest; if they do not, this is a strong indication that these individuals are from a different nest(s) that were not detected locally.
Aim 3: To ensure that the genetic data is appropriately stored to freely inform future research on this species either in Ireland or internationally.
Aim 4: To understand whether the nests were destroyed before they had moved into the reproductive phase, i.e. whether the queens of the nests had started laying haploid drones and at which life stage.
Aim 5: To understand if any other genetic effects were present in the nest, such as: diploid (sterile) males; triploid individuals; the presence of worker laying (which cannot give rise to nests in the next year).
Diploid males are the likely result of an error in the sex-determining mechanism, made more common by low population genetic diversity and inbreeding.
Summary results
Origin of Irish individuals
All hornets sampled were highly likely to derive from the European Asian hornet population.
Lone hornets and possible presence of further nests
All lone hornets recovered (near the Cork and Cobh nests) were highly likely to derive from the nest they were caught near to. There was no evidence of additional nearby nests.
Potential for nest reproduction (Aims 4 and 5)
Cork: It is highly unlikely the nest had produced adult males or future unmated queens.
Cobh: If potential future unmated queens have been produced, this is likely to be a low number. The expected risk of more than a small number of mated, overwintered queens can be considered very low.
Belfast: The nest had produced adult males and was likely to have started producing potential future queens, a small proportion of which may have reached adulthood. This is consistent with the relatively late date of destruction of this nest (18/10/2025)
You can review the final report below: