One topic that I have had a specific interest in has been invasive species. They are a phenomenon that I only became aware of in the last few years, and since then I have been attempting to educate myself about the impact they are having on biodiversity.
The first invasive species that I (knowingly) came across was the Harlequin Ladybird (Harmonia axyridis). I first encountered one in Cork City about 5 years ago. I was walking for my bus and had stopped to put some rubbish in a bin, only to find a bright red, heavily spotted lady bird walking along the adjacent wall. At the time I thought it was a native ladybird species that I was unfamiliar with, so I took a picture so as to identify it properly when I arrived home. Some quick googling indicated that this the non-native and high impact species that arrived in Ireland in 2010.
This ladybird species originates in Asia, and was introduced to Europe as a biological control as an attempt to control aphids in agricultural crops in the 1980s, and it is thought to have arrived in Ireland sometime around 2010. It turns out that these ladybirds are incredibly competitive and aggressive. Studies from the UK show that they have voraceous appetite and will eat pretty much everything…including native ladybird species. In the UK, this invader is thought to be responsible for a 44% decline in numbers of the native 2-spot ladybird.
Here in Ireland, they are spreading rapidly and they have a strong presence in and around Cork City. I believe that there are far more widespread and numerous than what is shown in the distribution map shown here. This little critter is recognised as one of the world’s fastest invasive species, it has taken just a few short years to colonise most of Britain. It stands to reason that they are spreading just as rapidly here. Also, because this species is so variable, they can easily be confused with many of our native species, so people may not actually recognise this invader for what it is and confuse it for a native ladybird.
I would encourage anyone who comes across a ladybird (native or otherwise) to submit your sighting to the National Biodiversity Data Centre. By submitting such records, you can hep scientists here in Ireland to map the distribution of our natives and help scientists to map the spread of the Harlequin.
For more information on the Harlequin Ladybird please follow the links below: