Harlequin Ladybird Introduced Species

I find myself thinking a lot this week about introduced species. When I say 'introduced' species, I mean non-native ones intentionally or unintentially introduced into an area by people. I think this topic is on my mind due to the number of harlequin ladybirds (Harmonia axyridis) I'm finding in my garden this autumn. This species was purposefully introduced to  mainland Europe from Asia as biological pest control. It was released in France in 1982 for this purpose.

I took all the photos above over the past couple weeks in my back garden among the raspberry patch mostly. I wanted to capture the amazing variety of colour variations within this one species. 

These little insects are largely welcomed in my garden as they keep down the aphid population, but they are a species I simultaneously look upon with a degree of unease. This is because they are viewed by many as not just an introduced species but also a vilified invasive one on our shores.

It was first recorded in the United Kingdom in 2004 and is now found throughout England and Wales as well as in parts of Scotland. Reading the literature, there is strong evidence harlequin ladybirds are competing with our native ladybird species. Our native species are seeing dramatic declines in areas where harlequin ladybirds are rapidly increasing. It is hypothesised this is due to harlequin ladybirds not only competing for the same food sources, but also actually predating our native ladybirds.

Harlequin ladybirds are clearly here to stay and like all invaders of this kind will eventually, one way or another, come into equilibrium within our ecosystems. Unfortunately, this process could lead to the decline or even demise of other species along the way. In the case of harlequin ladybirds, it looks like the loosers will most likely be some of our native ladybirds. This is a rather depressing thought...

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