Was the harlequin really bad news ?

[fairplay]

I am trying to find out if the Harlequin invasion of 2004 has had the serious impact on our native ladybirds as was predicted at the time ?
An amateur naturalist on the Suffolk coast claims to have been studying these Harlequins at a location for 7 years and says that they live 'harmoniously' with our native ladybirds.
Bewilderingly, he talks of a "great invasion into Norfolk followed by many sightings across the UK" even though it seems to be accepted the main invasion was at Essex and spread from there.

Officially, the first adult Harlequin was found Sunday 19 Sept 2004 in Essex by an Ian Wright and identified by the late Professor Michael Marjerus, but *Tony Irwin of Norwich Castle Museum announced on Nov 2 that he had taken a photo of a Harlequin larva racing around the rim of a flowerpot in his garden in July of that year.

This naturalist has gone on to claim that since he started studying the harlequins at his local patch in 2004 "Thankfully, numbers have remained steady with fewer than 30 adults and larvae found since"
Either this is a typo error, the guy just isn't looking, or else this has implications for the rest of the country.

So what is happening in your part of the country then - were they as destructive as first predicted, are they holding their own and living 'harmoniously' with the natives, or are they dying out ?

Neil.

* Tony Irwin is the Curator at Norwich Castle Museum and County Insect Recorder.

[Dogghound]

I first noticed them around here during the Autumn of 2008, in 2009 I knew of around three areas with decent sized populations, during 2010 number peaked in the summer then declined rapidly with the onset of winter and in 2011 appeared to have crashed as I only found 1 harlequin imago.

Anecdotally numers of other species have remained constant with no significant fluctuations.

[aeshna5]

This year I've noticed far fewer Harlequins in the autumn period where they were often abundant around west London. 7-spots have been high in number over at least the last 3 years.

Have to say my impression is that the dangers they pose have been somewhat hyped up as I haven't seen any obvious declines in other species locally. There do seem fewer 2-spots, but these had declined before the Harlequins arrived + many other factors such as habitat change, weather patterns, parasitism, disease, etc may all be factors too.

[Paul mabbott]

Originally Posted by fairplay

..........An amateur naturalist on the Suffolk coast claims to have been studying these Harlequins at a location for 7 years and says that they live 'harmoniously' with our native ladybirds.
Bewilderingly, he talks of a "great invasion into Norfolk followed by many sightings across the UK" even though it seems to be accepted the main invasion was at Essex and spread from there.

Officially, the first adult Harlequin was found Sunday 19 Sept 2004 in Essex by an Ian Wright and identified by the late Professor Michael Marjerus, but *Tony Irwin of Norwich Castle Museum announced on Nov 2 that he had taken a photo of a Harlequin larva racing around the rim of a flowerpot in his garden in July of that year.
...........

To clarify the issue, the bulk of early sightings were in Kent-Sussex and South London (some maps at Harmonia axyridis, the invasive harlequin ladybird (Coccinellidae) establishing in London, Essex and the UK) - the finds in Essex were patchier although the whole south-eastern English coast from Norfolk to Hampshire received some migrants. Many of the arrivals were wind-powered or came under their own steam but undoubtedly the Kent and London ones were assisted by ferries, trains and lorries!

[Geoff F]

In S, Devon I found the first one in 2010. Last year (it's almost 2012 now) I found a few more and at different locations. But, so far, never more than a couple in the same day.

[Klaas Reißmann]

My own experience:

In the first three years the harlequin is a problem to the native Coccinellidae. But during the years I noticed that there is the same number of the native Coccinellidae as it was the years before the harlequin.

Analysis in Germany showed, that the treatment of parasites, such as wasp and flies, but most of all Nematoda is very strong in the harlequins and keeps them in smaler numbers, even they are still very common.

Around ten years after infestation in northern Germany the sevenspot got an outbreak and was found in millions in the northern parts of Germany, such as you could see before the infestation of the harlequin.

I resume that the harlequin is no bigger problem. I can observe this since 2003 and I still find my native Coccinellidae with no problems.

Regards
Klaas

[fairplay]

Many thanks Klaas for that information, and many thanks to everybody else for the feed-back.

I think then, we can safely assume the expert/s in the UK got it wrong.
What I find surprising is when it was introduced into Germany and other countries to control pests, surely, especially Germany, would have done very thorough controlled tests before releasing the Harlequin and by the time it had reached the Nederlands, our own experts must have known there were no serious detrimental effects.

So when they finally did arrive in the UK, why did some put out these scare stories of the Harlequin eating all the aphids, cannibalising our own native ladybirds, and worse. It makes you wonder.

Neil.

[Jason Green]

Originally Posted by fairplay

I think then, we can safely assume the expert/s in the UK got it wrong.

So when they finally did arrive in the UK, why did some put out these scare stories of the Harlequin eating all the aphids, cannibalising our own native ladybirds, and worse. It makes you wonder.

Think of the impact the release of mink and arrival of grey squirrels have had on our native species. It's always best to assume there could be some detrimental impact when you put species together that haven't evolved together. Any stories fore-telling the dangers would simply be expecting it may happen as has already happened in the two species I mentioned. They'll be only too pleased though if the introduction hasn't turned out how they thought it may. It's of course early-days, we certainly can't draw conclusions after just 8yrs. The Netherlands may have some experience on ours, but of course there are other differences between. Out of interest, can you recall the name any of the UK experts who have said to this effect? You know, off the top of your head.

H. axyridis certainly had the ability to spread rapidly, quite correct were those said they would. That won't have helped people think it'll just happily 'ingratiate', either. I once saw a group of five harlequin larvae canabalising a pre-putating one. Quite creepy to see it wriggling to get away but being unable to go anywhere! I think I have a photo of that somewhere somewhere, actually.

[Meta menardi]

Originally Posted by fairplay

Many thanks Klaas for that information, and many thanks to everybody else for the feed-back.

I think then, we can safely assume the expert/s in the UK got it wrong.
What I find surprising is when it was introduced into Germany and other countries to control pests, surely, especially Germany, would have done very thorough controlled tests before releasing the Harlequin and by the time it had reached the Nederlands, our own experts must have known there were no serious detrimental effects.

So when they finally did arrive in the UK, why did some put out these scare stories of the Harlequin eating all the aphids, cannibalising our own native ladybirds, and worse. It makes you wonder.

Neil.

I think it takes more time than we have had so far to pronounce the effect understood. A non typical cold winter may have helped, and many other things need to work out through an ecological system before we can know what is going on.

On a lighter note, more money should be spent on research (it used to be a funny thing to say, but now no money is spent on research, the joke is a little dry).

Why did the beast spread so quickly and seem so abundant? I found it all over the place, and now can't find it. Are we going to have boom and bust years (not unknown with new species)?

[Meta menardi]

Jason, you were tippy tapping whilst I was tappy tipping.