Harlequin Ladybirds - Aggregation

[Bruce Williams]

I thought some members might be interested:

Stony Stratford, Bucks. 31st March 2011. Inside mouth of tunnel under the A5.

Approximately 250-300 individuals (the photo shows just a part of the total aggregation). There were maybe another 50 or so more, widely dispersed individuals within about a 3m radius of the main group. Quite a few were mating pairs.

Last summer I saw 1,000 or more in a loose aggregation covering the outside stonework of this same tunnel.



Bruce

[aeshna5]

I'm still only seeing occasional individuals (maybe many are still dormant?) compared with quite a few 7-spots most days when it's sufficiently warm.

[Paul mabbott]

I wonder if they';ve been in the tunnel over winter and have just warmed up sufficiently to emerge? Fascinating though.

[Bruce Williams]

Update: The core aggregation was still there this afternoon (photo taken 2 days ago) but many more dispersed inside and outside the mouth of the tunnel.

Aeshna - This afternoon I came across a group of about 40ish 7-spot ladybirds on a bottom rail of an old wooden fence about 100m from the tunnel wall - several couples were mating.

Paul - Could be - although I check this tunnel at least once a week they could well have been overwintering in the deep crack visible at the bottom of my pic.

Bruce

[Klaas Reißmann]

Hello everybody,

maybe I got aeshna's posting wrong, but there is no sevenspot on the photo. It is all Harmonia axyridis and only one that can bee seen by half of it, could possibly be Adalia bipunctata.

Regards
Klaas

[aeshna5]

Originally Posted by Klaas Reißmann

Hello everybody,

maybe I got aeshna's posting wrong, but there is no sevenspot on the photo. It is all Harmonia axyridis and only one that can bee seen by half of it, could possibly be Adalia bipunctata.

Regards
Klaas

You have indeed misinterpreted my post- perhaps I wasn't too clear!

My post was referring to my own observations locally + not identifying those in the photo which I took to be all Harlequins (though didn't study it too closely).

[Bruce Williams]

Klaas - Yes all Harlequins for sure .

Aeshna - I understood you were referring to your own observations - so no problems this end .

Bruce

[Bruce Williams]

FURTHER UPDATE:

Checked out the location again this afternoon. There's still a very large number of Harlequins in the crack. However the really interesting/surprising thing is the depth/width of the crack in the wall. It was hidden by ladybirds in my original pic however there were clear areas today and I was able to see that the crack is at least 4 inches deep - and the crack does not narrow appreciably as it gets deeper. I could see that in areas it was still full of ladybirds for the full depth of the crack.

I'm now absolutely certain that my original estimate of 250-300 was way under the actual number - I would say there were in excess of 500 individuals on 31st March.

I should make it clear that the crack is about 4 times longer than the section in my original photograph.

Bruce