For a few years I have been monitoring the Ladybird population in a nearby park, in particular the growth of the alien Harlequins which have increased dramatically these last few years and who are having a huge impact on our native Ladybird specis which as I have noted is reflected by their decline in this area (the Midlands).
The late wintery weather we experienced this spring (2013) has also caused a decline in the insect populations, but the sturdy Harlequins soon recovered, not so our native Ladybirds.
The once common Seven Spot has been rarely sighted this year and it’s the same for the Two Spot, the Ten Spot and the Cream Spot which were all common back in 2012. Of the four types of Harlequins, three types are common in this area: Harmonia axyridis f.conspicua, f.spectablis and f.succinea, the latter being the most common with a ratio of 10:1.
Another observation I have made is the canalablistic traits of the Harlequins. In their larvae form they will eat their own and our native ladybird larvae and they are also fond of ladybird eggs, which must have also decreased our native specis.
Also the sturdy Harlequins are capable of surviving our winters even into the depths of winter as I have observed them in clusters on the underside of metal railings.
Hopefully the glorious summer we have had this year will give our native Ladybirds a chance to recover, Harlequins permitting.