How a Harlequin Ladybird got its Spots

29th August 2012
Apart from a few 2-spot Ladybirds (Adalia bipunctata) and a single 14-spot Ladybird (Propylea 14-punctata), all the ladybird activity I'm seeing in the garden at the moment is with the Harlequin Ladybird (Harmonia axyridis).

I've blogged about this ladybird before, but here's a repeat of the basic information. It spread to the UK from Europe in 2004 and has since expanded rapidly northwards, now covering most areas in England and Wales with sightings in Scotland and Ireland too. Its name comes from the fact that it exists in many colour forms (over 100 different colour patterns). Some specimens are reddish-orange with black dots, others black with red patches. They exist in three main forms; succinea, spectabilis and conspicua.

Unlike most other ladybirds, the Harlequin does not stick to one type of food. Once it has finished feeding on aphids, it then turns its attention to other ladybird eggs and larvae and even the eggs and caterpillars of moths and butterflies. The main reason Harlequin Ladybirds pose a threat to our native ladybirds, is that they have such voracious appetites that they easily out-compete native ladybirds for food. They have been described as "the world's most invasive ladybird".

I have seen the succinea form of the adult (reddish/orange with black spots) in the garden and recently some Harlequin larvae (image top left). These are large (the ones I've seen have been up to 10mm); black and orange, and very spiny. In the last week I've also started seeing pupae. These have been similarly coloured and have had the spiny, discarded larval skins underneath them. I couldn't think what it was the first time I saw one!

I thought it would be interesting to capture the moment when an adult ladybird emerged from a pupa. When I found one on a cherry tree leaf in the garden (image left), I decided to keep a close eye on it and checked on "progress" every day. On Monday when I looked, the pupa was empty and I thought I had missed my chance. Fortunately, under a hidden part of the leaf, I found the newly-emerged adult. It was still damp, its wings extended at the rear and pale orange in colour with no sign of any developing spots. I took a couple of photographs, and as the weather was chilly and blustery, cut off the leaf and brought it indoors so that I could observe what happened next.

At first, the ladybird dried off a bit and gradually started "retracting" its wings. This process was completed after about 45 minutes. After another hour, darker markings had started to develop and at 2 hours 40 minutes were quite obvious. These areas continued to darken and at 5 hours were virtually black. This is the typical spectabilis form; black with four large orange/red spots. I kept the ladybird overnight and then released it. At this point, the dark areas were fully black and the spots slightly more reddish.

You can get more information about Harlequin Ladybirds and record any sightings at the Harlequin Ladybird Survey website.


[Click on any of the 3 images above for a larger view]






Comments

Photo comment By Ron Bowden: Facinating to watch the miracle of change as it actually happened. As usual, brilliant photography.

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