Letter to the Editor: Ladybird Aggregation

The strange way in which ladybirds (perhaps millions of them) gather in a hydro power station on Tasmania’s isolated west coast.

From time to time we hear of insect aggregations — butterflies, beetles, spiders, bugs, etc. — sometimes apocryphal, sometimes with a scientific explanation, sometimes not. The breeding cycle of many butterfly species, Birdwing and Ulysses, for example, are pretty well documented.

The same can be said for Harmonia conformis, the common spotted ladybird that features in this ABC News article. I’m no entomologist but do know that ladybirds need a skin change between pupal and adult stages and, perhaps, during adulthood.

As they live for about two months and eat huge numbers of aphids — everyone’s favourite garden friend, along with spiders — is it possible a second shedding is needed, especially among the females? Is this the reason for the large numbers mentioned in the attachment? Or is it because they’ve come together at the end of their life cycle and reproductive span to die en bloc?

Isn’t life interesting?

Sincere thanks to ABC News Tasmania for their report.

Do you live somewhere that insect species aggregate? Tell us your experiences. Oh, and if you have a definitive answer to the riddle posed in the article, please do tell…

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