Let’s hear it for those randy ladybirds
A LADYBIRD might alight on an arm, to cling in a tinkling thrill, as a charmed child moved carefully to display one of nature’s surprises.
A ladybird is a shiny scarlet beetle with black spots, a tiny purveyor of joy universally attractive to children, an insect welcomed without the anxiety triggered by other aerial buzzers of summer days.
The ladybird logo has appeared on clothing, crockery, slippers and books, the image inextricably linked to a toddler’s world. It began with a brilliant idea for a book imprint in Loughborough, Leicestershire, by a man named Henry Wills, joined in 1904 in this enterprise by William Hepworth. Ladybird books still appear, augmented now by adult titles, under the umbrella of Penguin.
Ladybird insects — 19 species reckoned here with a sev- en-spot Coccinella the most commonly observed — are long livers (if not worn out by reproduction) and are tremendously useful in horticulture, feeding on aphids and mites, eating up to 50 a day.
They are safe from bird predators as they are evil-tasting and, if attacked, give off an unpleasant fluid. The insects hibernate under tree bark and in spring lay eggs under leaves and, after hatching, the grubs begin aphid feasting, pupate like butterflies and turn into ladybirds.
Warm summers should see lots of them about. (As readers have kindly notified, especially one north Leinster observer who has been counting yellowhammers!)
But there is a surprising side-story about the nurseryrhyme charmer whose name is believed to have some religious connotations — the Irish Bain De and Spanish Vaquilla de Dios translate as “God’s Little Cow”.
While most ladybirds gorge on aphids and some prefer plant mildew, they can also resort to cannibalism among young brothers and sisters when food stocks run low. But the real surprise in their varied spotted world is their wanton promiscuity, much of it unexplained.
Females may spread their favours widely for up to nine hours at a time, according to a genetic study at Cambridge University a decade ago. Dr Michael Majerus also found male insects were capable of producing multiple organisms which could damage their survival. He was reported as saying: “Ladybirds are lovely. Everybody loves them. But they are randy. The females are ridiculously promiscuous; the males unusually vibrant. We don’t know why they do it.”
He said, that by mating with a number of males, the females risked wasting some of their limited egg stock and also lost energy carrying males about. The male orgasm took more than an hour, “squandering” reproductive cells — the female’s maximum capacity was for 18,000 sperm and each male package contained about 14,000. There was something theoretically wrong about this, he added. Ladybirds were also one of the few insect species that carried a sexually transmitted disease.
Whatever about such extraordinary lives, ladybirds destroy great numbers of greenfly to the enormous benefit of plants. In California, ladybird ‘factories’ are vital in controlling insect attacks on citrus crops. The randy pet beetle saves millions of dollars.