A-Z of nature:
Dr Ben Aldiss on the little spotted wonder many know in Norfolk as a bishy barnabee
It’s L for... bishy barnabee
Lstands for Ladybird in this month’s look at the Nature of Norfolk, but I’ll take the opportunity to delve into the world of other beetles too.
I was lucky enough to be a student of ecology at Royal Holloway College at the same time as Mike Majerus, who later became Professor of Evolution at Cambridge University. As we were both fascinated by insects, we studied entomology as one of our modules, then went our separate ways to do research. Years later we met again as guest speakers on a conference about invasive species. I spoke about wasps and he followed with a talk on the harlequin ladybird. Sadly, he died aged only 55, but his legacy as a ladybird expert lives on.
Ladybirds are beetles and belong to the family Coccinellidae. The word means scarlet and comes from the Latin description of the colour of the familiar seven-spot ladybird. There are around 3,500 species known to science, only 46 of which are found in Britain. Of these, 26 are instantly recognisable as ladybirds and we have 21 of them in Norfolk. As a schoolboy, I knew them by their Norfolk name of bishy barnabees, apparently after the notorious 16th century Bishop Bonner and his red cloak.
All bar three of our ladybirds feed almost exclusively on aphids, so they’re very welcome in the garden if your roses are infested with greenfly. The other three are herbivores, feeding on moulds, pollen or leaves. One of these vegetarians – the russetorange 24 spot ladybird – has arguably the longest Latin name of any animal: Subcoccinella vigintiquatuorpunctata.
Apart from their occasional influx in huge numbers from the continent on to Norfolk beaches, ladybirds have enjoyed a good reputation, but things have changed since the arrival of the notorious harlequin ladybird. Named after its huge variety of colours and patterns, it’s also called the Asian ladybird or, in the USA, the halloween
ladybeetle, as it tends to invade homes in late October to hibernate. Hundreds have recently emerged from their winter sleep in our house in north Norfolk.
The harlequin ladybird has spread throughout the world from its home in Eastern Asia as a result of uncontrolled introduction by market gardeners for its efficiency in controlling scale-insects and aphids on greenhouse crops. Being generally larger and more aggressive than our native species, the Harlequin not only competes for food, but will eat other ladybirds if the aphid supply runs out, so it’s a genuine threat to the other 21 kinds living in Norfolk. As if that’s not enough, it has been known to bite and – like other ladybirds – it can exude a foul-smelling, yellow fluid from its leg joints by a process known as reflex bleeding.
There are two other beetles
I want to discuss in this look at the nature of Norfolk. Both are impressive and can be found in various parts of the county if you look carefully in the right places. The first is the glow-worm. It gets its name from its two most obvious features: the female is long, flightless and wormlike and she has the ability to glow with a greenish light at her rear end. The male is everybody’s idea of a standard beetle, being small and brown with hard wing cases.
The glow-worm’s life-cycle is a fascinating one. In the months of June and July on calm, warm summer’s evenings, the female creeps out of shelter in grassy areas at the edges of her woodland or hedgerow habitat to signal her intent to mate. Males flying at the same time are attracted to the steady green light she emits from a special chemical reaction taking place in the segments at the end of her abdomen.
This reaction produces light with very little energy wasted as heat, so she can glow for up to two hours a night for ten consecutive days, all without food, as apparently the adults don’t feed.
If a male spots her he immediately flies towards the light to mate. Bigger females produce brighter light, so they’re more likely to attract a male. The female then switches off her light and eventually lays tiny eggs that glow faintly yellow. The grubs or larvae that hatch from these eggs look similar to the adult female as they grow bigger. They can also glow, but only from twelve tiny spots down their sides, rather than the big light-show provided by their mother.
The diet of the glow-worm larvae is unusual and rather gruesome. They feed on live slugs or snails that may be up to 200 times heavier than themselves.
Creeping up on damp nights under the cover of darkness, they locate their snails or slugs by scent, then bite them to inject a mixture of poison and digestive enzymes. The ill-fated molluscs then become paralysed, after which, depending on their size, some or all of their juices are sucked out.
Amazingly a few survive this treatment and survive to live another day, despite being rather slimmer than before.
I was going to speak of another fearsome carnivore – the formidable great diving beetle – but it’s occurred to me that I’ve talked about predators for three weeks running, so I’ll end on an altogether more gentle note instead and tell you about the bloody nosed beetle. I’m sure you’re thinking that this is yet another pugnacious meat-eater that keeps getting into fights, but you’d be wrong. It’s actually
a lumbering and rather comical herbivore that wouldn’t hurt an aphid or a snail. In fact it happens to be a family favourite of ours, eagerly looked for on sunny days in grassy meadows and hedgebanks, where it feeds exclusively on bedstraw. A ponderous, shiny blue-black beetle, it has six rather long legs ending in sticky feet that look like big hob-nailed boots.
Not only is it slow, but it’s lost the power of flight, so it would appear to be the perfect snack for any passing carnivore. But no – it has a couple of tricks up its six metaphorical sleeves.
Spiders and other arthropod predators stand no chance, owing to the incredibly thick armour that covers the beetle’s entire body. You may think that birds and mammals would fare better, but just as they’re about to take a bite, the beetle plays its second trick and spews a large blob of bright red, bitter liquid from its mouth, giving a very passable impression of a bloody nose.
Not only is this visually startling, but one taste and the predator learns never to mess with this creature any more.
There are more species of beetles in Norfolk than any other insect, so I’ve hardly done them justice, but there may yet be a chance to revisit them before we reach the letter Z.
‘The diet of the glow-worm larvae is unusual and rather gruesome. They feed on live slugs or snails that may be up to 200 times heavier than themselves’
ABOVE: The invasive harlequin ladybird munching through some aphids BELOW RIGHT: The familiar seven-spot ladybird
ABOVE: A bloody nosed beetle spews a large blob of bright red, bitter liquid from its mouth to deter predators if attacked