No fly zone

by Richard Jones

On Saturday I turned over a rose leaf to reveal a bizarre furry blob - the wingless female of the vapourer moth, Orgyia antiqua.

Adult female vapourer moth, and eggsOn Saturday I turned over a rose leaf that appeared to be stuck up with a mass of silky threads to reveal a bizarre furry blob - the wingless female of the vapourer moth, Orgyia antiqua. Well, she's not completely wingless, she has tiny vestigial stubs, but she is still quite unable to fly. Instead, she emerges from her cocoon and gives off a pheromone scent to attract the night-flying males. These rather unassuming moths are mottled brown with a small white spot on each forewing. She mates and lays her pale beige marshmallow-shaped eggs (I estimated about 250), and that's it. Job done.

Like most insects, her adult life is very short and with only one aim: to start off the next generation. This was only the second female I've ever seen, the first was earlier this year when I reared one from a larva. They must, in fact, be very common, because the caterpillars are all over the place. These spiky psychedelic toothbrushes are unmistakable, with their four dorsal tufts of bright yellow bristles and sweeping grey and black whiskers at both head and tail ends. They'll eat almost anything, even tough poisonous cherry laurel.

And that's the other thing about most insects, it is the larva that is the long-lived stage, spending weeks, months or even years eating and growing until just large enough to transform into the fleeting adult.

Although I find them regularly, I've never seen vapourer caterpillars in any great numbers, but according to several of my moth books they can occasionally be so numerous as to defoliate small trees. I have enough trouble keeping the rose sawfly caterpillars at bay, so I've moved Mrs vapourer and her brood to the end of the garden. Perhaps they can attack the bramble that grows over the fence from next door and threatens to engulf the shed each year.

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Gardeners' World Web User 04/11/2007 at 13:22

Yes, they certainly can defoliate small trees - the psychedelic toothbrushes did just that to my Kilmarnoch willow! I was less kind than you, and sent them to toothbrush heaven.

Gardeners' World Web User 04/11/2007 at 22:05

Reply to Frieda: There are several British moth species with wingless (or at least flightless) females, and for some reason most of them seem to come out in the winter. There's the vapourer, of course, the scarce vapourer (which is scarcer), the March moth (appears in March), the winter moth (appears in winter), northern winter moth (lives up north), small brindled beauty, pale brindled beauty, Rannoch brindled beauty (but not the very closely related brindled beauty, which has fully winged females), belted beauty, spring usher, scarce umber, dotted border, mottled umber and early moth. These are not all closely related species, so it seems that flightlessness has evolved several times across the Lepidoptera.

Gardeners' World Web User 04/06/2008 at 22:33

These caterpillars have been stripping the roses in the gardens where I work. I was pleased to see them at first but the roses were skeletal by the end of summer. I don't use sprays so I've been squashing them as soon as I see them this year but would prefer to deter them if possible. Any suggestions?

Gardeners' World Web User 19/04/2010 at 14:38

I have a 4ft high laurel planted last autumn and it is being eaten by something. It sounds like one of the moths I've just been reading about but I can't see anything apart from huge holes and half leaves missing. What can I do? I don't want to destroy moths or butterfly larva. Should I spray and with what??

Gardeners' World Web User 06/07/2010 at 16:32

At the Nurseing home my wife is at they have an internal courtyard to a three storey building, i.e no birds drop in. So a host of Vapourer caterpillars are devouring the trees, bushes etc, any hints to remove these toothbrushes?

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