And Suddenly They're Here

AND SUDDENLY, THEY'RE HERE WILFRID S.

GEORGE

UNEXPECTED guests take everyone by surprise, now and again, and the naturalist probably greets them as frequently as anyone eise, often to his great pleasure, and always to his interest.

Sometimes they arrive spectacularly, like the ladybirds (Coccinellidae) did in 1961, or the hover-flies (Syrphidae) in 1960.

In these two cases, millions upon millions of the beetles, and of the flies, flew onto gardens, into houses, or drowned along the coast.

Seaside comedians cracked ladybird jokes, and newspapers reported the " striped flies ", while the public asked " where have they all come from ? ". Being most noticeable on the coast, we assumed they had migrated from the Continent, the result of over-production in the Common Market.

But what of the wasp plague of 1959 ? They were presumably locally produced stock, but it was hard to see why the queens had done so exceptionally well that year.

More frequent are the sudden billions of " thunder-flies " (minute rove-beetles) which appear several times during any normal summer. They have me puzzled, and my friends scratching.

Greenfly appear likewise, and their fast breeding is blamed.

Less often do the butterflies and moths appear by the million, (at least, not in Suffolk). Yet the cabbage white butterflies (Pieris brassicae, L., P. rapae, L.) migrate here from time to time in thousands, and in late 1958 the great invasion of the Silver Y moth (Plusia gamma, L.) truly rivalled those of the ladybirds and hover-flies. Had it been a more colourful insect, people would have been more alarmed, for one could see several hundred at a glance in gardens and on roadsides, all showing their characteristic " perpetual motion ". Being grey and black and harmless, they caused little concern. (I found them as plentiful then in Devon as in Suffolk.)

A contrast to the Silver Y is the Clouded Yellow butterfly (Colias croceus, Fourcroy), always noticed, even when seen singly, because of lts brilliant yellow colour, and its fame as a migrating insect.

In Sussex I saw it truly abundant in September, 1947, but in Suffolk it is never really common. In 1964, I have seen only two, one on the sea wall at Slaughden on 16th August and one on the railway embankment at Haiesworth on 29th September.

Red Admirals (Vanessa atalanta, L.) have been plentiful in 1964, and at least one started its life locally. I noticed it as a fĂźll grown caterpillar on 26th June, busily joining the edges of a Haiesworth nettle leaf, in order to make itself a shelter. Instead, 1 lent it my bungalow, and it pupated on 2nd Julv. I was able to release the butterfly on the 16th.

Painted Ladies (V. cardui, L.) were scarcer. I was told of one seen on 14th May and I took anotherat Aldeburghon 16th August.

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Transactions of the Suffolk Naturalists',

Vol. 13, Part 7

All these Lepidoptera are known migrants. Other kinds, having not known migrant habits, may also increase in evidence. They may have found food plentiful, the weather kind, or have come as tourists—we cannot be sure. Insects are difficult to mark, too numerous to check, and too short-lived to hope for recovery, so nobody can do more than guess the origin of any population rise.

I have missed the Burnished Brass moth (Plusia chrysitis, L.) since 1946 yet in 1964, I chanced upon it four times.

It is a close relative of the migrant Silver Y. Where did all those crane flies (Tipulidae) come from in midSeptember, 1961, when hundreds of " daddy long-legs " came through every lighted window ? I doubt migration here. Their " leather-jacket " grubs must have done extra well, but why in that year in particular ?

Why were Suffolk hedges plagued with webs of the caterpillars of species of Hyponomeuta moths in June, 1964 ? I removed many from my apple trees, I saw a Felixstowe hedge grey from end to end with the dirty drapings and droppings of these ravenous vegetarians, and a Westhall hedge actually got on to the Television.

Insects are not the only forms of life to swarm suddenly. One of our oddest cases was that of the orange-striped millipedes (Schizophylium sabulosum) who suddenly decided to leave Thorpeness beach on 25th May, 1963, and climb in their thousands to the eaves of a local resident's house, to his great consternation. I eould not explain to him what had " sent them up the wall", but a similar migration was seen on sand dunes at Holkham in Norfolk, so the cause lay outside Thorpeness.

Mammals are not so spectacular, our best example would be the rise and fall of the coypu, but in this case at least, the causes are well understood, and the effect less sudden.

Plants pose a different problem, due, apparently, to seeds waiting many years to germinate. Two weeds appear in numbers after road-widening Operations, the Poppy (Papaver rhoeas) and the Com Marigold (Chrysanthemum segetum). Poppies are common enough weeds, but the Com Marigold has not been a problem in Suffolk for very many years (though I noticed it to be a common weed in the Isle of Skye in 1957). Both these flowers made a particularly fine show of red contrasting with brilliant yellow when the narrow road south of Common Farm, Leiston, was widened along its whole 950 yard east bank, to admit lorries to Sizewell. Those Leiston seeds must have been extremely old.

I have tried to show here how a naturalist is not merely interested in " rare species ", but can get as much excitement from one which has become over-abundant. Yet I must admit that I would dearly love to experience " another 1872 " when at least forty-five of the rare Camberwell Beauty butterflies (Nymphalis antiopa, L.) were reported in our own county.