Photo Blog

I love observing nature through the changing seasons both in my Norfolk wildlife garden and the surrounding countryside. I blog about wildlife gardening as well as about Norfolk butterflies, wildflowers and other flora and fauna that I come across. Bookmark my Norfolk nature photo blog to keep up to date with my photographic adventures.

An Aberration!

A Small Tortoiseshell aberration semiichnusoides butterfly showing merged costal black spots and white marginal streaks instead of blue studs on the forewing and missing the orange band on the hindwings

Our hot late June summer weather didnt last too long, and perhaps could be deemed an aberration in its own right, but it also seems to have had a major impact on our caterpillars while they metamorphosed into butterflies.

I got curious when I spotted this unusually marked Small Tortoiseshell butterfly and discovered a strange world of genetics and temperature driven body chemistry!

It takes about 4 weeks for a caterpillar to metamorphose into an adult butterfly in a fascinating “black box” process that science still knows surprisingly little about.

The term for a butterfly with these atypical variations in markings is “an aberration”, which stems from the latin aberrationem, literally meaning “a wandering”. First used in the 1590s, the modern meaning of “a deviation from the normal type” is attested by 1735.

It turns out that both genetics and abnormal weather (and perhaps even the two in combination) can play a role in triggering these deviations. Aberrations are caused when something interrupts the usual pattern of markings during their development inside the butterfly’s chrysalis. One hypothesis is that sudden temperature “shocks” (in either direction) may trigger melanin release (a dark pigment) to increase or decrease.

Another possibility is the activation of rare inherited “recessive” DNA genes (a gene that requires both parents to have it to be activated) that are atypical because they hinder the chances of an individual finding a mate, or even surviving under normal conditions. They continue however to be carried in the population because they may perhaps aid survival in abnormal conditions.

One example of this is the better known aberration - the dark brown“Valezina” form of the Silver-washed fritillary quite often seen now at Holt at Foxley Woods. Valezina, due to its dark colouration is more able to fly and find nectar in unusually cool temperatures than its typical bright orange counterpart, but which may then be at a disadvantage when it comes to finding a mate and reproducing due to being less readily recognised.

Whether the sudden temperature change we saw at the end of June activated a dormant gene relating to surviving with abnormal weather or coincidentally acted directly on melanin production remains one of the fascinating mysteries of nature.

Small Tortoiseshell Aglais urticae (normal type) vs Small Tortoiseshell (aberration semiichnusoides). Both butterflies are likely to be siblings as they were hosted as caterpillars on my nettle bed and appeared fresh on the same day together.

Resources and References

“Variation in British Butterflies” by Peter Eeles, Dispar magazine

British Butterfly Aberrations - Reference Website

Grow Garlic Mustard for Butterflies

Many gardeners don't realise that Garlic Mustard, alliaria petiolata, is an important host plant for both Orange-tip and Green-veined White butterflies so innocently pull it up right as the butterflies are laying on it. This is a tragedy for the butterflies, but also a shame because Hedge Garlic, as its also called, is an attractive wildflower in its own right with beautifully scalloped fresh lime-coloured leaves, dainty white jasmine-like flowers and can look wonderful against a south facing wall.

May proved an eventful month, and not exactly for the best of reasons…

Orange-tip butterfly ovipositing on Hedge Garlic / Garlic Mustard, *Alliaria petiolata*, in my wildlife garden

One wildlife gardening project that I've been working on for a long time, in fact more or less since I moved in almost ten years ago, was how to get Orange-tip butterflies, Anthocharis cardamines, to breed in my wildlife garden. At first I planted Cuckoo flower, Cardamine Pratensis, the Orange-tip's best known primary host plant and the one they are always associated with. It tried it in my then new bog garden and by my pond margins, but the site proved too sunny and dry and Cuckoo flower failed to establish there.

Then I learned a less well known fact: Orange-tips also have a second primary plant, Hedge Garlic, Alliaria petiolata, also known as Garlic Mustard or Jack-by-the-hedge. This is a very different plant, larger, with beautifully scalloped lime green leaves, small Jasmine-like leaves, and it's even edible. It's a wanderer of part-shaded leafy lanes and hedgerows and is often used by butterflies as a more abundant alternative. Now that sounded alot more promising.

But for some reason I still struggled. Hedge Garlic is a biennial that behaves much like a foxglove. At first the Hedge Garlic didn't return, so I tried a variety of positions, all seemingly unsuccessful. Then I had an unexpected breakthrough, a self seeded patch popped up in, of all places, my gravel trap, not in part shade as everywhere advises, but southfacing and in full direct sun, exactly where the butterflies need it to be to lay on it. It seemed super happy there with damp feet and poor soil and went from strength to strength.

Finally, another three years on, I had a large clump running across the whole wall in a sunny position. Then this year Eureka! I spotted a female Orange-tip honing in on the patch, checking the flower tips out for prior eggs and then ovipositing some eggs in the bracts of several flower tips. I even managed a grab shot with my camera. I was euphoric and simply over the moon, I'd finally cracked it!

Two days later I took my camera out onto the patio preparing to photograph the eggs looked up and shrieked in horror. The gardener had been that morning, taken some initiative and “tidied” the whole wall! It turns out that not many people know that Hedge Garlic is a Orange-tip host plant.

Devastated, I spent the evening rummaging through the compost bin. Remarkably I saved about a dozen eggs and even more incredibly all bar one of those hatched. Despite various challenges rearing such minuscule hatchling, a few caterpillars were successfully released back into the wild on replacement host plants.

How Gardeners can Help Orange-tip Butterflies

Gardeners can help Orange-tip butterflies in three ways: Firstly by allowing self sown wild Hedge Garlic to grow in their garden, secondly by checking any Garlic Mustard they do need to weed out for butterfly eggs and relocating either the plants or the actual stems with eggs to a safe alternative host plant and lastly by proactively growing a patch of Hedge Garlic in a suitable sunny spot .

How to Transfer Orange-tip Eggs when Weeding Garlic Mustard

Orange-tip butterflies are most likely to have laid their egs on plants in a predominantly sunny aspect. If you do need to weed out a patch of Garlic Mustard then first check the undersides of the flower buds and bracts for eggs. The eggs are usually proud and bright orange so although small tend to be quite visible. If you find any, either pot up the plant, move it to a convenient spot and look after it. Otherwise clip the section with the egg on and then tie it high, as close to the flower tip bracts as possible onto another plant stem that is without an egg and that will be left in situ (or if wild, definitely won't be strimmed in road verge management). Tie the section securely, but without damaging the host plant stem, using fine wire or a non-fibre-shedding thread, if possible leave a route for the caterpillar to migrate avoiding contact with the tie altogether. The caterpillars are so miniscule on hatching they can even get caught in microfibres from polycotton just as in a fine spider web.

Lastly, its important to only put one egg onto each plant, or at least each flowering stem if the plant is a very large second year one. This is because the Orange-tip caterpillars are opportunistic cannibals and will eat each other if they cross paths.

Growing Garlic Mustard as a Butterfly Host Plant

Growing Garlic Mustard can actually help two spring butterfly species, as it is also the caterpillar host plant for another attractive white spring butterfly, the Green-veined White. The caterpillars however are not in competition with each other as the Green-veined White caterpillars eat the leaves of the plant whereas the Orange-tips feed on the seed pods.

Garlic Mustard is very easy to grow from seed in autumn or you can buy young plants from online wildflower providers like Naturescape in spring. Other native plant suppliers are available, do order youor Hedge Garlic early to catch egg laying season.

You will need to grow a generous clump in a sunny area (The butterflies don't generally oviposit on plants in shade) and grow them somewhere you can leave the plants all year even after they die back as many, though not all, caterpillars stay and pupate on the plants. Keep an eye out for ovipositing females and then look for the orange eggs regularly. Eggs are pale yellow day 1, turn bright orange on day 2 then fade to dull brown a day or two before hatching after about 7 days.

If you have grown Garlic Mustard in pots then you can optionally check over the flower heads and buds for predators, (moneyspiders with fine webs, aphids and ladybird larvae were all lurking in wait for mine) evict the predators and transfer the pots into a netted butterfly habitat to reduce predation. At time of writing 90cm butterfly habitats can be ordered online for about £15 from places like Bugzarre.

You can also grow Cuckoo flower, the Orange-tip butterflies’ other primary host plant, if you have a pond margin or bog garden of course. Orange-tips will occasionally lay on other crucifer wildflowers such as Charlock as well as Dames Violet and Honesty but larval survival is generally considered poor on these latter plants.

Hedge Garlic against a powder blue background — Garlic Mustard or Hedge Garlic is an attractive wildflower in its own right and deserves a place in every wildlife garden

Female Orange-tip butterfly nectaring on Hedge Garlic, *Alliaria petiolata*, flowers

Orange Orange-tip butterfly egg — Day 2 Orange-tip butterfly egg

Orange tip caterpillar- 1st instar or moult — Orange-tip caterpillar - 1st Instar or Moult

orange-tip caterpillar 2nd instar or moult — Orange-tip caterpillar - 2nd Instar or Moult

Orange-tip caterpillar - 3rd Instar or Moult — Orange-tip caterpillar 3rd Instar or Moult

A Painted Lady Summer

Painted Lady, Vanessa cardui nectaring on white Buddleia. Will 2019 be a record-breaking Painted Lady summer?

As the Butterfly Conservation Society’s annual three week long Big Butterfly Count draws to a close, the UK looks set to have enjoyed the magical, once-in-a-decade phenomenon called a “Painted Lady summer” when the apricot- and black-marked species arrives here en masse.

The last such event occured in 2009, when some 11 million Painted Ladies, known as Vanessa cardui, arrived on our shores and there is speculation that 2019 could be a record-breaking year.

But how is it that a butterfly that doesn’t survive our winters and isn’t even permanently resident in the UK manages to congregate here in such numbers?

The Painted Lady, a member of the large and colourful Nymphalidae butterfly family, is a poweful flyer and long distance migrant. During its migration it can achieve an impressive speed of almost 30 miles per hour and fly some 100 miles in a day. In fact, it’s 7,500 mile round trip migration from North Africa as far north as the arctic circle is even longer than that of the famous Monarch butterfly, which travels up and down the North American seabord.

Freshly emerged, second generation Painted Lady nectaring on a budding Common Knapweed flower

Despite its flying prowess, like the Monarch butterfly, Vanessa cardui traverses its intercontinental route multigenerationally and, having only a 2 week long life span, takes about 6 generations to complete it.

Each season the butterfly flies northwards from the desert fringes of North Africa to reach mainland Europe and then on to the UK, reaching Britain in late March. Here the newly arrived lepidopteran immigrant lays eggs on Marsh and other Thistles, Viper’s Bugloss, Mallow and Nettles. After about a month-and-a-half later the next generation emerges (46 days according to devoted turn of the century lepidopterist F. W. Frohawk).

These native-born Painted Ladies then lay a brood of their own, which, further supplemented by arrivals from both Europe and Scandinavia, significantily boosts numbers towards late summer. Some of these butterflies will commence the return migration southwards as the seasonal conditions turn.

So what makes the once in a decade “Painted Lady year” of mass abundance occur? Experts believe that the butterfly’s migratory instinct may be triggered by population density (leading to competition for egglaying sites and food sources) and in exceptional years, unusually good food availability and favourable weather conditions foster population booms. This in turn triggers mass North- and Easterly-bound migrations, often with hundreds, even thousands of butterflies reaching landfall along the UK’s East and South coastline, some arriving from Europe, others from Scandinavia and some even directly from Africa in favourable windstreams.

As well as Thistles for egg laying, depending on its generation, adult Painted Lady butterflies will nectar on a wide range of plants. These include Knapweeds, Buddleia, Trefoils, Hawkweeds, Heather, Privet, Ivy, Bugle and Clovers, so planting these species, and tolerating that annoying thistle or two (you can always deadhead later to stop the patch growing!) increases the likelihood of you attracting this orgeous, intricately-marked butterfly into your garden and enjoying your very own Painted Lady Summer.

Painted Lady nectaring on White Buddliea head on.jpg

Sources:

A Purple Streak

The colour purple became my leitmotiv during early July. It is the season of the purple butterflies and therein lies a tale of mystery and obsession...

The Oak tree canopy is a habitat for both Purple Emperor and Purple Hairstreak butterflies, which both feed on aphid honeydew

Two very different, yet equally enigmatic, purple butterfly species are on the wing towards the end of June into mid-July. Though very different in fame and stature, both share two things in common: a fondness for the heady heights of mature Oak tree canopies in deciduous woodland and a strong reputation for elusiveness and ability to evade the gaze of even the most determined of butterfly seekers.

Since being drawn into the world of butterflying I've discovered that, since time immemorial, avid butterfly chasers have gone temporarily a little doolally at this time of year. The hysteria is all over a certain famous, purple-cloaked member of the royal family who is not, officially at any rate, currently resident in Norfolk - the magnificent Purple Emperor.

Known affectionately to his acolytes as "his Majesty" or sometimes simply "Iris", the Purple Emperor is neither Britain's largest butterfly (our very own Norfolk Swallowtail), nor the rarest (the once extinct, recently reintroduced Large Blue), nor even the brightest (arguably the Silver-washed Fritillary) so this seemingly bizarre Purple Emperor obsession had been puzzling me for some time. Just what quality is it that bewitches them all? Is it the dramatic colour purple? Their reputed vigorous flight and aggressive behaviour? Or some other mysterious factor altogether ....?

After an inspiring talk by renowned butterfly conservationist and Purple Emperor advocate Matthew Oates at Norfolk Butterfly Conservation's AGM back in 2016, I became intrigued and not a little bewitched myself. In a bid to sate my curiosity and discover the obscure reason for the Purple Emperor's celebrity status for myself, I started planning a field trip to visit his Imperial Majesty's haunts, mature Oak and Sallow woodland rides.

Alas fate was not on my side, despite attempts to make visits to Fermyn Woods in Northants, Wood Walton Fen in Cambridgeshire or Theberton in Suffolk, life events have intervened and scuppered my plans well and truly for this year. Perhaps Iris is to be my new five year nemesis butterfly, who knows.

With my ability to range much curtailed, I was crestfallen and deeply disappointed. But there was still the second less famous, but to me equally elusive, purple butterfly to discover: the Purple Hairstreak butterfly, Neozephyrus quercus. And it lives much closer to home.

Although much smaller, the Purple Hairstreak butterfly shares a surprising number of characteristics in common with its larger Imperial cousin. As suggested by its Latin species name "quercus" it too favours mature deciduous oak woodland and so is also highly elusive (and under-reported) as a result to its habit of dwelling up high amongst the tree canopy. There it lives on honeydew produced by aphids and only rarely descends from the "throne" for the odd sip of bramble nectar.

A Purple Hairstreak butterfly perched on an Oak tree leaf near the edge of Syderstone Common, Norfolk

While laid up I did my research thoroughly. Purple Hairstreaks being far more widespread than his majesty, I was able to find some promising local locations in Norfolk, and had in fact already experienced my first brief glimpse of a old faded and tattered Purple Hairstreak on a dog walk at Holkham Hall one August a few years back. I took a punt on a very short run up to the nearby Syderstone Common nature reserve, on the edge of North Norfolk coastal AONB. Its a large reserve of lowland gorse heathland, an SSSI that is famous for its Natterjack toad population, but not all that much else, in fact a previous visit had left me visually underwhelmed. This time however the reserve was transmuted into a spectacular sea of vivid fuchsia pink willowherb flowers swaying in the gentle breeze.

Essex Skipper butterfly perched on a Rosebay Willowherb flower spike

My fieldcraft skills must have improved somewhat as I was delighted to spot an active Purple Hairstreak quite soon into my visit. There it was, a small grey blob fluttering away right up high in the treetops, initially silhouetted against the cloudy sky. Its flight was erratic and it was hard to keep track as the butterfly flitted amongst the oak treetop and nearby birches in the mature woodland circling this now spectactularly beautiful reserve.

After spotting my Hairstreak's "Master" Oak I stayed for some time, craning my neck to try to spot this diminutive butterfly amongst the oak leaves. Eventually one dropped a little lower and permitted a quick shot before circling up high again in a cluster of nearby Birches.

On my way back to the car I spotted a beautiful young buck Roe Deer, who paused, checked me out for a little while then barked at me before trotting off back into the Oak woodland, a beautiful end to my successful visit. Although my sightings had been distant and tantalising, I had bagged my first purple.

Perhaps the abiding memory for me is not so much finally photographing my first purple butterfly, but rather Syderstone Common nature reserve itself, which was a natural habitat at the peak of its mid-summer glory and afforded a sensory firework display of wildflower delight at every turn.

Visually the abundant vibrant pink Rosebay Willowherb flower spires intermingled with creeping carpets of rich yellow Tormentil, while the heady scent of rambling native Honeysuckle hung in the air and bramble in full bloom. Every plant seemed to be alive, swaying in the breeze and dancing with a host of orange Skipper, Ringlet and Meadow Brown butterflies flitting about into the distance as far as the eye could see.

As for purple Royalty... I must now be patient, wait and bide my time till 2018 brings a whole new season and fresh opportunity for his Imperial Highness to ensnare me as subject.

We shall see...

Vivid pink Rosebay Willowherb can be spectactular when in full bloom

A young Roe Deer buck on Syderstone Common, Norfolk