All posts by Chris Gibson

Return to Gunnersbury Triangle: wasp galls on an oak tree

A couple of years after our first, delightful visit to Gunnersbury Triangle (see here), we were again in the vicinity last week, and took the opportunity of a perfect, mellow, sunny autumn day to sample its delights once more. In practice, we spent most of our hour there staring at just one tree, a three-metre Pedunculate Oak on the edge of a clearing, simply laden with galls…

Oak is of course renowned for the number of insects it supports. Many of those cause the formation of galls, abnormal growths in the host plant triggered by its interaction with a gall-causer. While many gall-causers are tiny (and essentially identical without microscopic examination), different species can be told apart by the shape, colour and texture of the galls in which their larvae develop. Those caused by Gall-wasps (Cynipdae) are some of the most distinctive, and all those shown below fall within that group.

Galls can form on any part of the tree, but most obvious are those formed on buds and acorns, and those on leaves, often on the undersides. Perhaps surprisingly given its abundance in recent years, ‘our’ tree had no signs of the large, sticky, woody acorn distortions (Knopper Galls) of Andricus quercuscalicis, but other bud/acorn galls were obvious. By now we are reasonably familiar in Essex with both Ram’s-horn (Andricus aries) and Cola-nut (Andricus lignicolus) Galls, the latter like small, rough, scaly versions of the Marble Gall (Andricus kollari), one of the commonest species everywhere but again apparently missing on this tree. All four of these are relative newcomers to this country (Marble 1830s, Knopper 1960s, Cola-nut 1970s, Ram’s-horn 1997) and have now spread more-or-less widely.

But especially exciting for us was one we hadn’t seen before, the Hedgehog Gall of Andricus lucidus, dramatic pompoms of blobby-ended spokes. Another newcomer, this was first found in Britain in London in the 1990s, but has hitherto shown few signs of spreading far.

London is seemingly the initial focus for many of these new arrivals, presumably in part due to the heat-island effect of the city, keeping winter temperatures 5°C or more higher than in the countryside, and favouring these species originating from more southerly climes. Another contributing factor could be the relative abundance of Turkey Oak alongside native Pedunculate Oak in London’s woodlands. This tree also originates from southern Europe (although the fossil record shows it to have been native here before the last Ice Age), and interestingly all the galls mentioned above (except possibly Ram’s-horn) rely on both oak species for specific stages of their life-cycle. With two generations a year, the sexual generation requires (and forms galls upon) Turkey Oak, while the asexual, late-summer generation is the one we were looking at…

Ands so to leaf galls. There are three widespread and familiar Spangle-galls, the Common Spangle Neuroterus quercusbaccarum, the Silk-button Neuroterus numismalis, and the Smooth Spangle Neuroterus albipes.

All were present on our tree, with Smooth Spangle typically the most scarce. But most certainly not present and correct, because most of the Smooth Spangles, instead of being flattened, smooth, whitish or pink discs, were puckered into the most beautiful flower-like forms.

Another new one for us! But what was it? Eventually, we came up with a name from the internet. Neuroterus albipes variety reflexus. Or perhaps Neuroterus albipes subspecies reflexus. Or just perhaps even a separate, as yet undescribed species, ‘Neuroterus reflexus’. It seems nobody really knows what it is, or even where it is: the normally reliable Fauna Europaea database shows it (as ssp. reflexus) scattered across Europe, but perhaps significantly NOT in Britain or Ireland, nor indeed France, Germany and the Low Countries.

From our observations, we could well believe it is something different to albipes altogether, both from its distinctive, consistently variable shape, but also giving the strong impression of being more strongly associated with the main leaf veins than true albipes.

But there are perhaps other possibilities too. A reflexus gall on one leaf was being closely attended by a tiny 3mm wasp. Completely the wrong time of year and indeed the wrong shape for one of the gall wasps, this looked more like a parasitic species with a long ovipositor. Could the ‘reflexus‘ galls simply be parasitized Smooth Spangles? After all, big fleas have little fleas upon their backs to bite ’em, and little fleas have lesser fleas, and so ad infinitum….

Whatever the truth, a delightful hour of Gunnersbury Triangle magic provided us with new and interesting sightings, and more questions than answers!

#WildWivenhoe Botany & Bug Walks: October – Cockaynes Wood

It has been said that ‘Words are easy, like the wind’, but some words we learned on our walk today were not particularly easy, in fact decidedly complex!  Pangaea and Gondwanaland two for starters, not to mention Samara and Parthenogenesis….

The first two cropped up in relation to two beech trees, the European Beech and Southern Beech which stand at the edge of the track down to Cockaynes Wood, the destination of our Botany and Bug walks this month.

These two distantly related species, albeit in different families, share a common ancestor which occurred many millions of years ago on Pangaea, a supercontinent that included all the landmasses of the Earth. That subsequently broke up into Gondwanaland (present day South America, Africa, Arabia, Madagascar, India, Australia, and Antarctica) and Laurasia (everywhere else).  When the separation occurred, the common ancestor went with each landmass, but different climates and natural selection pressures drove the evolution of two now-separate families. It was recognition of such relationships which gave some of the most convincing evidence for the new theory of continental drift, as recently as the early part of the 20th Century.

Our main focus this month was the trees and fungi of the wood, and some of the creatures therein.  Whilst fungi were not particularly plentiful, we found some of interest including a ‘troop’ (yes, it is the collective noun) of Puffballs forming a fairy ring, a Deceiver, Birch Bracket, plus our old favourite the Fly Agaric.  This familiar red and white toadstool grows associated with Birch, and although there are many of these trees in the wood ( so plentiful in fact that they need to be managed to keep them under control, particularly in the open heathland areas), we only found one small patch to admire.  Fly Agaric is renowned for its hallucinogenic properties, and being plentiful in Lapland has been associated with flying reindeer, and the whole red-and-white Santa Claus phenomenon.

A Witch’s broom, often mistaken for a bird’s nest, is often also caused by a fungus, in this case the fungus Taphrina betulina on Silver Birch, one of several microfungi we encountered. Others included the powdery mildew Microsphaera alphitoides on Oak leaves and the rust fungus Phragmidium violaceum, red splodges on the upperside of Bramble leaves, and erupting volcanoes of black spores below.

A few invertebrates were also on show.  A suite of our favourite bugs – Squash, Green Shield and Forest;  a splendid Devil’s Coach Horse beetle which adopted its fiercest pose; Pine Ladybirds; plus a pristine Painted Lady basking in the weak morning sun.  It is hard to believe that these fragile-looking creatures are migratory and able to fly thousands of miles.  Those on the afternoon walk missed the adult, but an eagle-eyed member of the group spotted the caterpillar, itself an amazing beastie.

Spiders and harvestmen (arachnids, not insects, due to not having the requisite six legs) were out in force ready to catch careless flies for lunch.  Some, like the familiar Garden Spider, produce sticky webs to effect this whilst others rely on stealth.  It was also a privilege to see the very active Hornet’s nest in a hollow tree.  These huge, beautiful creatures are much maligned, but if left alone are not aggressive or harmful, and they do much good in gardens and woodlands, helping to control the legions of aphids and other ‘pests’.

And so to another of our words of the day, ‘parthenogenesis’, meaning asexual reproduction.  The wonderfully named Virgin Bagworm, living on assorted fence posts, indeed lives a pure lifestyle.  These weeny wingless moths produce tiny bags which they decorate with lichen, and in which they (all females, no boys allowed, in fact they don’t exist) live for their whole life.  They can produce babies all by themselves with no help from anyone.  Hope it doesn’t catch on!

As for the trees in the wood itself, Sweet Chestnuts were plentiful, in places their leaves sculpted by the excisions of leaf-cutter bees, along with Holly, English Oak and Silver Birch. Hornbeams were at the fruiting stage, producing masses of dangling papery bunches, bunches of winged seeds or ‘samaras’, the last in our lexicon of odd words.

We finished the day with a flourish, seeing a Common Lizard basking in the glorious afternoon sunshine, an amazing aggregation of Scatopsid flies (aka Black Scavenger Flies), plus a veritable collection of Odonata  (dragonflies to you and me) hanging around, catching the last rays of the day: a Migrant Hawker, a few Common Darters, and  several Willow Emerald damselflies, a recent colonist of the British Isles, assumed to be one of the (rather few) upsides of Man-induced climate change, better thought of as climate breakdown, catastrophe even.

As always, many thanks to you all, old friends and new, that joined us .

The Beth Chatto Gardens throughout the Seasons: September

Summer returning with a flourish, sun streaming from a cobalt sky, but the signs are there… autumn is upon us, the leaves are turning. And also falling, seemingly on the early side, perhaps one result of a droughty August.

Before the fiery flames of high autumn sweep through Nature’s realm, delicate pastel shades  are more to the fore…

…with colour-bursts and blasts to remind us of the summer now departed.

A lower sun extracts hues, textures and patterns from the garden that may otherwise be missed.

Still plenty of nectar and pollen sources around…

…and insects to take advantage.

Others basking wherever they can, to warm up enough for the the final act, their legacy, producing the next generation. It was especially good to see several shrubs festooned with the metallic green matchsticks that are Willow Emerald damselflies, only recently established in Britain, but now a reliable feature of early autumn here.


In the wider countryside, Ivy is the final main course of the season, its flowers vats of nectar and pollen, enveloped in a heady, sensual, musky poll of scent, and the persistent hum of a myriad of visiting wings. Even with blowsy blossoms as a distraction, the allure of Ivy which has decided to make the garden its home still pulls them in.

Down at the ponds, Thalia, that (not very ) beautiful assassin (see last month’s blog), is still exerting its fatal attraction.

Spiders too are taking their toll on the insects, but at least they – unlike Thalia – eat their victims.

And it was particularly exciting to be shown a Wasp Spider which has taken up residence in the Dry Garden, feasting on the local grasshoppers. While not uncommon in rough grassland right by the estuary, this is the first time we have seen it in the Beth Chatto Garden, a space for plants and all that they encourage.


Standing up for Phyllis Currie Reserve – September

Our fourth and final planned visit of the summer to Phyllis Currie was sadly blighted a little once again by uncertain weather: cool, dull and breezy, not the long days of insectivity we had been hoping for at the outset. Nonetheless, examination of the various leaf-mines and galls helped to swell the number of species we recorded  – feeding signs are just as valuable a biological record as seeing the critters themselves!

And searching among the foliage did of course reveal some invertebrates, especially arachnids and flies, along with numerous Box Bugs at every stage of development from egg to adult.

Even if the weather had been suitable, our usual method of looking for nectar and pollen resources would no longer have been especially productive. In contrast to the flowery swathes of past visits, it was down to Water Mint by the ponds, and Wild Carrot in the meadows. Just Ivy to come and it will be time to buckle up for winter.

But as the photos show, some of the most noticeable changes at the reserve since our last visit were the developing fruitfulness of the shrubs and trees…

…and the general shift from summer greens to autumnal hues, a tendency to russet in both the leaves and the insects.


So what of our summer’s explorations? What we haven’t done is found anything so rare that it would be a showstopper for the adjacent development. But then again we never expected to. We have added a whole raft of species to the reserve list, which are evidence – evidence of wildlife value – which will hopefully play a part in the local actions to protect and enhance Phyllis Currie into the future. And it gave us the impetus to seek out and explore this hidden gem of Essex, well off our usual beaten paths: it is a delight to know such places are still there for all to enjoy.

Our previous blogs are linked here:  April  June   August

#WildWivenhoe Botany & Bug walks: September – Ferry Marsh, after The Flood


Ferry Marsh is part of the Colne Local Nature Reserve, owned and managed by Colchester Borough Council, and this was our destination for September. In days of yore, part of this area was a grazing marsh, but more recently, since the housing development on West Quay, it has been set aside for nature conservation purposes. Rainwater falling on the roofs of the new properties is directed onto the marsh;  this, together with springs and tributary streams, keeps it damp and the channels full of water for their famous occupants, the Water Voles. The idea is that the sluice into the River Colne allows excess water to drain out at low tide, but as locals know this system has been prone to go awry and for the past couple of years the whole marsh has become more or less permanently flooded. How did this affect the wildlife? Well this is the question we were interested in.

Although the weather forecast had been good, hey ho, the wind and the rain plagued us in the morning session, with a resultant meagre selection of insects. The sunshine in the afternoon warmed up some additional species, including both Ruddy and Common Darter dragonflies, two colour-forms of the tiny Slender Groundhopper and a picture-winged fly Ceroxys urticae.

But the morning session was not without its entomological interest, and we were treated to four butterfly species, including a splendid fresh-out-of-the-pupa Red Admiral, as well as Green-veined White, Small White and Painted Lady, plus some wonderfully-named Long-winged Coneheads and a stunning Roesel’s Bush-cricket.

Having been totally inundated for some considerable time, most of what is currently supported by the marsh has only been present since the water-level subsided. This is obviously true for most of the plants, but also for creatures such as the Green Shield-bug, which we saw in various stages of development. An adult earlier this year would have flown in and laid eggs on a suitable food plant. The subsequent baby bugs ( known as instars), unable to fly, gradually munched their way through the relevant herbage, shedding their skins up to five times, until they reach adulthood and only then acquired wings, and, as Chris would say, ‘ naughty bits’.

Talking of sayings, you may know the phrase ‘Sedges have edges and Rushes are round ‘. This was demonstrated to be true whilst examining the plant life. Confusion is only just round the corner, though, as the Club-rush is actually a sedge, whilst what we think of as a Bulrush, is not a rush at all, nor a Reed, but a Reedmace. The joy of our inaccurate English names!

Whilst the beautiful Common Reed takes pride of place, both visually and aurally, at present, we also discussed some of the many other plants which have colonised, including  Gipsywort and several species of yellow ‘composites’ like Prickly Ox-tongue, Prickly Lettuce, Fleabane and Sow-thistle (some of which were covered in this glorious purple blister-gall, caused by a gall-midge Cystiphora sonchi).

A surprising find was a single plant of the rare Jersey Cudweed, in a very different habitat to the cracks in the paving slabs on West Quay which it colonised five or so years ago. As we saw at the end of the walks, it flourishes there and seems not to be met with a barrage of glyphosate – do go and admire it if you haven’t already.

Unfortunately, no one spotted a Water Vole, though we understand they are doing well, and were able to survive the flooding due to the foresight of Darren Tansley and those who constructed the water channels and built a high bank in between them, which provided a refuge. The Spotting Award this month must go to one of our afternoon group, who incredibly saw a Common Lizard basking in the sun, not on the ground as you might expect, but nestled a metre or so up in a hedge!

As always, thanks to you all who joined us.

Our new toy – a compact portable moth trap

Living in a top floor flat has many advantages – the light, the views, the health benefits of 53 stairs to climb – but it isn’t really compatible with regular moth-trapping. Lack of space means our large Robinson trap is now relegated to the loft space, emerging only on special occasions, and those are restricted to times when we have access to mains electricity or a generator.

A chance meeting in Cambridge Botanic Garden alerted us to new style, truly portable LED traps now available from our friends at Anglian Lepidopterist Supplies. Run off a rechargeable small battery pack, LEDs have been sourced which emit strongly in the UV light spectrum, the frequencies which many moths respond strongly to. This helped overcome our scepticism about LED traps, and we decided to invest.

The trap has now had four outings, so time for a review. Our expectations were managed at the outset with the suggestion it was likely to be most effective in very dark conditions, so we had no high hopes when we ran it in a friend’s urban garden with skyglow, only 10m away, but shaded from, his 125W MV trap light. It was good to see the light still on first thing – the battery had performed to expectations – but compared with the adjacent MV, fewer free-range moths outside the trap. However once inside, it was a very pleasant surprise to find a goodly proportion of the species from the big trap, including a Privet Hawk, three Elephant Hawks, Scarce Footmen, Least Carpets and Brown-tails,

Apart from the greater number, the only things in the big trap which turned us appropriately green with envy was a Green Silver-lines and an L-album Wainscot, and we had several species not in the big one, including Bright-line Brown-eye, Iron Prominent and Latticed Heath, together with the distinctive nose-down micro Pediasia aridella and a Sexton-beetle.

Second outing was close to the Wivenhoe Barrier, overlooking salt-marshes, a generally dark zone but again with distracting intrusion from security lights. Almost instantly the LEDs attracted hundreds of Water Veneers, a short-lived whitish micromoth which emerges in a coordinated way to maximise the chance of meeting and breeding.  Ruby Tiger, Yellow Shell, Diamond-back, Cloaked Minor and Dingy Footman also popped in, along with the mayfly Cloeon dipterum, several caddisflies, and from an entirely different habitat, a Nut Weevil.

Two nights’ later in the same locality, it was a rather different picture. A little cooler, a little breezier, a more lingering twilight, and no emergence of Water Veneers. But again a few moths came in the hour or so of dark we were there, mostly LBJ micros (many being Bryotropha species) with only one different macro, a Rosy Rustic.

Finally, a truly dark location, Wivenhoe Old Cemetery, an old Victorian graveyard which has grown up into woodland, where trapping sadly terminated a bit early because of rain. The attraction was instant, the diversity reasonable, including several Orange Swifts and Straw Underwings, together with micros such as Nephopterix angustella (still considered to be an Essex Red Data species, despite recent increases) and Mint Moth, and the usual variety of hangers’-on, including caddis-flies, Nut Weevils and damsel-bug nymphs.

In a nutshell, this LED trap will never supersede an MV trap for numbers (of individuals or species), but not everyone has the time to process five hundred or more moths in the morning. But with the phasing out of mercury, MV bulbs are on the way out. And the portability (and flatpack storage) of the LED trap means that is likely to be the future of mothing for us.