Brighton blues

With our changing climate, distributions and abundances of a wide range of invertebrates are ever-changing. In this regard, the headline butterfly event of the year was the record-breaking influx of long-tailed blues, reaching the British coast from their regular haunts of southern Europe. At the moment, in September, the offspring of the first wave of primary migrants are emerging from the broad-leaved everlasting-pea plants on which the females had laid their eggs in late August, allowing keen lepidopterists another chance to see this elusive species. However, I did not need this second chance – I was fortunate enough to lay eyes on some of this year’s earliest arrivals.

Walking up Whitehawk Hill on the late summer day of 29th August felt typical, 20 degrees yet with a fresh breeze blowing up from the Channel. However, what I was about to witness was an indication of our warming planet.

Upon reaching the top of the hill, I immediately saw two small butterflies spiralling frantically upwards against the expanse of Brighton in the background. I knew exactly what they were – territorial male long-tailed blues. These were small, dainty yet tireless butterflies, which had crossed the Channel and much of Western Europe to gambol between the community allotments and the scrubby border of the local nature reserve in the shade of the transmission tower.

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During brief interludes between the combat, these two males and a further individual occasionally paused on ground vegetation, allowing photo opportunities and examination of the species’ beautiful intricacies. The long-tailed blue is so-called on account of the two ‘tails’ which project backwards from the hindwing. These mimic the antennae of the butterfly, and coupled with the eye-spots on both the upper and lower surfaces, the tactic is to make predators attack this end of the insect, thinking it is the head. This protects the actual head from any damage from hungry insectivores.

The photo below shows one of the more worn-looking blues. There are chunks missing from the left hindwing where the eye-spot usually is, suggesting a predator mistakenly attacked the rear end of the butterfly, fooled by the fake antennae. This left only superficial damage to the butterfly.

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I did not expect finding these long-tailed blues to be quite so easy, and in the past it certainly wouldn’t have been. The first British record of this species was from Brighton all the way back in 1859 (leading to one of its earlier vernacular names being the Brighton argus), although in the succeeding 80 years it had only been sighted again 36 times. The number of sightings more than doubled between 1940 and 1988, with a large proportion of these being during an influx in 1945. However, it took until 2013 and 2015 before the long-tailed blue numbers really became significant, when relatively major immigrations took place into the southern counties. Already it is looking likely that the 2019 influx will surpass all previous influxes.

But why are these long-tailed blues making an effort to reach our shores? There are many other butterfly species which have similar distributions to the long-tailed blue in southern Europe, although they have made no attempt to colonise the UK. However, the long-tailed blue is not only found around the Mediterranean – one of the world’s most successful butterfly species, its distribution also stretches right down to Australia. For such a small lepidopteran, its flight is powerful and determined, showing no reluctance to cross seas and mountain ranges such as the Channel and the Pyrenees. Furthermore, the long-tailed blue is renowned for its ability to pass through its entire life-cycle incredibly quickly. Despite most primary migrants only appearing in the UK in late August, their offspring already started to emerge as adults in mid-September. This allows the long-tailed blue to gain a foothold on new lands with great speed, which gives this species a huge advantage in the face of increasing temperatures in the long-tailed blue’s ancestral homelands. Although the current year-round climate of the UK is too cold for the species to overwinter, it is quite possible that it won’t be long before it is resident in the UK and there will be more chances to admire this resolute butterfly.

 

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The Saxons are invading again

In July 1987, Dolichovespula saxonica, commonly known as the Saxon wasp, was first recorded in the UK at Juniper Hall in Surrey. In the 32 years that has since passed, the species has spread throughout south-eastern England, with scattered records further north to Yorkshire and a handful of sightings from Scotland. Eventually, at the end of July this year, I saw my first ever Saxon wasp, in the same county it was first seen. It is one of two social wasp species which have colonised the UK in modern times, along with Dolichovespula media, the median wasp, which was first found by Steven Falk in 1980 in Sussex.

Contrary to what many people might expect, there are several thousand wasp species in the UK, ranging from tiny parasitic wasps which barely reach 0.2mm in length to the docile hornet. Most of these wasps are solitary, and the social wasps comprise only about 1% of all the world’s wasp species. They’re mainly restricted to the subfamily Vespinae, which has around 11 members in the UK.

My recent sighting of the Saxon wasp came as quite a surprise to me. In the past few weeks I’ve been noticing more broad-leaved helleborines Epipactis helleborine (a species of orchid) than I usually do in my local area. They like to grow beside paths within woodland, perhaps due to the increased amount of light that reaches their leaves in comparison to the centre of the dense woodland. As a result, they are one of the most frequently encountered orchids in my region. However, despite their frequency, before I found my first Saxon wasp I had never observed any pollinators visiting these orchids.

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A spike of the broad-leaved helleborine on my neighbour’s verge

As you can see from the photo, their flowers are not particularly attractive colour-wise. Many other orchid species have evolved to mimic their pollinators, so that they are not drawn to the flowers by the promise of a meal but by the promise of a mate; as a bee, for example, attempts to mate with the flower of a bee orchid, pollination will take place. Moreover, the flowers emit a scent mimicking the pheromones emitted by the female bee, attracting the pollinating bees from far afield. This may sound clever, however reducing your number of pollinators to just one or a handful of species greatly restricts spread. Indeed, in southern England, the pollinator of the bee orchid is quite rare, and most of the time the bee orchid reproduces by self-pollination.

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The early spider-orchid, despite its name, has evolved to mimic the mining bee Andrena nigroaenea. I can’t personally see the similarity, but perhaps the bees can.

However, the broad-leaved helleborine does it slightly differently. Its primary pollinators are social wasps, such as the common wasp Vespa vulgaris (one’s standard picnic-botherer) as well as the Saxon wasp. Like many flowers it produces a nectar to entice the wasps in. However, once the wasps have arrived at the orchid flowers, they begin to become intoxicated by traces of opioids within the nectar. The narcotic-like qualities of the nectar cause the wasp to sleepily visit all of the flowers on the orchid multiple times, to ensure that all the pollinia from the flowers are transferred. I like to think that the opioids are also addictive to the wasps to encourage them to visit other broad-leaved helleborines, but I’m not sure whether this has been studied yet!

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A drugged Saxon wasp walking between helleborine flowers.

In the photo of the wasp above, it is quite easy to see a number of white objects on the face of the insect. These are the pollinia of the orchid, which stick to the face of the wasp after it has visited each flower trying to reach the nectar within. Each individual flower only has a few pollinia, which is the whole product of an anther. It is a coherent mass of pollen which is attached to the flower by a stipe (or stalk) and has a sticky disk on the other end which attaches to the face of the insect. Ideally, the insect then transfers these masses of pollinia to another plant, where the pollen in the pollinia will be transferred to the stigmata, completing pollination.

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The wasp reaching into a helleborine flower, looking for nectar. The pollinia can be seen just above the thorax of the wasp, attached to the roof of the flower, ready to attach to the wasp. 

It was fascinating to document this sighting, which was two firsts in one: my first Saxon wasp, and my first observation of pollinia in action. I’ll be keeping an eye on the helleborines this summer to see if any other wasps are enticed to the flowers by the sweet nectar and drugs!

I smell a rat

16th July, World Snake Day

The region of southern Ontario where I was lucky enough to be able to stay for a couple of weeks in the first half of July holds an important yet threatened population of the Gray Ratsnake, Pantherophis spiloides. While participating in the memorable BIOSPHERE Youth Environmental Leadership Expedition at the Queen’s University Biological Station (QUBS) on the shores of Lake Opinicon, the enthusiastic program leader Dr. Shelley Ball interrupted our dinner one evening with a Gray Ratsnake she had just hand-caught. Perhaps one of the few things I will stop dinner for!

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Gray Ratsnake being held by Shelley

Gray Ratsnakes are one of Canada’s largest snakes. They are the largest in terms of length, with adult able to reach over six feet from head to tail, but are pipped by Bullsnakes with regard to mass.

During the expedition at QUBS, we were treated to a short presentation by Matt and Meg who are working on how to prevent the decline of this sizeable snake. One of the leading causes of fatalities in this species is road collisions. The dark colouration of the ratsnakes means that they are often mistaken for the shadows of overhead branches on roads, and are therefore not noticed by motorists. Even when they are recognised as snakes drivers have a hard time avoiding them, as due to their length they can easily stretch across the entire width of the road.

On account of this, Matt and Meg are working on avoiding these snake RTAs by reducing the incidences of snakes crossing the road. They are helping to develop snake-proof fences which aim to guide the snakes to specially-built culverts which they can use to get to the other side of the road without risking being hit. Gray Ratsnakes are semi-arboreal and spend lots of their time in trees, so are adept climbers. The fences to be implemented, therefore, need to be resistant to climbing by these agile snakes. Creating fences that not even ratsnakes can ascend also prevents a wide variety of other wildlife such as turtles from being hit and allows them to utilise the culverts as well.

Gray Ratsnakes are remarkably docile and are rarely aggressive when handheld. When threatened they do possess the abilility to release the contents of the cloaca, musking the assailant with a foul smell. However, the related Northern Water Snake behaves in this manner with far greater regularity. It, like the Gray Ratsnake, is non-venomous, so has to make itself as unappealing to predators as possible, by releasing both musk and excrement. Despite the lack of venom, the bites are still painful and the saliva of the Northern Water Snake has an anticoagulant which causes the bite to bleed more freely. However, although it might sound threatening, the water snake is another fascinating reptile.

I had the good fortune of glimpsing a Northern Water Snake on one occasion at QUBS as it swam past the boathouse. As its name suggests, it is a very strong swimmer. It will take sleeping fish at night in shallow water and during the day it will hunt other prey such as crayfish and amphibians among vegetation at the water’s edge.

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Northern Water Snake snaking through the water at the QUBS boathouse

To finish off this post for World Snake Day, I’ll mention the third species of snake we encountered on our expedition at QUBS, which was also the most numerous. The Common Garter Snake is, as its name suggests, frequent, but also fairly skittish. As a result, they are difficult reptiles to photograph. However, nearing the end of the expedition we disturbed one from a pile of dead leaves near the library. It retreated to a stone wall, from which it poked its head out to survey the scene, giving a rare opportunity to photograph this species.

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A curious Common Garter Snake.

The Common Garter Snake, like all but one snake in Ontario, is another non-venomous species. Snakes are often misrepresented as being solely dangerous creatures. However, less than a fifth of the world’s snake species are considered a threat to human health, with very few venomous snakes being found in the more populated temperature regions of the world. Instead of being feared, snakes should be more appreciated for their incredible diversity and fascinating range of habits.

Apples on sticks

Yesterday the south-east group of the British Bryological Society visited the town of Wadhurst in the far east of Sussex, near Tunbridge Wells. A variety of habitats including streams, woodland, grassland and ditches led to an array of moss and liverwort species being recorded. All were new for the area as this was a place no bryologist had dared to tread before.

Highlights included my favourite liverwort, the large and fragrant Conocephalum conicum (Great Scented Liverwort), as well as non-bryophytes such as two new plant species for me – Orpine and Soft Shield Fern – and a new carabid in the form of Carabus monilis with its bronze lustre. However, apparently the best find of the day was one of mine. This was the apple-moss, Bartramia pomiformis.

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Bartramia pomiformis

This moss immediately struck me, growing on a sandy bank on the edge of a narrow lane. The patch was almost perfectly circular, a richer green than the surrounding winter vegetation. And it was easy to see how it got its name, from the rounded apple-like capsules.

These capsules, that many mosses have in some form or another, form the final stage in the life cycle of a moss. The capsules contain the spores. Like a fruit, the capsules darken with maturity, starting off green such as these but soon becoming dry and brown with age, at which point the spores will be released.

These spores, upon germination, will then grow into a protonema, which will develop into a sheet of felt-like rhizoids, from which the gametophore will arise. The gametophore will be the stage of a moss that many people will be familiar with. It is the typical plant-like form, with stems and leaves, resembling a flowering plant although without vascular structure. This means that mosses lack the transport systems that vascular plants use to transport water, nutrients and minerals to their cells through tubes such as the xylem and the phloem.

Mosses can be dioicous or monoicous. Dioicous mosses have the male and female reproductive organs on different individual gametophores, while monoicous mosses have both sex organs on the same plant. In both cases, the sperm from the male sex organ will be transported to the female sex organ by a drop of water, which is one reason why there is a higher density of moss species in wetter climates such as the Atlantic rainforests of western Scotland and Ireland.

Once fertilisation takes place, a sporophyte begins to emerge from the venter, where the embryo develops. Over a period of many months, a seta (stalk) will grow, on top of which a capsule will be produced. Eventually this will release spores, and the cycle will repeat itself.

When diving into the life cycles of many taxonomic groups, I am often amazed by the complexity behind what appear to be fairly simple organisms at a cursory glance.

The Glue Pistons

For a long time I’ve been wanting to be involved in a recording scheme. Yet I had not quite appreciated the amount of work that is involved in managing what is often a massive collection of records. Over the past few months I’ve been collating the records of springtails (Collembola) from Surrey, which has been a big challenge, even with springtails being one of the least recorded invertebrate groups in the country.

Springtails are often tiny arthropods with six legs. Whether they’re insects or not is up to debate however. Most authorities currently class them as Entognatha, with reference to their internal mouthparts; in contrast to the external mouthparts of insects. However, the other two members of the Entognatha – Protura and Diplura – are just as closely related to springtails as they are to insects.

Another anatomical feature of springtails is the collophore located on the underside of the abdomen, after which they get their scientific name, which means ‘glue piston’. It takes the form of a tube pointing downwards from the ventral side of the first abdominal segment. Originally, it was thought to help to stabilise the animal, although it is now believed to play a part in maintaining the water content of the body.

Springtails get their common name from the furca, a long, forked organ which originates from the end of the abdomen and is often bent under the body. It is used primarily to escape predators, and can fling the springtail at incredible speeds away from danger. However, where and how the animal lands is unpredictable. Some species, such as Ceratophysella bengtssoni, have an inflatable sac on the antennae with which the springtail can adhere to the surface it lands on. Some species have only vestigial furcas or lack one entirely, often in species which live in habitats such as compact soil where the furca would inhibit the movement of the springtail, or those which live near the sea or flowing water, where an unpredictable jump could land them in an even more dangerous situation.

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Brachystomella parvula. Springtails can vary greatly in shape, this being one of the stout, pudgy Poduromorphs.

The best literature for identification is the FSC key written by the late Steve Hopkin, A Key to the Collembola (Springtails) of Britain and Ireland. This provides a complete key to all the described species thought to be present in the British Isles and is relatively recent (2007). Otherwise, there are a few good websites that can be found online, such as www.collembola.org, which has many good-quality images.

If anyone finds and identifies any springtails, I’m sure the co-ordinator of the Collembola Recording Scheme, Dr Peter Shaw, would be happy to receive any records. His details can be found here. And if anyone records any from Surrey, I’d love to hear from you so I can add the records to my growing database. You can contact me using the form under the ‘Feedback/Contact’ page on my blog. I’d also be happy to receive any unidentified specimens in need of ID.

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Willowsia platani (possibly var. nigromaculata). One of the Entomobryomorphs: comparatively long, slender springtails.

Goldeneye, in lichen form

Running backwards into the Devils Dyke Pub to get out of the fierce hail certainly wasn’t the intended end to today’s outing. We had been caught out on a grand scale; a band of completely unforecast precipitation left our clothes so sodden that not even a hot chocolate and four-cheese pizza could warm me up. But was it worth it?

Birders may be used to the sight of a goldeneye floating out on a windswept gravel pit or reservoir at this time of year. Although the diving duck breed in trees, the nesting sites are solely in cavities in larger trunks and at latitudes further north than the UK. So, how many British birders can say that they’ve seen a goldeneye in a tree? I doubt many of them – yet as of this morning I can, but not sensu stricto.

The goldeneye lichen, Teloschistes chrysophthalmus, is named after the bright orange apothecia borne on blue-tinged stalks. The apothecia are disks containing the asci, which in turn contain the spores which will be carried on the wind to colonise new sites. Indeed, this is likely to be how the goldeneye lichen arrived in the UK. In the 19th century there were several sporadic records along the South Coast, and this decreased to only two in the 20th century. Yet, since 2007, recolonisation has been in full swing and there have been records from most South Coast counties along with an outlier in Herefordshire. It is still a fairly rare species, but definitely on the increase. It is not completely known what might be driving the recolonisation. Increasing temperatures could be a factor, yet in the early 19th century when well-established populations could be found in the south, it was relatively much colder than modern times.

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The bright orange apothecia really stood out on this drab, dull day

For this sighting I am indebted to @apeasbrain who first found the lichen last weekend and who provided brilliant directions (only the one individual plant has been found so far, like a needle in a haystack). However, it turned out that despite the lichen being the main instigator for my visit to Devils Dyke, it was not the only highlight. Just past the Hawthorn on which the lichen is growing, the path descends into a copse of Ash trees. On one of these trees I managed to spot some movement, out of the corner of my eye. At first glance I took it to be a ladybird larva, but I knew something wasn’t quite right. On arrival home, I realised it was in fact a pre-adult Endomychus coccineus, known vernacularly as the False Ladybird. This was a species I’d been wanting to see for months, so it’s a bit embarrassing that I didn’t recognise it immediately – but coupled with the Teloschistes, the incredibly painful scramble back to the pub once the hail set in was absolutely worth it.

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Teloschistes chrysophthalmus becomes my 100th lichen and Endomychus coccineus my 250th beetle. Together they put me on 69 new species for the year so far, a good pace I think!

Beluga in the Thames!

Contrary to my normal style, this blog post’s title is a little more self-explanatory than usual. This is so that when I’m scrolling through the archives in fifty years time I’ll be able to instantly recognise what this post will be about: something I’d never even considered possible.

If I was looking ahead to today from this point last week, I would probably be wondering how I’d managed to book a flight to Greenland or Svalbard at such short notice, and why it was a mild 17 degrees at such high latitudes. At the very least, I would be curious as to where I’d sourced my drugs from. I cannot believe that this morning I was enjoying a plate of chips in the warm sun at a table outside the Ship & Lobster on Mark Lane in Gravesend, Kent, while behind me a Beluga surfaced, just behind a barge with the words ‘Working for the Tidal Thames’ inscribed on its side.

The whale was first found by Dave Andrews on Tuesday, and I imagine he must have had the shock of his life when he spotted it. I certainly would have, with this record constituting one of the most southerly records of this species in the world. Belugas have a circumpolar distribution, with the nearest populations to the UK being over 2500km away. I was surprised to find out that this is the 19th sighting of Belugas in UK waters, although they have chiefly been seen in the Hebrides, Shetland and Orkney, with outlying locations being off Northumberland and Northern Ireland, both in 2015.

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The stretch of the Thames where we saw the Beluga

Belugas are interesting among whales as they can easily tolerate brackish and even freshwater. They are quite at home in estuaries and during summer often travel hundreds of kilometres up rivers in search of fish. In the remote polar regions they usually inhabit, this is fairly risk-free. The Thames is something else, however. As you can see from the above photo, residing in the Thames is not without its dangers. During the short while we were watching the sub-adult Beluga, about half-a-dozen vessels passed right over where the Beluga was seen just minutes before including a couple of massive ships.

Although, ship strikes are not the only danger this whale may have to face. There is also, of course, a higher concentration of plastic in the river than it will be used to. If it ingests too much it will die a slow and painful death. No doubt the overall relatively balmy climate will have an effect, although I’m not sure exactly how. But if Belugas weren’t affected by warm temperatures, then they wouldn’t be restricted to such icy climes.

It will be interesting to see how this Beluga’s slight wander will pan out. The best case scenario is that it will be seen swimming downstream and into the North Sea, where its instincts will kick in and it will swim back north to where it ought to be. To finish this blog post, here is a video of the couple of times I managed to record ‘Benny the Beluga’ coming up for air (email subscribers may have to click through to the blog to view the video):