Missing sectors

Missing-sector Orbweb Spider (Zygiella x-notata)

While rummaging around the part of the garden near the house recently, looking for likely suspects to photograph, I came across this spider strolling unsteadily along the windowsill. It was a rather chilly, windy morning, so she might have been a bit cold. For whatever reason, she was in the open rather than hiding away, so I was able to get her picture. This is a Missing-sector Orbweb Spider, named for its habit of leaving an empty section in its otherwise normal orb web. (Think Charlotte's web with the radial lines missing in one of the upper sections.) A single thread crosses this empty section from the center of the web to its edge, where the spider sits in a retreat it has built there. The thread acts as a signal line, with its movement alerting the spider, which is holding the thread between its front legs, to the presence of any prey caught by the web. This line allows the spider to zip quickly to the middle of the web without having to negotiate sticky threads. Interestingly, if the plane of the web varies from the angle of the signal line by more than 40 degrees, the spider doesn't leave a sector missing. Presumably, that's because it can parachute in on the line without having to worry about getting caught in its own web.

In most examples of this species, the pattern on the abdomen is silvery-grey with darker edges; in fact the spider's other common name is Silver-sided Sector Spider. (This particular individual appears to lack that colouring.) The silver comes from very thin crystals of guanine beneath the spider's skin — the same substance as that found in fish scales. While the silver of a fish's scales help to camouflage it from below, scientists aren't sure how such colouring helps spiders.

As with most of the spiders we've been able to identify so far, this one is very common and widespread across Britain. It's found across pretty much all of Europe and the Middle East, as well as along both coasts of North America, throughout the Japanese islands and in other scattered locations in Asia and South America. This species is nearly always found in association with us humans, and we have undoubtedly carried it around the world with us. It's particularly common in the upper corners of window frames and doorways, occasionally venturing as far as roof eaves and fences, or even into garden bushes. It's also regular around boats and docks. Away from humans, it's sometimes found near cave entrances. As the British Arachnological Society posits, perhaps it moved from caves to houses with us!

Checkers

Male Orange-tip (Anthocharis cardamines)

One of the early-season butterflies that has made quite a splash in our garden this spring is the unmistakable Orange-tip (Anthocharis cardamines). Somehow, they weren't on our butterfly list until this spring, though I'm sure we must have seen some before then. This year, however, they've been hard to miss! Mike got the nice snap of the male above; it's certainly easy to see how it got its common name. The female (pictured below) is a bit tougher to identify. From above, she looks very similar to the Small White. Underneath, though, is a different story. The green-and-white checkered pattern (found on the underside of both males and females) is unique among Britain's breeding butterflies, and shared by only a few closely-related species elsewhere in Europe. The Orange-tips are in our garden thanks to our burgeoning stands of Garlic Mustard, which we've left specifically to attract them. Both that and Cuckoo-flower are favoured larval food plants. Other crucifers (members of the cabbage family) are also used to a lesser extent, but caterpillar survival isn't thought to be good on those plants.

Orange-tips are now common and widespread across most of the British Isles, having surged north well into Scotland over the past 30 years. Their range extends throughout Europe and across temperate Asia as far as China. Although they prefer damper habitats, such as the banks of streams and rivers, woodlands and hedgerows, they'll readily visit gardens too. Adults are on the wing between April and July. Females lay their tiny eggs, which turn bright orange as they mature, near the developing seeds of the host plants. When the caterpillars emerge, they eat first their eggshell, and then any nearby unhatched eggs — eliminating the competition. By July, the caterpillars will pupate, remaining encased until the following spring, when they emerge as adults.

Female

Trefoil

Lesser Trefoil (Trifolium dubium)

Right now, the edges of our driveway — and anywhere else the grass is short or non-existent — are covered with the tiny trefoil leaves and little yellow flowers of Lesser Trefoil (Trifolium dubium). Also known as Yellow Suckling Clover, this low-growing annual is a member of the pea family, and has the typical "pea flower",  just on a very small scale. The whole flower head, which consists of a dozen or more flowers, measures a mere 5mm (1/4-inch) across. The plant tolerates a wide range of conditions, but is especially common on lighter, sandy, nutrient-poor soils like we have here. Its hard little seeds are remarkably persistent, with some successfully germinating even 20 years after they were produced. Sadly, just about every source on the internet talks about how to eliminate it from lawns, as if having it there might be a problem (as I suppose it would be if you wanted a putting green instead of some biodiversity). Given that the plant helps to fix nitrogen into the soil, thereby improving it, you'd think people might be willing to tolerate a few plants!

Though native to Europe, Lesser Trefoil has been widely introduced across the world, generally as a contaminant in crop seeds. It's a common and widespread species across Britain. It's similar in appearance to Hop Trefoil, but has smaller flower heads with fewer flowers, and its flowers don't swell as they go to seed, like those of Hop Trefoil do. It blooms from May through August on drier soils, and through October in moister places. The flowers are insect-pollinated, and bees in particular are attracted to them — reason enough to tolerate multiple patches, in our opinion.

Unexpected

Lesser Whitethroat (Sylvia curruca)

Recent sunny mornings have found us perched on the mound that runs along one edge of our property, gazing out across the crop field on the far side of the track out to the main road. There's a reservoir and a small reedbed in that direction, and we've been keeping an eye out for migrants that might be attracted to the two. Between our place and the reservoir, there's an old hedge, with gorse and hawthorn bushes interspersed with a few maples and elders. A few weeks ago, we heard a Lesser Whitethroat (Sylvia curruca) singing from that hedgerow. He cycled back and forth from the reservoir end to the bigger oaks at the hedgerow's near end, always stopping just outside our property. That was true until one day earlier this month, when he was suddenly singing from a dead branch in the wiggly willow tree right in the middle of our garden. (He's in that tree in the photo above). He hung around for a week or so, trying to attract a mate, before apparently moving on. We haven't heard him lately.

Lesser Whitethroats are widespread summer breeders here in Britain, arriving in April and staying through September. The RSPB estimates that there are 74,000 breeding pairs across the UK. They're found across much of Eurasia, spread across habitats ranging from woodland, farmland and grassland to urban and suburban areas. They prefer scrubby areas with plenty of dense cover, particularly thorny trees and shrubs. They're generally skulkers, spending most of their time lurking in the heart of dense bushes. Fortunately, hormones are a wonderful thing, and males trying to set up territories are often (as we saw) a lot showier. When they leave us in the autumn, they head to Africa, Arabia and India for the winter.

Lesser Whitethroats look a bit like smaller, less colourful versions of the Common Whitethroat. Both males and females are greyish-brown above and creamy-grey below, lacking the rufous wings and pinkish chests of their larger cousins. Their heads are grey with darker grey on the cheek, giving them a somewhat "masked" appearance — perhaps appropriate in these days of Covid-19! Their legs are also grey (just about visible in the photo above) rather than pale pinkish, and their white outer tail feathers can be eye-catching when they fly. In spring and summer, they're primarily insectivorous; in autumn, they add berries to their diet to build up their fat reserves. To hear what our bird sounded like, click on the link below; his song is the sporadic short rattle heard five times in the recording.
 

Megan Edwards Crewe · Lesser Whitethroat

Red Campion

Red Campion (Silene dioica)

One of the things that has been blooming like mad in the garden for weeks is Red Campion (Silene dioica), also known as Red Catchfly in North America. It's pushed up a clump that measures nearly a metre in diameter, and displays a mix of pink and white flowers, which may indicate that there's more than one plant involved. White flowers are rare but not unknown on Red Campion; occasionally, mutations cause the loss or suppression of the red pigments. Hairy, oblong leaves grow in pairs on opposite sides of its tall, equally hairy stems. The flower's five, deeply-cut petals are fused at the base, and surrounded by a purplish-brown sheath. Unlike most plants, which have flowers containing both male and female parts, Red Campion flowers are single-sexed, and all the flowers on a particular plant will be that one sex. For example, the plant pictured above is male, with five white, pollen-carrying anthers sprouting from the centre of each flower. The plant blooms from May to July, with fruits developing on female plants from June to August.

This robust but short-lived perennial is typically found in lightly shaded woodlands, but also grows in ditches, grasslands, hedgerows, along roadsides, and in urban areas. Supposedly, it doesn't grow well in dry, sunny gardens, but the one in our garden does precisely exactly that! It's popular with pollinators, attracting a variety of butterflies, moths, bees and long-tongued hoverflies to its pollen-rich (if male), nectar-filled flowers. The tubular flowers prove challenging to shorter tongued bees, but some — like various bumblebees — learn to chew their way through the base of the flower to reach the nectaries. Its boiled roots were formerly used as soap, and the seeds were used to treat snake bite. Red Campion is common and widespread across the British Isles, and northern and central Europe, less so in southern Europe. It has also been widely introduced across North America.

Soft

Soft Brome (Bromus hordeaceus)

One of the new grasses to show up in the garden this year is Common Soft Brome (Bromus hordeaceus) — and it's suddenly fairly abundant along the foot of the mound that runs along one side of our property. This annual (occasionally biennial) grass is said to be Britain's most common Bromus species, so it's a bit surprising we haven't recorded it before now. I'm guessing we might just have overlooked it. It's a grass of open habitats, including meadows, roadsides, dunes and "waste places", and is particularly common in human-managed habitats. Its tufts of grey-green leaves can be found year-round, but its compact flower heads, and the ensuing seeds that develop, are seen from May to August. The oval flower heads, and the long, stiff bristles that extend from their tips, are distinctive. It's a relatively tall grass, sometimes reaching a metre in height. Highly adaptable, it tolerates shade, full sun, drought, browsing pressure, fire, cutting and more.

Though native to Europe, Common Soft Brome has been widely introduced across North and South America, Asia, Australia and some Pacific islands. In North America, it's known as "bull grass", "soft chess" or "soft cheat". It's rated as a good forage grass, and has also been used for erosion control. However, it's a weed of cereal and clover crops, and can cause conservation problems in areas where it has been introduced. Because of this, it's widely considered to be an invasive plant, sometimes even within its native range. However, it's not causing any problems here (yet anyway), so we're happy to let it be.

Rust

Alexanders Rust (Puccinia smyrnii)

In 1872, mathematician Augustus de Morgan wrote, in his poem "Siphonaptera":

Great fleas have little fleas upon their backs to bite 'em,  

And little fleas have lesser fleas, and so ad infinitum.

And so it is with plants too; even our robust Alexanders plants don't escape. Many carry patches of the fungus Alexanders Rust (Puccinia smyrnii), a species found only on Alexanders. This rust, which can vary from yellow to bright orange in colour, attacks both the upper and lower surfaces of leaves, as well as the plant's stem, creating large pustules and extensive swelling. As it's specific to Alexanders, it's restricted to those parts of Britain (plus Europe and North Africa) where the plant occurs. In the UK, that means it's most prevalent along the coasts of England and Wales, though it's spreading inland along with its host plant.

Rosemary

Common Rosemary (Salvia rosmarinus)

One of the many plants in the garden making the pollinators happy is a Common Rosemary (Salvia rosmarinus) bush in the herb plot. Now in its second year, it's currently covered with pale lavender flowers that the bees — particularly the Hairy-footed Flower Bees — seem to find irresistible. It's a plant that's well-known throughout much of the world, thanks to its long history as a cooking herb. Native to the Mediterranean region and to Asia, it was brought to the British Isles centuries ago, though whether it arrived with the Romans is open to debate. There are no reliable records of it being here until the 8th century. At that point, Charlemagne, Emperor of the Holy Roman empire, ordered that it be grown in monastic gardens and farms. It was carried to the New World by European settlers in the early 1600s, and subsequently spread across most of both North and South America. It's now found on every continent except Antarctica, as well as on many islands. It has the potential to become invasive, and is causing problems as such in Cuba.

A long-lived, woody perennial, Common Rosemary flowers primarily from June to September, though it's also known to bloom outside its main flowering season; ours started in April this year, for example. Those planted in warm climates may bloom year-round. It grows primarily in dry, sandy or rocky soils, so is finding the gritty soil of North Norfolk's glacial till quite to its liking. And fortunately, it doesn't seem to mind the occasional salty wind off the North Sea. It survives in places with mild winters, but doesn't do well if the temperatures are regularly below freezing. I guess that explains why it doesn't grow in Scandanavia!

A close-up of the flowers

Tree Bumblebee

Tree Bumblebee (Bombus hypnorum)

As we emptied our moth trap out a couple of weeks ago, we found a cold and dozy bumblebee among the egg cartons piled there. Like the moths she shared the trap with, she'd obviously been drawn in by the light. We boxed her up and carried her out to a stump in the sun, and set her there to warm up, which she quickly did. Soon, she was maneuvering herself to get a better angle towards to the sun (i.e. exposing more of her black self to its rays) and within minutes she zoomed off — circling back a few times to check out the stump as a potential nesting site. Unlike the Buff-tailed Bumblebee that I profiled a few weeks ago, this one has a bright gingery-brown thorax (the part of the bee just behind the head). The female's black abdomen has a white tip. Males would also have some gingery-brown hairs at the ventral end of the abdomen — that is, the end of the abdomen closest to the head. The combination of gingery thorax and white tail tip is unique among British bumblebees.

The Tree Bumblebee is a relatively new arrival to the UK, first recorded in southern England in 2001. It's been rapidly pushing north ever since, arriving in Norfolk in 2008, and now regular well into Scotland. Amazingly, it's now one of the commonest bumblebees in the British Isles. Elsewhere, it's found throughout mainland Europe and Asia, as far north as the Arctic Circle. It's one of the earliest bumblebees to emerge in the spring, flying from March through July. It prefers to feed at pendant-shaped flowers; that said, it's not terribly picky and has been recorded feeding at more than 100 different plant species. As an early-emerging species, it has become particularly important in the pollination of orchards, which have been struggling with the decline of honeybees. Though naturally a woodland edge species, the Tree Bumblebee has quickly adapted to us humans, and will happily use a nest box or the gap under a roof tile as readily as a tree hole for its nest site. Because of their unique nesting spot choices (other bumblebees nest underground), Tree Bumblebees don't appear to be adversely impacting Britain's other bumblebee species. We saw a few checking out our already-occupied nest boxes earlier this year, but fortunately, the Eurasian Blue Tits prevailed.

Bee-utifully Useless

Cuckooflower (Cardamine pratensis) - the double-flowered form

Sprinkled through the grass on one side of our house are the lovely pale pink flower spikes of the Cuckooflower (Cardamine pratensis). Normally, this sure sign of spring has four flower petals, but our plants, which are a "doubled" variety, have eight. This may be natural, but it may also be the result of horticultural tinkering; plant people are forever trying to "improve" on nature! The resulting flowers are undeniably pretty, but they are completely useless for pollinating insects. As you can clearly see in the above picture, all of the plant's reproductive bits (which should be in the centre of the flower) have been replaced by petals. And without stamens and pistils, there will be no nectar and pollen. The doubled plants aren't completely without merit, however. In addition to our enjoyment of their attractive flowers, they can also serve as food for the caterpillars of Orange-tip and Green-veined White butterflies.

To be honest, we're a bit surprised to have Cuckooflower in the garden at all. Though common and widespread across the British Isles (as well as most of continental Europe and western Asia), it's typically found in damp places such as wet meadows, riverbanks and ditches, and our property is anything but damp. But it seems to be growing happily enough, with even more plants apparent this year than last — presumably because Mike has carefully left a large unmown stretch of grass around them. Cuckooflower gets its name from the timing of its flowering. It blooms from April to June, first appearing at roughly the same time that Common Cuckoos return to Britain and start to sing. Its young leaves have a peppery taste and were used as substitute for watercress in the past. However, picking of the plant was considered unlucky (the plant was reputed to be sacred to the fairies), so it was never widely used medicinally.

A few of the scattered plants

Hebrew Character

Hebrew Character (Orthosia gothica)

One of the very few species of moth we've caught in our trap so far this year is the Hebrew Character (Orthosia gothica). The species gets its name from the distinctive black mark on its wings — a shape which resembles nun, one of the characters in the Hebrew alphabet. This mark is unique among spring-flying moths, making it an easy species to identify. It's an early-season moth, generally overwintering underground as a pupa (the stage of its life between caterpillar and adult) and emerging to fly as an adult in March and April. In mild years, some can even be found in late autumn or winter. Common and widespread throughout the British Isles and across Europe, they're found in virtually every habitat. Adults and larvae are nocturnal, with the former often feeding at willow flowers, and the latter feasting on the buds and leaves a number of shrubs, trees and herbaceous plants. We'll be keeping an eye out for the caterpillars.

Vanilla

Sweet Vernal Grass (Anthoxanthum odoratum)

With the sun and warmth we've had of late (the last few days notwithstanding) our meadow is coming along in leaps and bounds. Among the first of the grasses to flower is Sweet Vernal Grass (Anthoxanthum odoratum), a tidy, sweet-smelling species native to Europe, Asia and northern Africa. Its oblong flowerheads appear from April to June atop stiff stalks that rise from tufts of broad, flat leaves. We've only got a small patch of it, towards the far end of the garden, and one additional clump, in a host of Spanish Bluebells near the garage. Compared to the grasses that will mature later in the summer, this one is quite small, maxing out at 10-15 inches (25-40 cm). It's a perennial, but a relatively short-lived one. Widespread across the UK (and the rest of Europe), it grows freely in a variety of habitats. It's also common in much of the US.

In full flower

Sweet Vernal Grass has been widely introduced in the US as a lawn and grazing grass. Because of its vanilla-like flavour (and fresh cut-hay smell), it was once a favoured chewing grass. It's sometimes used as a flavouring (in some Russian brandies, for example), and reputedly, Norwegians used to put dried plants with stored clothes to keep them smelling sweet. We're particularly happy to have it in our pocket meadow because it's the larval food plant for a host of butterflies that we've seen in the garden: Meadow Brown, Ringlet, Speckled Wood, Gatekeeper, Small Skipper, and Essex Skipper among them. Unfortunately, its pollen is said to be particularly aggravating to those who suffer from hayfever — not good news for Mike! 

Sweet Vernal Grass in the "meadow"