Leggy

Female Opilio canestrinii

For several days in a row a couple of weeks ago, I found this female harvestman (harvestwoman?) sprawled out on a nettle leaf in the garden. Did she stay there the whole time, digesting a particularly big meal? Or had she made sorties and returned to a favoured spot? So many mysteries! She's an Opilio canestrinii, one of Britain's longer-legged harvestman species. The two rows of alternating dark and light bars on her back (see the picture above), her very long dark legs, and her white operculum (the little turret that her eyes sit in) help to identify her. Males are smaller-bodied, and more uniformly red-orange in colour. This is a newly-arrived species in Great Britain. First recorded in the Thames Valley in 1999, it has spread rapidly and is now found across England and Wales. In 2011, it was found in Scotland, and has since been spreading quickly from that initial location. Intriguingly, it wasn't known in Europe until the mid-1900s, when it was found in Italy; since then, its range has expanded to cover most of western Europe. In some places (i.e. the Netherlands), its arrival has led to the extinction of native Opilio species. Let's hope that doesn't happen here!

Quicksilver

Silver-washed Fritillery (Argynnis paphia) with Peacock (Aglais io) in the background

On a whirlwind afternoon last month, we recorded three new species of butterfly for the property. They were part of a big influx that occurred over several days, pushed in our direction by warm southerly winds and enticed to the garden by a plethora of blooming Buddleia bushes. Among the multitude of Peacocks, Red Admirals and Small Tortoiseshells that were sprinkled across the flower spikes, we spotted a suspiciously orange flash, which resolved itself into this slightly battered but still handsome male Silver-washed Fritillery (Argynnis paphis) – a rare visitor to our corner of England. You can tell he's a male by the long dark streaks on his forewing; these are his "sex brands". When he's courting a female, he dazzles her with his acrobatics, flying loops above, in front of, and under her as she continues to fly in a straight line. If she's impressed enough to land, he shakes loose a shower of scented scales from those sex brands to further convince her of his desirability. At first glance it seems odd to call this butterfly "silver-washed", given that it's orange and black. The steaks which give it its common name are actually on the underside of its hindwing, and are only visible when the butterfly folds its wings.

This isn't a common species in our part of England. Typically, it's found in the southern and western corners of Britain, with only the occasional strays making it futher north and east. It's primarily a woodland species, breeding in shadier parts of the forest, but moving to more open areas to feed. Adults fly from mid-June through August. Once she's mated, a female will lay her eggs in moss or bark crevices near colonies of Common Dog-violet (Viola riviniana). Though they hatch in the fall, the larvae immediately go into hibernation. The following spring, they'll emerge to feed on the newly-flowering violets. The species underwent a big population decline in the 1900s, but in recent decades have started to expand their range again. Here's hoping they become more common again in our part of the country!

Ermine

White Ermine (Spilosoma lubricipeda) caterpillar

The spikey-looking caterpillar pictured above is the very hairy offspring of one of our regular moth visitors – a White Ermine (Spilosoma lubricipeda). I spotted it humping its way rapidly through the longer grass at the edge of one of the garden paths last week. In this case, the "racing stripe" proved apt! It must have been moving from one food plant to another, and given its preference for docks and nettles, it had certainly picked the right corner of the garden to investigate. Adults, which fly from May to July, are long gone. Earlier in the summer though, they're common and widespread in most habitat types (except wetlands) across much of the British Isles, as well as throughout temperate Europe and Asia. They're pretty distinctive: creamy white all over with black antennae and varying numbers of black spots. Those in Scotland are said to be sometimes buffy or brown rather than creamy. They have the rather endearing habit of playing dead if disturbed during the day, dropping to the ground and lying on their backs with their legs all folded. They're full of alkaloids (which make them at best unpalatable and at worst, potentially toxic to anything trying to eat them) and presumably can emit some chemical scent to warn predators of that. Larvae are full of alkaloids too, and also rely on their bristly hairs to help make them an unappealing meal. They overwinter as pupae in leaf litter, emerging in late spring as adults. Here's hoping this youngster makes it to next year!

Adult, in mid-June

Wasp mimic

Chrysotoxum bicinctum

One of the more distinctive hoverflies to visit our garden is the eye-catching Chrysotoxum bicinctum. It's a wasp mimic – and quite a good one at that. The combination of the two yellow bands across its black body, its long antennae, and the chocolate-brown spots on its wings is diagnostic; no other UK hoverfly shares those features. We often find these hoverflies on the Field Bindweed flowers along one edge of the garden. They prefer sheltered grassy areas, especially those near shrubs or trees. Adults fly from May to September, peaking from mid-June to August. Surprisingly (considering that they're widespread across lowland England, and occur throughout Wales and as far north as the north coast of Scotland), little else is known about their biology. The larvae are thought to be associated with ant nests, where they may feed on root aphids being "farmed" by the ants. There's so much still to be learned about many of the world's smaller creatures!

Wall

Wall Brown (Lasiommata megera)

While rambling around the garden on a recent afternoon, I spotted an unfamiliar butterfly resting on a blown thistle head. It looked a bit like a Gatekeeper, but with a lot of extra spots and barring. Clearly, this was something new! I snapped a few pictures and went in search of Mike for an ID. One look brought him scuttling out with his own camera. It's a Wall Brown (Lasiommata megera), a widely distributed but seriously declining species here in the UK. Since the late 1970s, its numbers have dropped by more than 75%, making it one of the island's most imperiled butterflies. It's clinging on along the coasts of England, Wales and Ireland, and in southern Scotland, but has largely disappeared from the UK's interior. And it's not common anywhere now, with only small numbers seen in most places. Wall Brown caterpillars feed on various grasses (including Common Cock's-foot (Dactylis glomerata) and Yorkshire Fog), so our pocket meadow (which has plenty of both) might prove appealing if this male managed to find a female. Wall Browns are named for their habit of basking on walls and other stony places. This one moved from its thistle to our greenhouse door later in the afternoon, the better to catch the sun's rays. Adults fly from May to October, so we could theoretically see another one or two. Given their small numbers, that would definitely be a treat!

Redeye

Small Redeye (Erythromma viridulum)

The pond does it again! Early last month, Mike spotted a single Small Redeye – a little corker of a damselfly that is a relatively recent arrival to the UK. He called to me (I was photographing hoverflies nearby) but by the time I'd scuttled over, it was already gone. Fast forward a few days, and a trio of males jousted over the lily pads. Fast forward another week or two, and there were dozens of them. On one sunny afternoon in the middle of the month, we counted 35 pairs busily egg-laying on Soft Hornwort (Ceratophyllum submersum) below the pond's surface, with assorted single males frantically trying to get in on the action. Females were regularly submerged underwater for 5 to 10 minutes at a time, methodically placing each egg on a separate bit of plant; the males didn't let go of their grip on "their" female's neck until she was done. After a few frenzied days of activity, they all disappeared, with only a few scattered corpses to show they'd ever been there.

Small Redeyes only arrived in the UK in 1999. From their first toehold, they expanded rapidly across the Isle of Wight and southeastern England, and have now reached as far west as Devon and as far north as North Yorkshire. Their small size, pale pterostigmas (coloured spots near the tips of their wings), pale gray legs and dark abdomen with a blue "tail light" near the end (smaller in females) help to distinguish them from other similar species. And the bright red eyeballs of the males are hard to miss. They fly primarily from June to August, though they can be seen as early as May and as late as September. They frequent ponds, lakes and ditches, and (according to the British Dragonfly Society's website) "seem to be associated with floating vegetation such as Hornwort and Water Milfoil". We can certainly attest to that!

Just a few of the many pairs egg-laying in the pond