Category: Science

TL:DR – Update on moth species observed as part of my citizen science work on Lepidoptera.

The summer seemed sluggish, as it were, but last night’s lighting up session brought around 200+ moths of about 50 species to the scientific trap. Most of them I had seen and photographed before, but in the absence of novelty I will always try something creative with some of the ones I see, so these are all Summer 2022 photos of mostly moths I’ve snapped before, with one or two exceptions. As of this morning, I’ve recorded 30 species to the garden that I have not seen in previous years.

I went looking for Chalkhill Blue at Devil’s Dyke, Cambridgeshire, this morning, having seen several hundred there this time last year. There must’ve been 1000 or so today out and about on the banks of the Dyke and the chalky footpath. There were also dozens of Marbled White, a dozen or so Dark Green Fritillary, and several Brimstone butterfly, a few skippers (Small mainly), lots of Cabbage B*st*rds, and just one solitary male Oak Eggar moth. He has something of the Donnie Darko about him, this one, I’d say…

The moth’s name comes from its chrysalis looking like an acorn and the “enormous” eggs the females lay. The males are day fliers, the females are active at night. Those antennae! Oh my!

The Oak Eggar (Lasiocampa quercus) is a species of moth belonging to the family Lasiocampidae, which are commonly referred to as “eggars”, their eggs are large and resemble acorns hence the name. The moth doesn’t really have an association with oaks. These moths are found throughout Europe, including the United Kingdom, and are also present in parts of Asia.

The Oak Eggar is a medium-sized moth with a wingspan that ranges from 45 to 70mm. The wings are typically a yellowish-brown colour with darker brown or greyish-brown markings. The males have feathery antennae that are used to detect pheromones released by the female moths as a sex attractant.

An unassuming moth new to me, Carnation Tortrix, Cacoecimorpha pronubana (Hübner, [1799])

The Tortrix moths, not to be confused with a potato chip product in Guatemala, are so-called because the larvae of many species of Tortricidae twist leaves around themselves. Tortus is the past participle of the Latin verb torqu?re, to twist.

The moth’s hindwings are orange, you can just see a hint of that in the way this one is resting. That Latin verb is also the root of the motoring term “torque” meaning twisting, or rotational, force.

Also had Timothy Tortrix, Aphelia paleana (Hübner, 1793) in the garden last night. First time I’ve noted and photographed these species.

UPDATE: I’d almost given up hope on the local Purple Hairstreaks for 2024, but had a last look at the oaks on the outer edge of Manor Farm Wood facing out over the Cottenham Lode and spotted one, then a couple more. Six sightings in all, so perhaps 3-4 individuals. Probably too late for White-letter of which there was no sign.

I found a colony of White-letter Hairstreak in the middle of Manor Farm Wood, Rampton. I don’t think I’ve heard of anyone mentioning this species in this woodland before. It’s a relatively young woodland. The butterflies were emerging from a tall blackthorn and coming fairly low to nectar on bramble and flitting back into the blackthorn. There are elms in the vicinity, the foodplant of this species’ larvae.

I was then surprised to see another hairstreak flying in the top of a willow tree on the Lode-side edge of the same woodland – Purple Hairstreak!

As I watched, I counted perhaps 9 or 10 Purple Hairstreaks and got photos of a few when they settled. I don’t believe either species have been noted here before. Certainly, Ed Pollard, the County Butterfly Recorder was unaware of this wood and had not had records of butterflies there until I logged mine with him.

Les King Wood back towards Cottenham from this spot had a report of Green Hairstreak in 2020 (from Martin Fowlie) and I caught up with that species there in 2021, but I have not seen them there summer of 2022, sadly. UPDATE: 29 Apr 2023. But not seen any in 2024.

I have seen lots of Green HS along Devil’s Dyke in Cambridgeshire when I went chasing the Adonis Blue and Dark Green Fritillary.

I have only previously seen Purple Hairstreak in Woodwalton Fen NNR (2021 and 2022) and Brampton Wood (2022), so as with the White-letter Hairstreaks, I was quite surprised to see them in this relatively young woodland so close to home.

It is wholly unlikely that the most uncolonial of our hairstreaks, the Black Hairstreak, will turn up here, restricted locally to Brampton Wood and Monk’s Wood as they seem to be.

UK hairstreaks I have photographed so far

White-letter Hairstreak (2021) – Satyrium w-album (Knoch, 1782)
Green Hairstreak (2021) – Callophrys rubi (Linnaeus, 1758)
Purple Hairstreak (2021) – Favonius quercus (Linnaeus, 1758)
Black Hairstreak (2022) – Satyrium pruni (Linnaeus, 1758)

Ilex Hairstreak (2024, Greece) – Satyrium ilicis
Blue-spot Hairstreak (2024, Greece) – Satyrium spini
Sloe Hairstreak (2024, Greece) – Satyrium acaciae

I am yet to see Brown Hairstreak, the largest British hairstreak butterfly, and the only one missing from this list. It is scarce and found only in the South and South-West and Wales in the UK. UPDATE: July 2024, now present at RSPB Frampton Marsh near Dartford.

Quoting the UK’s Butterfly Conservation: The Oxford and Ampthill Clays are the only place in the UK where all five of the hairstreak family of butterflies can be found.

There are seventeen “tribes” of hairstreak worldwide amounting to dozens of other species. Some of the Theclinae (the hairstreaks subfamily) are known as elfins.

UPDATE: June 2024 – Butterflying holiday in northern Greece. Saw Green, Purple, White-letter Hairstreak, and added Ilex, Sloe, and Blue-dot Hairstreak to my international list, as well as many other butterflies.

I spotted a White-letter Hairstreak in our local woodland (Manor Farm Wood, Rampton) in the middle of June 2022. Having only previously seen it at Overhall Grove flying at the tops of elms, I was a little surprised to see this species, of which I eventually counted 15 in the space of an hour or so (21 a couple of days later).

It’s a “hairstreak” butterfly, note the white streaks on the underside of its wings, but also note that towards the termen of the wings the white streaks form what might whimsically be perceived as a “W” or an “M” depending on your reading angle. Hence the scientific name: Satyrium w-album.

The adults nectar on bramble flowers but its larval foodplant is the elm. Obviously, since the 1920s, elms have commonly succumbed to Dutch Elm disease and so the WL-HS has not been as widespread nor as common as it perhaps once was when elms were everywhere. It’s making a bit of a comeback and not so localise nor non-colonial as its cousin the Black Hairstreak. From a quick scan of the records for S. w-album on iRecord it looks like they are seen in some disparate places across Cambridgeshire, but I think my Rampton record if the first noted on that site.

I saw my first WL-HS in Overhall Grove in 2021 but only encountered the B-HS for the first time at Monk’s Wood and then Brampton Park. The B-HS inhabits old woodland with well-established blackthorn bushes growing in particularly peaty earth. In the whole of the UK there is only a narrow strip of such habitat that stretches from north of Cambridge South-west to Oxford, and one or two other spots. Monk’s Wood and Brampton Wood are at the North-eastern end of this strip of land. There are perhaps hundreds if not thousands of B-HS at Brampton which has an abundance of blackthorn. These two woodlands are the oldest in the county of Cambridgeshire.

I have now added a sixth butterfly species to the list I’ve photographed this year for the first time, beating the total of five new species last year. The Small Blue (Cupido minimus) joins Adonis Blue, Black Hairstreak, Grizzled Skipper, Wall, and White Admiral on my list.

The Small Blue has to be the most brown of the Blues. The male has a bit of a bluish suffusion close to the body, but is basically a brown butterfly like the female. The wings have a white fringe and the underside has black spots that are unlike those of the other blues and resemble the Holly Blue but with beige as the ground colour rather than blue. However, its vernacular name rings true in the adjective “Small”. This is definitely the UK’s smallest butterfly. The scientific binomial might be translated whimsically as being “the smallest Cupid” but strictly speaking translates from the Latin as “a desire for the least”.

I saw the Small Blue for the first time on a visit to Trumpington Meadows nature reserve not far from Addenbrooke’s hospital in Cambridge. A Cambs Wildlife Trust rep there, who goes by the twitter handle @HarryHedgehog7, pointed me to a small footbridge that crosses the M11 motorway from the Meadows to an additional chunk of wild area beyond the old crop research site. There is abundant Kidney Vetch (Anthyllis vulneraria, also known as woundwort), which is one of the larval foodplants, although the caterpillars are cannabilistic and will eat each other, and while the colony did not appear to number in the hundreds as can occur, there were at least a couple of dozen that showed their true colours among the vetch.

Also seen, Common Blue (not that common, but the males are definitely blue), Small Tortoiseshell (quite a large butterfly, but its pattern is reminiscent of a coloured-in tortoiseshell), Large, Small, and Essex Skipper, Marbled White (which are sort of marbled but they’re actually a type of “Brown” Satyrinid butterfly), and a lot of Six-spot Burnet moths, which definitely have six spots on each wing.

Incidentally, the M11 is an arterial road that connects Cambridge with London, one might wonder whether the Cambridge-educated politicians and civil servants had the public’s interest or their own travel interest at heart when this road was first planned…

In my 2021/2022 quest to see and photograph more butterflies, especially species I’ve not seen before, I’ve been monitoring the Cambs and Essex butterfly sightings page. In 2021, I clocked several new species (Chalkhill Blue, Dark Green Fritillary, Green Hairstreak, Purple Emperor, Purple Hairstreak, and White-letter Hairstreak) and so far this year another five: Adonis Blue, Black Hairstreak, Eurasian White Admiral, Grizzled Skipper, and Wall.

Among the sites visited are Monk’s Wood, Overhall Grove, Waresley Wood, Hayley Wood, Woodwalton Fen NNR, and Woodwalton Marsh and several others. This week, I also discovered a woodland closer to home, The Edwards Woodland in Dry Drayton. It was planted in 2005 on a 14-acre plot owned by the late Sir Robert Edwards, Nobel laureate and co-pioneer with Patrick Steptoe of IVF as discussed here.

The Woodland backs on to the north-east side of Madingley Road between Dry Drayton and Madingley. Reports on the Cambs & Essex site suggested Marbled White and some Clouded Yellow might be present. I saw lots of Marbled White, Ringlet, and Meadow Brown on my visit, but sadly no Clouded Yellow (I had seen that species on the former patch of wildflower meadow adjacent to farmland at Waresley Wood up from Brown’s Piece in 2020).

There are only now a handful of species I will be able to see fresh to me in our neighbourhood, without having too big a carbon footprint.

I’ve been making a concerted effort in 2022 to see more of the quite limited number of butterflies we have native in the UK (I’m up to 36 so far, second season of trying harder). Have now added Eurasian White Admiral to the list thanks to a visit to Brampton Wood not far up the road in Cambridgeshire.

Brampton isn’t too far from Monk’s Wood, which I visited in May to see the newly emerged Black Hairstreak for the first time. It must be noted that there are hundreds and hundreds, perhaps thousands of Black Hairstreak at Monks Wood but perhaps an order of magnitude fewer there than at Brampton. Brampton is the second oldest woodland after Monks in Cambridgeshire but has vast acreages of blackthorn, the larval footplant of that species.

Saw lots of Black Hairstreak, Satyrium pruni, at Brampton Wood, several dozen, perhaps. It’s a rather rare butterfly restricted to a clay-soiled corridor from Oxon through Northants and into Cambs the larvae of which feed only on well-established blackthorn and the adults of which rarely venture a few metres from where they emerge from their pupae.

Given the surveys carried out by wardens there on five small patches of blackthorn and the several hundred acres of blackthorn not surveyed it is likely that there are several hundred thousand of this incredibly rare butterfly on this site.

Lots of Silver-washed Fritillary, Argynnis paphia, at Brampton Wood too.

This is a male of the moth species Nemophora metallica. I’ve written about them on the blog several times over the last couple of years.

Those “horns” are the male’s antennae. They can be up to three times as long as the moth’s forewings. The female’s antennae are half the length. The species loves a bit of Field Scabious (Knautia arvensis) it being the larval foodplant. The dayflying Brassy Longhorn is found in the South of England and across East Anglia generally where Field Scabious grows. They are on the wing in June and July.

Thankfully, last year I managed to persuade the Environment Agency not to prematurely mow the patch along the Cottenham Lode where this species seemed to be thriving these past couple of summers. I hope the EA sticks to its promise again this year, so these little beasties have a better chance of reproducing and the scabious of setting seed. The next step is to persuade the EA to halt all spring/summer mowing of the banks of the lodes so that other invertebrate and botanical species might get more than a foothold. Obviously, the Agency has to consider water flow as the lodes are drainage ditches that criss-cross the Fens. That said, there is no obvious need to remove vegetation so brutally as they often do in the spring/summer if at all.

I’ve taken a number of trips to Devil’s Dyke, Cambridgeshire in the last couple of years, tramping back and forth along the chalky ridge looking for butterflies. In the summer time, when the weather is fine you can almost reach right up and touch them. Saw my first Dark Green Fritillaries and Chalkhill Blues there in 2021 and my first Adonis Blue in 2022 (an unofficially introduced species).

9th June I walked (150 minutes from 10am) from the car park at the Newmarket July Racecourse section to the A14 break and kept a tally of the Lepidoptera I saw, posted data to Cambs&Essex page:

Butterflies

Marbled White 54 (actually one of the “Browns” – Satyrinae
Small Tortoiseshell 7
Dark Green Fritillary 16
Green Hairstreak 3
Common Blue 5
Meadow Brown 10
Large Skipper 5
Small Heath 8
Red Admiral 3
Large White 1
Brimstone 3

Moths