Thursday, 28 June 2012

Orchids and grasses (and a moth)

My local Spotted Orchids have started to flower - albeit a bit later than usual. The three main 'species' that I have locally are:

  • Common Spotted Orchid (CSO) - Dactylorhiza fuchsii
  • Heath Spotted Orchid (HSO) - Dactylorhiza maculata
  • Northern Marsh Orchid (NMO) - Dactylorhiza purpurella
These three freely hybridise with each other, and the hybrids back cross with the parents and with the other hybrids, so it is very rare to find a 'pure' or clean specimen anywhere: each specimen is likely to bear a component of each of the species in varying proportions. For that reason, the taxonomy of the two spotted orchids keeps changing, with them being variously described as species, subspecies or variants. But I just describe them all as hybrid spotted orchids. I recently had a long conversation with a leading orchid specialist, and when I asked him why we continue to try and name each specimen as A), B) or C), he said "it's just because we like to give different names to things that look different from each other, but really they're all hybrids".

I also have a suspicion that some of the variation is caused by the very local microclimate, for example if the orchid is standing in water or has dry feet. I generally find that specimens in water look more like HSO, but drier ones look more like CSO. The natural assumption is that HSO prefers water, and CSO does not, but if the water dries out for any reason, then the specimen that looked like HSO one year will look more like CSO the next year. I call these variations 'ecomorphs'.

Hybrid Spotted Orchid
That first one has features of CSO (the long tooth at the front lobe of the flower) and NMO (the overall colour is quite dark). The edges of the lip are slightly frilled, so there's some HSO in there, too.

And here's another:

Hybrid Spotted Orchid
That one has stronger frills and a paler colour, so I'd say 50/50 HSO and CSO.

These specimens were photographed at their best: the lower flowers have just opened and the higher flowers are still buds. When the flowers are all open, I think the plant looks less attractive.

I'll show more as I find them.

Grasses can be fun to identify, and the good news is that although the initial identification might be tricky, many species are readily identifiable in the field. One key feature is the 'ligule', which is formed where the leaf touches the stem:

Long, pointed ligule of Rough Meadow Grass - Poa trivialis

The long, pointed, ligule in the above specimen points us to Rough Meadow Grass - Poa trivialis.

Here's the grass:

Poa trivialis - Rough Meadow Grass
Crested Dogstail is easily identified by the one-sided nature of the seedhead (although I did manage to mis-identify it on another blog the other day):
Crested Dogstail
Cocksfoot is very recognisable:
While we're on Cocksfoot, I'll show this picture of one of the 'Minor' moths. There are three Minor species which are extremely difficult to separate, so unless we capture and kill them, we have to record them as 'Minor agg.':
Minor agg. moth
Minors use Cocksfoot grass as a food, living inside the stems when at the larval stage.

Yorkshire Fog must be the most common grass in this area: I find it in all but the wettest environments:

Yorkshire Fog
I just noticed the Rye-grass at the front left of the image.

The flowers of Meadowsweet have just opened and their perfume will dominate much of the hedgerow for the next couple of months:

Meadowsweet must be particularly nutritious: there are many species of insect and fungus which feed on all parts of the plant.

Now: hands up all those who ignored (or missed!) the Puccinia graminis rust on the Poa.

I was recently invited to talk about my blog by Nature Center Magazine. You can see the interview here. Thanks to Emma for that.

Tuesday, 26 June 2012

Opportunistic shots

The weather has continued to be cold or dull or wet, or all three at the same time, but I suppose it isn't only us this year.

Scaeva pyrastri is thought to be a migrant hoverfly - at least for the first generation - in Ireland, but I suspect that as we get warmer, then it might well join the growing list of insects that have become winter-resident, like the Red Admiral butterfly, for example. I was just saying the other day that when I was younger, books seemed to have facts in them, nowadays they seem to contain mere guidelines, because so much is changing so quickly.

I spotted this female Scaeva pyrastri hoverfly as she examined each flower stem and seedhead for aphids:

Female Scaeva pyrastri hoverfly ovipositing

Every so often she would stop and lay an egg in amongst any aphids she spotted.

I checked one batch of aphids after she had moved on, and sure enough, I could see the egg - apparently directly on top of an aphid - arrowed in this shot:

Scaeva pyrastri egg (arrowed)
Male hoverflies are known to hover for a variety of reasons, such as protecting territory or showing off their skills to attract a mate, but this female was hovering very accurately as she minutely examined the flower stems and seedheads from around 10mm away. The Small Heath butterfly is very particular about its habitat: it likes heathy areas with shorter grass, but I'm sure it has some other requirement that we don't know about, because many apparently suitable habitats are ignored by them. I had always thought that one particular area on my patch was suitable, but it was only after 8 years of searching that I found a single specimen there last year. A couple of sightings at the same location this year - including the one in the shot - suggests that a colony has now been established:

Small Heath butterfly
It's a lovely little butterfly, and a welcome addition to my local list.

Syritta pipiens is readily recognised by the inflated thighs on the rear legs:

The hoverfly Syritta pipiens, female
A few moths have been brave enough to beat the rain, although reports of populations are far lower than normal, sometimes as low as 10% of the expected numbers. The Hawkmoths are our most stunning moths, and I was fortunate that this Poplar Hawkmoth came to light:

Poplar Hawkmoth

These are as large as smaller bats, and on a 17" screen at 1024 x 768, that picture isn't much larger than life size. The Poplar Hawkmoth larva usually feeds on Poplar, but hereabouts it will be Willow. Notice that the wings of this species at rest are held in a very unusual configuration, with the rear wings ahead of the front wings.

The Common White Wave is a handsome little moth:

Common White Wave moth

This species is distinguished from the Common Wave by the almost-straight rear grey lines on the forewing.

This weevil caused me a bit of pain during the identification process. Most web references say that it is associated with Dog's Mercury, which doesn't grow around here. It keyed quite quickly to Barynotus moerens, but with all the web references stating that it was associated with a single plant, I retried the identification several times to see where I had gone wrong. 

The weevil Barynotus moerens
After much angst, I found that it is also associated with Ground Ivy, which we have in abundance around the patch. I think many websites (and some reference books) just copy what they read elsewhere without examining the facts.

New to my species list.

Wednesday, 20 June 2012

Old and new

The weather continues to be odd: very heavy showers interspersed with brief (and unexpected) blue gaps in the cloud.

Plants are making their usual growth, but insects are finding it hard to get going, since they must shelter from the rain and emerge only when it's safe to do so.

My first shot today is a hoverfly which is highly distinctive and new to me:

The hoverfly Chrysotoxum bicinctum
Chrysotoxum bicinctum is easily recognised by the wide yellow bands on tergites 2 and 4, with an occasional thin band on tergite 3. The front half of the wings are dark brown, although that's difficult to see from the shot above. The biology of Chrysotoxum sp. is largely unknown, but the larvae appear to be associated with aphids, particularly those in association with ants. There is a lot out there that we just don't know enough about. Handsome beast, anyway.

The next specimen is probably new to me as well, but without capturing the specimen I can't be sure.

Platycheirus ?fulviventris

It's certainly Platycheirus sp. but I couldn't get a good enough view of the front feet to confirm, although I did get a good view of the dark yellow/orange abdominal patches in flight. Looks to be Platycheirus fulviventris, but could be a couple of others.

The effects of rain are clear in this next shot of what appears to be the solitary bee Andrena cineraria (male):

Andrena cineraria (male)

Male Andrena sp. are very difficult to identify, but this one seems fairly safe, due to the ash-grey hair on the thorax. These have come to the end of their season, now.

There seems to have been a sudden hatch of Helophilus pendulus: I saw dozens today:

The hoverfly Helophilus pendulus (male)
Note that Helophilus sp. are different from other hoverflies, in that the eyes of the males don't meet in the middle. There is, however, a small kink in the leading edge of the eye, which is missing in the female.

This 14-spot ladybird caught my eye:

14-spot Ladybird
These are much smaller than the more common 7-spot, being roughly the same size as a match-head.

Finally, most people will be unaware that Cleavers - variously known by other common names, usually involving the word 'sticky' - has flowers:

Flower of Cleavers
Cleavers is a member of the Gallium family, which have 4 pointed petals. You can see the hooked seeds just behind the minute flower.

Monday, 18 June 2012

Gap in the clouds

An unexpected gap in the clouds prompted me to visit our highest local point in search of orchids.

Northern Marsh Orchid is the first of our local Dactylorhiza orchids to open:

Northern Marsh Orchid
All of the Dactylorhiza orchids freely hybridise with each other in a fertile manner, so I always like to assign a percentage of the three local 'species' which appear in any specimen. The first specimen, above, is very close to the 'clean' specification, (short spike, dark flowers, clean edge to lip of flower) so it is mostly Northern Marsh orchid.

The next specimen is paler and has a slight tooth to the front edge of the lip, so I'll give it 90% Marsh and 10% Common:

Northern Marsh Orchid with signs of Common Spotted Orchid

This third specimen is clearly a hybrid with Common Spotted Orchid (tall spike, still paler flowers, visibly sharp tooth):

Northern Marsh Orchid x Common Spotted Orchid

I'm pretty sure that third one has some Heath Spotted Orchid in it too.

Interestingly enough, the hybrids tend to follow the flowering dates of their major partner: Northern Marsh Orchid is always around 3 weeks earlier than Common Spotted or Heath Spotted, with hybrids somewhere in between, so it's not only physical characteristics that are shared. My 'clean' Spotted orchids are only starting to make spikes now.

I was astonished to also find a Common Twayblade orchid in this location:

Common Twayblade

I strongly associate Common Twayblade with limestone, so the road in this area must have been fortified or built with limestone chips, since this location is in a strongly acidic heath area. We need to be alert to just how much our actions can affect populations of plants (and hence insects).

Staying with the theme of habitat alteration, this part of the heath has become overrun with False Salmonberry:

False Salmonberry

False Salmonberry is an american rubus species that was introduced in Northern Ireland to support game birds for shooting. I first saw it locally about 5 or 6 years ago as isolated specimens, but now it has covered acres of heath, eliminating native species as it spreads. It is clear that this is yet another highly mobile and invasive plant.

Bumblebees that are brighter than usual tend to be males, especially if they have yellow hair where black would be expected.

Male Bombus lucorum
The tuft of yellow hair on its 'nose' is a clear indicator, but the overall colouring (in association with the absence of pollen bags from the hind legs) leaves little doubt. The flower is Common Catsear.

The hoverfly Sericomyia silentis is an excellent wasp mimic:

Sericomyia silentis hoverfly
It's quite a common hoverfly, but I rarely see it in large numbers.

Wednesday, 6 June 2012


I held back some images of a sawfly that I photographed at Murvagh on Sunday to see if I could get an identification. I managed to get it successfully to Tenthredidae, but could get no closer than that. I have now had confirmation from Hungary that it is the grass-feeding Tenthredopsis nassata:

The sawfly Tenthredopsis nassata

The sawfly Tenthredopsis nassata
The sawfly Tenthredopsis nassata
Not the best photographs I have ever taken (all on manual focus, since it was flitting from one grass to another very quickly), but a very handsome beast nevertheless. 15mm long from nose to tail (and probably an egg-laying female, since you can just make out the 'saw' in the last photograph).

I also took time to update my Species Index, which now contains 1430 species, an increase of 29 since this date last year.

Tuesday, 5 June 2012

Trip to the seaside

On Sunday I joined up with the Donegal Butterfly Survey group at Murvagh, west Donegal. Murvagh is on limestone and has excellent coastal grassland and forested areas inland, with the occasional dune and also scarce foodplants, so there is a wide range of unusual butterflies to be found.

When I arrived I immediately saw half a dozen Small Heath butterflies. These are very flighty at this early part of their season, so decent shots are quite difficult:

Small Heath butterfly

A little further along we found Horseshoe Vetch:

Horseshoe Vetch

Horseshoe Vetch is the sole foodplant of the Small Blue butterfly - the smallest butterfly in Europe - so we started to look in sheltered areas behind the dunes:

Small blue butterfly
The wingspan of this specimen was roughly 15 - 17 mm.

Dingy Skippers were seen, although not by my group, so I didn't get a shot of those. I did, however, get a decent shot of the day-flying Burnet Companion moth, which can very easily be mistaken for Dingy Skipper, and is often found in the precise locations that Dingy Skippers prefer:

Burnet Companion moth

One of my favourite early summer flowers is Heath Speedwell, with its tall, thin, elegant spikes of pale mauve flowers. It never gets very tall, with the tallest spikes reaching perhaps 15 cm from ground level. The following shot, however is quite fantastic:

Heath Speedwell and Creeping Willow
The oval-leaved plant surrounding the Speedwell is Creeping Willow, which is actually shorter than the Speedwell, so this 12-15 cm. flower is actually towering above the tree tops!

Here's a shot of the Creeping Willow seeds being produced:

Creeping Willow seed production

Further along the route, we turned more towards the Atlantic and found an interesting mix of plants and insects. This is Marram - the grass that binds the dunes together:

And this is Lyme Grass, another dune associate:

Lyme Grass

Close to these we found Wild Pansy:

Wild Pansy
And Spiked Sedge (if you think grasses are tricky, try doing sedges):

Spiked Sedge

I also spotted the larva of Garden Tiger moth:

Larva of Garden Tiger moth

And the larva of Dark Green Fritillary (a wonderful and scarce butterfly):

Larva of Dark Green Fritillary

Mouse-ear Hawkweed is identified by its lemon-yellow petals which are squared off and the fuzzy oval leaves:
Mouse-ear Hawkweed
Back at the car park, I noticed a single Cinnabar Moth:
Cinnabar Moth
Cinnabars are entirely dependant on Ragwort for their survival.

Sunday, 3 June 2012

catching up (2)

In my last post I mentioned that the 7-spot Ladybird pupates with a series of very quick abdominal stretches. Today I managed to record that brief moment in a series of shots:

The rear end has been attached to the leaf, and the whole body is thrust violently backwards in an attempt to split the outer skin:

The larva then slowly returns to its resting position:

In these last two shots, you can clearly see that the skin has started to split along the yellow line:

I don't know how long the entire process takes, but this one was observed for perhaps 20 minutes without making much apparent progress.