Thursday, 27 June 2013

High Heath

The Green-veined White butterfly has two generations per year. Unusually, the two generations are quite close, with some slight degree of overlap. Summer generation specimens are more strongly marked, with the black markings being darker and sharper than those of the spring generation.

 This pristine specimen is a female:

Female Green-veined White, summer generation
Given the lateness of the year, this is a rather early specimen for the second generation.

I have found the same, strange, earliness in the bumblebees this year. Queens emerged rather late, and nests were subsequently late, with workers not appearing until a few weeks ago. There is usually quite a delay until the new queens and males are ejected, but I have been seeing new queens and males for a couple of weeks now: much earlier than usual. It seems that some species are actually accelerating this year, despite the slow start, and are now ahead of normal schedule, rather than maintaining the 'lateness'.

Male bumblebees are ejected from the nest to fend for themselves, mainly because they do no work and would be an overhead on the nest. They are quite easy to identify, both in behaviour and appearance: they tend to crawl slowly over flowerheads in contrast with the workers which gather pollen almost frantically. They are also rounder, more colourful and have longer hair, giving them a 'fuzzy' appearance:

Male Bumblebee on Common Catsear
Any bumblebee with yellow hair on its face is likely to be a male, although not all males show this feature:
Male Bumblebee showing yellow hairs on the face
It isn't possible to identify these males to species without internal examination, but given the location, I'd go for Bombus lucorum s-s.

The hoverfly Helophilus pendulus is very numerous at the moment, with sightings on every excursion and location.

The hoverfly Helophilus pendulus

But I still examine every specimen, since I know that the much more local Helophilus hybridus can occasionally be found:

The hoverfly Helophilus hybridus
These rarely fly more than a few hundred metres from the boggy areas that contain Bulrush - the foodplant of their larvae. Identification relies on the differences between the markings on the abdomen. I might see only one or two of these each year.

The hoverfly Platycheirus scutatus was split into 4 species quite recently. Irish specimens appear to be the original Platycheirus scutatus s-s.

Platycheirus scutatus, female

Platycheirus scutatus, female
The larvae of these feed on aphids on low-growing vegetation.

Digger wasps can often be mistaken for hoverflies due to the oval yellow markings on the abdomen, the large head and the apparently short antennae: all features of hoverflies. These are predators on hoverflies, killing them and taking them back to the nest to feed their larvae:

Ectemnius continuus
Their appearance enables them to mix with hoverflies and approach them without disturbing them: I have often seen hoverflies and Ectemnius wasps feeding on the same flowerheads.

Hoverflies mimic the colour patterns of wasps and bees with greater or lesser accuracy. This enables them to inherit the protection that the colour patterns give to bees and wasps: birds know to avoid yellow and black -  nature's danger signal. So Ectemnius wasps are imitating hoverflies that are imitating wasps.

Staying with mimicry, Volucella bombylans is a hoverfly that mimics bumblebees (and lays its eggs in bumblebee nests):

The bumblebee-mimicking hoverfly Volucella bombylans
Volucella bombylans comes in at least three colour versions, each mimicking different bumblebees. I would dearly like to know if the different versions choose appropriate bumblebee hosts to rear their young.

Sawflies are very difficult to identify to species without a specimen, a microscope and a key. I have recently obtained a copy of the (55 year-old!) key and have identified this specimen as Tenthredo mesomelas:

The sawfly Tenthredo mesomelas
In an effort to understand these adults and larvae, I am participating in an online effort to gather together images of both adults and larvae of all sawfly species together for the first time.

When I was down taking photographs of orchids (see here), this micromoth flew over my head and landed on the Luzula upside-down, as so often happens.

The micromoth Glyphipterix thrassonella
The larvae of Glyphipterix thrassonella feed on Juncus rushes, which were in profusion. This is the first time I have seen this species since 2005.

Meadowsweet must be a very nutritious plant: there are many miners, micromoths and fungi which use it as a host. This is the fungal rust Triphragmium ulmariae, which is specific to Meadowsweet:
Triphragmium ulmariae on Meadowsweet
Note that the fungus has distorted the stem of the plant in order to maximise its surface area and therefore increase its chance of spore-dispersal.

And this is the mine of  Agromyza filipendulae on the same plant:

Unusually-shaped mine of Agromyza filipendulae on Meadowsweet

Note that this particular mine is atypical: it should have continued spreading to the left, but for some reason it has turned back at the fourth vein. Perhaps it was parasitised.

Monday, 24 June 2013

Spotted Orchids (better late than never)

I saw a few spotted orchids during a rainy walk yesterday, so I thought I would try to get a representative sample while the lowest flowers were just opening. In my opinion, this is when an orchid plant looks best: once the higher flowers are open, the lower ones can look very untidy and spoil the overall look. As usual, I will give my assessment of what species are present in each specimen, with rationale. The three 'species' photographed are Common Spotted Orchid (CSO), Heath Spotted Orchid (HSO) and Northern Marsh orchid (NMO). 

Characteristics used:

CSO has white to pink flowers with a clearly pointed centre lip and pointed outer lips
HSO has white to pink flowers with a continuous frilled lip and only a small point, if present
NMO has purple flowers with a smooth continuous lip. Flowerhead usually squat. Flowers earlier than the previous two species.

This first one looks to be pretty well 50/50 CSO/HSO due to the pale colour and the fringed outer lips with a spiked centre lip.

Common Spotted Orchid x Heath Spotted Orchid

This specimen looks to be pure CSO due to the three-pointed lip:

Common Spotted Orchid

This appears to have all three parents, with a central tooth, frilled outer lip and darker colour:

Hybrid Spotted Orchid
This appears to be mostly NMO, due to the darker colour and continuous, unfrilled, toothless lip, but the upper flowers are tending to pale and the spike is quite tall:

Hybrid Spotted Orchid
This paler specimen is mostly CSO, with a touch of HSO due to the slightly frilled/rounded outer lip:
This looks to be a very clean NMO, due to the short spike, already fully-open flowers, darker colour and continuous lip, but there is a tiny hint of frilling, so we have to consider some HSO:
A good, clean CSO (triple teeth with almost no frilling):

Common Spotted Orchid
This is clearly part CSO (long central tooth) and HSO (frilled outer lips):
Note that the central flower in the above spike is still rotating clockwise into its 'upright' position.

This last shot shows, I think, a triple hybrid between HSO, CSO and NMO. There is a clear frill round the lip, there is a central tooth and the colour is quite dark with a shorter spike:

Triple hybrid Spotted Orchid
I cropped that last shot to include the Heath Woodrush on the left.

Please note: the differentiation between Dactylorhiza orchids is contentious at best and uncertain at worst. I also believe that they tend to vary according to micro-habitat, with specimens with wet feet tending towards HSO and those with dry feet tending towards CSO. The variability in your area might well be different.

Sunday, 23 June 2013

Ballyraine National School

Last week I gave a wildlife talk to pupils from Ballyraine NS in Letterkenny. After that, we went out for a walk around the school grounds to see what we could find and photograph. This page shows some of the interesting finds from that survey, and the text is intended for a school audience.

The first location we visited was the Butterfly Garden. This is packed full of flowers that attract butterflies and other insects.

Our first find was the hoverfly Helophilus pendulus. Hoverflies are important for pollinating flowers, trees and fruit.

The hoverfly Helophilus pendulus

Next we found a 2-spot Ladybird. These are much smaller than the more common 7-spot Ladybird, which we also saw.

2-spot Ladybird
Another part of the Butterfly garden contained Lupins, and these attracted workers of the White-tailed Bumblebee:

White-tailed Bumblebee
You can see the bright orange Lupin pollen in the pollen baskets on her legs. This pollen will be taken back to the nest to feed the growing grubs.

At first, I thought this was a little Sepsid Fly, but some research reveals that it's the much rarer Rivellia syngenesiae, which I haven't seen before (and there are no previous records in the National database!)

Rivellia syngenesiae
That little fly is only 3-4mm. long!

We then moved to the area of woodland at the edge of the School grounds, where we found a number of leaf-mining species. Leaf-miners live inside leaves, eating the middle layers of the leaf where they are protected from predators such as birds and other insects.

The mine of Phytomyza ranunculi on Creeping Buttercup

We also found the mine of Caloptilia syringella, which mines Lilac, Privet and Ash:
Mine of Caloptilia syringella on Lilac
Caloptilia syringella is the only leaf-miner on Ash, so it is fortunate that they also use other plants which will help them to survive if the Ash trees die in the next few years.

Most miners make their own mine, but some species make communal mines. This photograph shows two larvae of the leaf-mining fly Pegomya solennis on Dock:

Larvae of Pegomya solennis on Dock (heads to the left)

Some other species of flies also use leaves, but in a different way: Leaf galls are growths created by flies (and sometimes other insects) to make a shelter to live inside and feed on.

This is a Pontania gall on a Willow leaf:

Pontania leaf gall on a Willow leaf

And these galls are made by another species - Eriophyes sorbi - which is also new to me:

Eriophyes sorbi galls on Rowan

In the same location, we found this tiny fly:

Tiny Fly with iridescent wings

And also this Dung Fly, which was waiting to pounce on any passing insect:
Dung fly poised to leap out on any unsuspecting prey

Towards the end of the walk we found some Foxgloves:
Foxglove, a highly poisonous plant
And a single Herb Robert flower framed by the fencing:

Herb Robert
I have submitted records of all these species to the National Biodiversity Database which will help to build up a record of where our species are located.

The school website can be found here.

Thursday, 20 June 2013

Mixed weather

We're having sunny spells, showers and heavy rain in waves these days. Still, it beats the perma-rain of the last two years.

I really liked this shot of the 7-spot Ladybird. These are voracious predators of aphids, and if you look closely under the left-hand side of the leaf, you can see the antennae of its dinner.

"It's behind you"
This young Rabbit has taken up residence in the ancient Hawthorn hedge at the bottom of my garden: it seems to like being near the hens. I'm happy with all of that, but I'm rather keen that it doesn't find my vegetable plot, which is perhaps another 10m on the other side of the coop.
Young Rabbit
New to my Species Index.

Most beetles have wings which are folded away under the two elytra, which themselves are actually modified wings. The wings can be inflated at incredible speed, and you have to be very quick to catch the unfolding process taking place. I watched this Click Beetle flying from plant to plant and managed to anticipate the moment of launch:

Click Beetle preparing to fly

Leucozona lucorum is a hoverfly that is around in great numbers at the moment. They are very flighty (and will be until the mating season is over), so shots have to be taken very quickly:

The hoverfly Leucozona lucorum

Orange Tip butterflies were very late this year - at least 4 weeks and maybe 6 weeks later than I would expect. Their season is timed to match their foodplant (Cardamine pratensis in this area), and once the eggs have been laid, the adults fade away over the next week or two and won't be seen until May next year, when the next generation hatches.
Male Orange Tip butterfly
Fortunately, I have found a few larvae feeding on the seedpods:
Orange Tip larva on Cardamine seedpods

This is a strange visitor to our area. Salad Burnet - Sanguisorba minor - is a lime-loving plant, and we are are on strongly acidic soil. A few years ago, I limed part of my vegetable plot and I think this came in with a salad mix that I sowed around the same time.

Salad Burnet - Sanguisorba minor
New to my Species Index (although I think it's a bit of a cheat).

For a few years, I have been following the fortunes of a patch of pure white Bush Vetch that I found near the high heath. Many sports don't last long, but this patch is increasing in size and seems to have no problems attracting bees to pollinate it.

White version of Bush Vetch
I have read that a few plant species with blue flowers can occasionally throw pure white sports, mainly in the West. I suppose the ultraviolet parts of the flower still work, even though it's purest white to our eyes.

Sunday, 2 June 2013

Another bioblitz

I was invited to another bioblitz on Saturday, this time at Lissan House, near Cookstown. The weather looked pretty dismal when I arrived, but eventually the rain stopped, clouds cleared and we had bright sunshine for a few busy hours. I always enjoy a trip to new locations, since I usually find some species which are new to me.

I was again 'doing' hoverflies, miners and microfungi, but I always reserve the right to make a detour if something attracts my attention. The first plant to catch my eye was Common Bistort, down by the river:

Common Bistort
 This has large, soft leaves and I soon spotted its fungal rust Puccinia bistortae:

The fungal rust Puccinia bistorta
The alternate hosts for Puccinia bistortae are Angelica and Pignut, both of which I found nearby. Rusts usually alternate between two species, but this choice of two completely unrelated alternate hosts is new to me. No doubt there will be others....

Both the Bistort and its rust are new to my species list.

The next species I found also shouted "NEW" to me:

Unusual red form of Gymnocheta viridis
The black spines immediately identify it as one of the Tachinid flies, which are parasitic on moth and butterfly larvae, and although I have seen quite a few Tachinid species, I have never seen a red one before. I rattled it off for expert opinion, and am told that Gymnocheta viridis (which I have shown before a number of times: for example here) can sometimes turn red - due to exposure to sunlight - as it ages. That's not the kind of information you'll find in any books.

I then joined up with two more bioblitzers and we headed for a wildflower meadow, where we found dozens  (hundreds?) of butterflies, including Green-veined White, Large White and Orange Tip all chasing each other around in the fresh sun: a wonderful sight.

Since the Buttercups (in this case both Creeping and Meadow) have just opened, all their associates are immediately in evidence. This shot shows the tiny Hydrothassa marginella beetle, which I have never found away from a buttercup flower:

The beetle Hydrothassa marginella

I also spotted this longhorn beetle, Rhagium bifasciatum:

The longhorn beetle Rhagium bifasciatum

And a single specimen of the Small Copper butterfly, which caused a bit of a stir:

Small Copper butterfly
En route between meadows, we passed through a heavily wooded area, and spotted a dead Birch with three specimens of the Birch polypore bracket fungus Piptoporus betulinum, which I am astonished to find is not on my species list, although I have seen it many times before:

The bracket fungus Piptoporus betulinum
One of these specimens was dissected and a number of small beetles were found inside. Bracket fungi are very long-lasting, and are the perfect habitat for many insects, especially beetles.

New to my species list, for some odd reason.

We also found a couple of ascomycetes on dead Beech:

First a species which glories in the name of Biscoingiauxia nummularia:

Biscoingiauxia nummularia
I am told this is the furthest north that Biscoingiauxia nummularia can be found in Ireland. Now THAT's a challenge......;)

And beside it, Quaternaria quaternata:

Quaternaria quaternata

Both of the previous species are unique to dead Beech, and are both new to my species list.

So that's 5 new species for my list: not bad for a few hours work.

Another great day out, and more new contacts and like-minded friends. These bioblitzes are brilliant.