Limestone

I live in an area of highly acid soil, so I'm always keen to visit limestone areas. Soil type largely governs which plants can be found in a particular area, and different plants support different insects, so I always expect to find something new or different on these trips. Lough Erne is also much closer to sea level, so it's probably 7-10 days earlier than my local area.

My local violet is the Common Dog Violet - Viola riviniana, but this area has both riviniana and Viola reichenbachiana. The most obvious differences are the narrower flower and more pointed leaves: 

Viola reichenbachiana

And the dark, straight spur behind the flower:

Viola reichenbachiana spur

Both violets were growing on a verge accompanied by Ground Ivy:

Ground Ivy

Bluebells were just starting to open:

And this Dock Leaf Beetle - Gastrophysa viridula - was either touring or lost: they are rarely seen far from Dock leaves.

I spotted my first Ichneumonid of the year. The size suggests that these will be looking for either large flies or small moths:

This flower is Cardamine pratensis, which is the main foodplant of the Orange Tip butterfly, but is also used by the Green-veined White:

The minute moth is Micropteryx calthella, which is associated almost exclusively with Buttercups in my area, but it clearly uses other nectar sources when they are available. I don't expect to see Micropteryx calthella for perhaps another 3 weeks on my patch (the buttercups aren't even in bud yet).

I was delighted to find a new hoverfly species on the same verge. This is Epistrophe eligans, one of the earlier species to emerge:

 Male Epistrophe eligans

Another plant that I only ever see on limestone is the Cuckoo Pint, a most wonderful member of the Arum family:

Cuckoo Pint

No matter where I find Holly, I always find its leaf miner, Phytomyza ilicis. I was always curious that only one species of miner lives in Holly leaves because it seems such a safe place for an insect to live. It turns out that Holly heals very quickly when damaged, and the plant considers the mine to be a wound. Phytomyza ilicis is the only miner that moves quickly enough to keep ahead of the healing process:

Phytomyza ilicis on Holly

Moth flies are a mysterious group of flies that run around on plant leaves like little planes trying to take off. The larvae live in cesspits, drains and compost heaps:

Moth Fly

Lough Erne is a large expanse of water, so I usually expect to find some water-based species.

Alder Fly larvae are aquatic, and I only ever find the adults near rivers, ponds or lakes. The Alder Fly Sialis lutaria has to be one of the least aptly named of all species. It isn't a fly (it has 4 wings and is related to lacewings) and it has no association with Alder:

Alder Fly Sialis lutaria

Talking of aquatic species, I spotted this Coot sitting on her nest:

Coot

A couple of fungi to finish.

Last year I found a rather rare fungal infection - Taphrina crataegi - on Hawthorn. The leaves are only just open, and this bush was already infected:

Taphrina crataegi on Hawthorn

This appears to be the first record for Northern Ireland.

April 23rd is St. George's day, and St. George's mushroom - Tricholoma gambosum - is traditionally found around this date:

St. George's mushroom - Tricholoma gambosum

The spores are minute, around 5 x 3 microns:

Drumboe plethora

Drumboe is an ancient woodland on the west bank of the river Finn, a very short distance away from the town centre. Despite its proximity to shops, schools, church and football ground, it is home to many scarce species: perhaps five or six of the species that I have discovered to exist in Ireland come from this site.

As I mentioned earlier, no time is wasted when new leaves emerge. Today's pictures are all leaf-based and tomorrow I'll show the flowers and insects I found on my visit.

Leaf-miners come from 4 families: beetles, flies, micromoths and wasps. The instant the new Beech leaves appear, the mines of the beetle Orchestes fagi can be found. The mines are very distinctive, initially mining a gallery from the leaf centre to the edge where a blotch is formed.

The above image shows two mines ready for pupation to take place only a few days after the leaves have unfurled. There are a few reasons for mines to be so quick:

• Multiple generations - speed is important if other generations are to follow before the leaves fall
• Soft leaves - fresh, young leaves will be easier to mine and digest than old, hard ones
• Parasite avoidance - the less time in the mine, the less time to be found

In the early stages, the Orchestes mine can easily be confused with Stigmella sp. micromoths, due to the single line of frass that runs down the centre of the mine, but the terminal blotch is distinctive:

Staying with Beech, this is an atypical specimen of the mine of the micromoth Stigmella tityrella. Haphazard or oddly-shaped mines are often a sign of parasitization - this mine is usually confined to run between two of the main leaf veins.

Honeysuckle leaves are host to a large number of flies and wasps. This appears to be a mine of the fly Aulagromyza hendeliana, based on the widely-dispersed frass drops:

Holly would seem to be an ideal leaf to build a home, but only one of our species mines it. Phytomyza ilicis:

Birch leaves are even more recent than Beech leaves, and yet this Incurvarea pectinea micromoth is already about to leave the leaf to pupate:

As I was examining other Birches for mines, I noticed these yellow/orange bumps on a few leaves of one specimen. They reminded me very much of the lumps made by Taphrina torquinetii on Alder, so I checked the reference and found Taphrina betulae, which is a very rarely-recorded fungus.

This should not be confused with the much more common Taphrina betulina which makes the very recognisable 'Witches broom'.

First Irish Record (told you Drumboe was good).

More on Holly

As Gill observed yesterday, the edges of the mine made by the mining fly Phytomyza ilicis on Holly leaves are currently very sharp:I spent a couple of years fretting over the problem that only one single species of insect mines Holly leaves. Holly must be a wonderful place to have a mine: hard leaves and sharp points are great protection. The answer to the dilemma is stranger than the solutions that readily come to mind. All leaves attempt to heal themselves, and Holly is no exception. Holly has a very hard exterior surface, and when it heals itself, it does so with great strength. That means that any insect close to the healing point would be liable to be squashed by the leaf surfaces. Phytomyza ilicis is the only miner that can move faster than the leaf heals, so that's why it's the only miner in Holly. At this time of year the sunlight is weak and the healing process is slow, so the edges of the mine are sharper than they are in summer.

Eagle-eyed observers will notice that this unfortunate individual hasn't made it. Even thick Holly leaves don't make you completely immune to the attentions of parasitic wasps.


And this is typical damage caused by the Vine Weevil - Otiorhynchus sulcatus .
Otiorhynchus sulcatus also feeds on Rhododendron and I expect you'll find similar damage on vine leaves, although I don't get to see too many of those in Donegal....