Saturday, 28 September 2013

More from Banagher Glen

When I'm looking at leaves for rusts and other fungi I often come across caterpillars of moths, especially at this time of year when larvae are fully-grown and are looking for somewhere to pupate and overwinter.

This larva of the Coxcomb Prominent moth adopted a defensive posture by throwing its head backwards, using its legs to make it look spiky.

Larva of the Coxcomb Prominent moth
Just as I was writing this, I spotted that this photograph shows an important feature to aid identifications. The larva has a number of ocelli - simple eyes - arranged in a curve. If there is any doubt about whether you are looking at a caterpillar or a sawfly larva, then this is an important distinction: the larvae of sawflies have only a single ocellus.

Ocelli of Coxcomb moth larva
Here's an old image of a sawfly larva, showing the single ocellus:

Sawfly larva showing single ocellus
(That image shows how things have moved on in eight years; I used to think my photos were good in those days!)

We found another larva on Birch:

Larva of  Light Emerald moth
Seems to be the Light Emerald moth, which overwinter as larvae.

New to my Species Index.

Leaf mines are also maturing at this time of year. This is the fly Phytomyza tussilaginis:
Mines of Phytomyza tussilaginis on Coltsfoot
New to my Species Index.

And another new species for me: 

Mines of the micromoth Phyllonorycter nicellii on Hazel
New to my Species Index.

Fungal foray to Banagher Glen

Banagher Glen is a mature woodland on sloping river banks. Deep shade and high humidity, along with mature broadleaf trees, make an ideal environment for fungi: the first specimens were immediately visible at the edge of the car park.

Lactarius torminosus was the first of many species of Lactarius found on the day. It is a Birch associate and is easily identified by the woolly cap:

Lactarius torminosus
We also found the very early stages of Clavaria acuta, at about 2 cm. tall:

Clavaria acuta, just emerging
The majority of the mature trees were Oak, Beech and Hazel, all of which have their own Lactarius species. I found the Hazel associate Lactarius pyrogalus which, as its name suggests, has very fiery milk:

Lactarius pyrogalus
New to my Species Index.

When I first saw this little orange mushroom, my first reaction was 'Waxcap':

Lactarius aurantiacus
But on flipping it over, the close gills and milk revealed that it was clearly a tiny (20 mm.) Lactarius.

New to my Species Index.

We also found many huge specimens of  Lactarius chrysorrheus under Oak:

Lactarius vellerus
New to my Species Index.

Another new species for me was Russula betularum, under Birch:

Russula betularum
New to my Species Index.

Because I'm always searching for fungal rusts, I often find other species on leaves. These are the leaf galls of the asexual stage of Neuroterus quercusbaccarum on Oak:

Galls of  Neuroterus quercusbaccarum on Oak
I also found this specimen of the Dung Beetle Geotrupes stercorarius:

Dung Beetle - Geotrupes stercorarius

Tomorrow I'll show the larvae and leaf miners that I found.

Thursday, 19 September 2013

More fungi

I have the opportunity to attend a fungal foray on Saturday, so I thought I would check out my local area to see if there were many fungi around. Whilst I didn't find anything unusual, the sheer number of specimens was astonishing.  These two shots might give some impression of what I found:

Fungi on woodland floor

Fungi on woodland floor
Most of the specimens in this area were Russula mairei (Beechwood Sickener) or Lactarius blennius, although the second photo shows a cluster of Mycenas at the centre.

I also found a single specimen of the Honey Fungus, Armillaria mellea:

Honey Fungus - Armillaria mellea

And a few Deceivers - Laccaria laccata:

Deceiver - Laccaria laccata
The Deceiver gets its name from the fact that it changes colour and shape as it matures, and can often resemble other species. It smells very much like the yeast used for making bread.

Here is a mature specimen:

Mature Deceiver

Helvella crispa is just appearing through the grass. It is always contorted and irregular:

Helvella crispa
I find Mycenas quite tricky, probably because I don't (yet) have a key to them:

Mycena cf. amicta
A fungal foray on Saturday certainly seems worthwhile.

Sunday, 15 September 2013

It's a funny old world

Yesterday I was casting a satisfied look over my vegetable plot - deciding what to have for dinner - when I saw a good, clean specimen of the Silver Y moth, and dashed inside to get my camera:

Silver-Y moth

Silver Y moths are usually immigrant, although some breeding is known. Survival over winter is unlikely, so most specimens will be found after a warm southerly wind, just like we had on Tuesday and Wednesday.

Since I had my camera in hand, I had a quick look at the hoverflies and bumblebees that were busy pollinating my courgettes and I spotted movement on my broccoli leaves:

The Ichneumon wasp Hepiopelmus variegatorius
A quick glance told me that she was an Ichneumonid of some kind, and it was clear that she was investigating the larvae of the Large White butterfly under the leaves. She was moving at an incredible speed, scurrying over and under leaves, often disappearing completely from view.

The Ichneumon wasp Hepiopelmus variegatorius
I rattled off perhaps 50 shots, trying to catch her as she paused at the edge of a leaf long enough to get a decent image. Her antennae were rarely still as she constantly sampled the air and decided whether or not to look under a particular leaf:

The Ichneumon wasp Hepiopelmus variegatorius
From time to time I managed to get a glimpse of her through various holes in the leaves. You can just make her out in this shot:

The Ichneumon wasp Hepiopelmus variegatorius under a leaf

I 'massaged' that shot in the photo editing program and found that she was getting very close to the larvae (which can just be seen at the top of this shot):

The Ichneumon wasp Hepiopelmus variegatorius investigating a larva of the Large White butterfly

My next task was to try to get an identification, and I first turned to a list of known parasitoids of the Large White butterfly. The Large White has been very extensively studied, since it is seen as a pest species for crops, and methods of control are always being sought. A fairly quick search (perhaps 2 hours) revealed nothing like a match, so I went to the references (the most recent one is 1960!) and searched for identification via that unusual crescent on her thorax. Still no luck.

I decided to 'phone a friend' and NHM London in the guise of Gavin Broad came up with Hepiopelmus variegatorius, which fortunately is one of the few Ichneumons that can be accurately identified from a photograph. These are known to parasitise the larvae of Spilosoma sp. (Ermine Moths), so the Large White larvae were safe in this particular instance.

Back to the reference, to find that Hepiopelmus variegatus is described as rare in the UK, and a quick search of the Irish national database revealed no previous records for Ireland. So this seems to be a first Irish record (confirmed 16/09/2013).

If I hadn't seen the Silver Y, then I wouldn't have had my camera to hand, and that record would still not exist.

1508 Species, now.

Thursday, 12 September 2013

A major milestone

I decided to update my Species Index with the sightings from 2013, since I calculated that I might be close to 1500 species. It turns out that I have now amassed a grand total of 1507 species on my websites, with number 1500 going to the Destroying Angel on August 27th.

The total at the end of 2012 was 1461, so I have added 46 species so far this year. Part of this number is due to the fact that I have been invited to a number of Bioblitzes this year, and I always find something new when I go to a new location, especially if the new location is on limestone. But a few are simply species that I have previously overlooked or not had the opportunity to take a photograph. The Silver-washed Fritillary from August 28th is an example of the later category.

Here's the annual graph so far:

Species 1507 is the sawfly Heterarthus aceris:

Mine of the sawfly Heterarthus aceris
This is a common miner of Sycamore (although I certainly haven't seen it before, and there are (were!) no records in the national biodiversity database). The mine is located at the bottom right of the image. The black dots on the leaf belong to the fungus Rhytisma acerinum - Sycamore Tar Spot.

Tuesday, 10 September 2013

An assorted bag

We are clearly sinking down into autumn: temperatures are dropping and there are signs of an annual wind-down wherever we look. One of the most obvious signs is the large number of caterpillars that can be seen wandering out in the open, rather than feeding in hidden places. This is due to them seeking a pupation place where they will make a cocoon that they will remain in during the winter before emerging as adults next year. This is the normal overwintering strategy for most of our insects, since it makes sense to have a cosy wrapper during the coldest part of the year. That is not to say that this is the only strategy: some species overwinter as eggs, others as adults - some hibernating, others being active during only this part of the year. Different strategies have different benefits: those species that are active during the winter must put up with the colder temperatures, but there is less competition for food and there are fewer predators around.

Recent caterpillar sightings include:

The Small Tortoiseshell butterfly, on a patch of nettles which I allow to grow near the chicken run:

Larva of Small Tortoiseshell butterfly
And the Flame Shoulder moth, which feeds on Dock and Dandelion:

Larva of Flame Shoulder moth
It should be noted that there are two distinctly different colour versions of this larva: the other version is brown.

This is also a good time to have a look at lichens: some of the vegetation and leaves that hide them are beginning to die back. This is the rather scarce lichen, Pannaria rubiginosa:

Pannaria rubiginosa on Oak
Pannaria rubiginosa is an indicator of extremely clean air, growing only in the west of the country. It's said to grow on various deciduous trees, but I have only ever found it on Oak. The red objects are the purely fungal fruit-bodies which eject spores for wind-dispersal, and the coppery filaments at the top and bottom of the image are the very common liverwort Frullania tamarisci. F. tamarisci is, again, a mainly western species.

I had an idea that the sunny spell at the weekend might be one of the last for a while, so I dashed out to see what I could see. There were many hoverflies still flying, and I got a decent shot of Helophilus pendulus, along with an unidentified muscid:

The hoverfly Helophilus pendulus (top)
And also a late shot of the solitary bee Halictus rubicundus:

The solitary bee Halictus rubicundus
I should actually use the term 'solitary bee' with some restraint in this instance: Halictus rubicundus is usually solitary, with each female making her own tunnel for her own eggs, but there is evidence that this bee can actually operate in a pseudo-social manner, with some females acting as pseudo-queens in aggregated colonies. This behaviour might show an evolutionary link between solitary bees and social bees, or perhaps we're seeing a change in behaviour from solitary to social in a particular species (or maybe even the reverse!)

New to my Species Index.

I found a snippet of information last week that put a completely new slant on how I understand the relationship between host and parasite/predator. In the normal circumstance, a predator or parasite cannot be present if its host is not present: the host must always precede the predator. This is simply because the predator must feed, and cannot exist in the absence of its food source. So the normal course of events is that a species arrives, perhaps through warming, or perhaps through human intervention, and survives in the absence of its parasite(s). That's one reason why invasive plants can survive so successfully: their native parasites and predators have not yet arrived. Eventually, through accident or, again, through human intervention, parasites and predators turn up and begin to keep numbers in check: a few weeks ago I posted images of a new leaf-miner on Himalayan Balsam. Another new(ish) leafminer - Cameraria ohridella - that mines Horse Chestnut leaves arrived in England from the continent a few years ago, and has been spreading northwards at quite a rate. The damage to infected trees can be quite severe, and it seemed that unless its native parasite(s) turned up to keep a check on its numbers, some of our trees might be threatened. But this year it was noticed that infections were less severe than in previous years. Despite extensive checking, however, no specimens of any specific parasite could be found. Then we began to get reports that people had seen Blue Tits and Great Tits feeding on the larvae and pupae of the miner: it seems that they have learned about this new food source that they had previously been ignoring. This adds a new dimension to my understanding of parasite/predator/host interactions: in cases where the predator is not an obligate feeder on a host (Tits can eat many other insects), the predator can pre-exist the host and only becomes a predator once it realises that it can be a predator of the host. Fascinating.

Monday, 2 September 2013

September already

September is good time to look for leaf mines: most of them are now fully-developed, and the larvae have mostly pupated.

The mine of the micromoth Heliozela resplendella is one of the most interesting examples:
Mine of Heliozela resplendella on Alder

The miner starts around point C, on the central vein. It then proceeds via a side vein to point B, where it leaves the vein and mines the soft tissue to point A, where it enters another side vein which it mines back towards the central vein at point E. Having reached the central vein, the miner continues to mine it until it reaches point D, at the petiole. It then reverses direction and mines the central vein back to point E, where it enters a side vein. It then makes a very short blotch along that vein before cutting an oval piece of leaf at F. It then descends to the ground, and uses the oval piece of leaf as a pupation wrapper.

This preference for the woody vein material over the soft leaf tissue is a reversal of the usual mining preferences, where soft tissue is eaten, but veins are used for navigation, rather than food.

It should be noted that in some instances of this miner the journey via the soft tissue is omitted: the only externally-visible sign of the mine in those instances is the oval cutout in the leaf.

A single specimen of the July High-flyer came to light:

July High-flyer
These can be separated from the Autumn Green Carpet by the round shoulders and the black diagonal slashes at the rear corner of the wings. Can you see the black slashes? Nope, neither can I: they're worn off.