Pollinators

This week I was giving a talk as part of an international conference about pollinators. If you mention pollinators most people immediately think of bees, and bees are certainly extremely important plant pollinators. Other groups of insects, however, are also important in the pollination process, and I was covering hoverflies. I spoke to the other speakers on non-bee pollination (one discussing beetles, another covering butterflies and moths and a third talking about ants), and it was clear that there is actually very little scientific literature out there that discusses and compares the contributions made by these other groups.

I made the case that since there are more species of hoverfly than bee in Ireland, and there are clearly more hoverfly specimens than bee specimens, that hoverflies are obviously an important player in plant reproduction. Yes, bees are 'busier', visiting more plants per minute than a hoverfly, but bees also take pollen back to their nests to feed their young. This takes pollen OUT of the plant reproduction process, rather than assisting. Further, there are bees that short-circuit the nectar-taking process by cutting into the rear of flowers, thereby bypassing the pollen-gathering part of the arrangement. This is theft.

I then went on to discuss the lifecycle of hoverflies, and pointed out that some species of hoverfly lay their eggs in bee nests. Their larvae eat the detritus in the nests, keeping them healthier and more productive. So hoverflies are assisting some bees. Lastly, I discussed the fact that some hoverfly larvae feed exclusively on aphids: yet another beneficial aspect to this group.

The beetle and ant speakers struggled to find any evidence of plant pollination other than incidental or accidental transfers as they moved from plant to plant. The one saving grace as far as ants are concerned is that they 'farm' aphids, thereby providing a food source for the hoverfly larvae!

After the talk we went on a tour around the excellent conference site (Oxford Island at Lough Neagh) and I took the camera with me.

The following shots show how things are progressing with the new 70D camera.

This is the original shot (reduced in size!) of the hoverfly Eristalis pertinax:

Eristalis pertinax - original full-frame shot

This is the same image cropped to show the whole insect:

Original image cropped to the insect 

And this is a crop to just the wing veins:

Crop showing just the wing veins

These three images were all taken from the same original. This camera continues to astound me with its performance.

The image is also instructive in another way: In the field I initially identified this as Eristalis pertinax. But when I blew it up on the computer I noticed the dark wing shade and the yellow margins to the abdominal tergites. The only species on my patch that looks like that is Eristalis horticola, so I changed my identification without any further thought.

I showed the images around and was informed that this was indeed Eristalis pertinax, and that occasionally it can have a dark wing shade! Lesson learned: although I can safely identify my local set of species, I need to take into account variations that might occur outside my immediate geographical area.

Someone found this mine on Wood Avens and brought it for me to look at:

Mine of Stigmella aurella on Geum

I immediately recognised this as a Stigmella mine (central frass in a corridor mine), but didn't know which species of Stigmella mines Geum. So I took the images and went back to the office to check the internet. Turns out it's the very common Stigmella aurella, which I have often shown on Bramble. Bramble and Geum are both members of the Rosaceae, so they're quite closely related. It's nice to get confirmation from details like this that the plant taxonomists were right!

Finally, I found a few pristine specimens of the Parasol Mushroom, Lepiota procera:

Lepiota procera - Parasol Mushroom

I think I'll have a fungal foray to Ards on Sunday.

Surprises

In my last post, I showed the buds of Barren Strawberry. The flowers have now opened:

Barren Strawberry

As I was taking the shot, my eye was attracted to a flash of purple to my right and I saw the first flowers of Germander Speedwell:

Germander Speedwell

The second surprise for today was the sudden appearance of the Scarlet Elf Cap - Sarcoscypha austriaca var. austriaca:

Scarlet Elf Cap

This isn't a scarce species in damp woodland at this time of year, but it's the first time I have seen it on this patch.

Third surprise was this little Sepsid fly:

Sepsis punctum

Sepsids are known as 'Semaphore flies' due to their habit of waving their spotted wingtips up and down in some sort of signalling ritual. This one was busy cleaning itself, so I'm pretty sure it had just emerged, triggered by the warm sunshine. New identification.

Next surprise was the Cow Parsley beginning to open. I don't normally expect to see that until April.

Cow Parsley just opening

When looking at flowers, I always check for miners, and sure enough, the usual suspect was present and correct:

The mine of Phytomyza chaerophylli on Cow Parsley

You can just make out the shiny black pupa at the top of the mine.

Staying with miners, I noticed this odd mine of the micromoth Stigmella aurella on Bramble:

Badly-formed mine of Stigmella aurella

This one made its first wrong turn when it met the second vein and turned back on itself, and compounded this with another wrong turn as it returned to the first vein. It has now gone into a decreasing spiral and has run out of food. That's one genetic experiment that won't be passed on to future generations.

The frogs in the ditch have finally spawned:

Frogs (left) and spawn

This is approximately two weeks later than I would normally expect, although the adults have been around for at least 3 weeks.

My search for species for the 1k square challenge has now reached just over 200 species in a week, with very few new additions to the square apart from the Sarcoscypha and the Sepsid.

The signs are there

We have rain forecast for the next few days, so I took the opportunity to see what signs of spring I could find.

7-Spot Ladybirds hibernate as adults, so in theory they can be seen at any month of the year if the weather is warm enough. But I like to think that the first sighting of the year is a sign of things to come:

7 Spot Ladybird

Many plants are still in their purely vegetative state, but quite a few are making flower buds or new growth. I always consider Barren Strawberry to be the first true flowering plant in each year. True, Celandines will always flower first, but since they can flower any time from November onwards, the Barren Strawberry is my 'first flower' in any given year:

Barren Strawberry flower bud

The plant at top right of that shot is Germander Speedwell which had a very good year last year:

Germander Speedwell

The lowest stem in that shot shows the diagnostic paired lines of hairs that run along the stem.

Bush Vetch is also pushing through the dead fronds of last year's Male Fern:

Bush Vetch

It will be another 4 months before Slender St. John's Wort is in flower, but already the new growth is forming:

Slender St. John's Wort

I cropped this shot of Opposite-leaved Golden Saxifrage to show the rear wall of the ditch covered in liverworts and mosses:

Opposite-leaved Golden Saxifrage with liverworts and mosses

The main liverwort is Conocephalum conicum ('Snakeskin Liverwort') and the tiny moss is Plagiomnium undulatum.

A few years ago, one of the few local areas to have wild Reedmace was excavated to see if it would be suitable for building a house (it isn't!). Most of the Reedmace disappeared, but some has now made a recovery:

Reedmace - Typha latifolia

Typha is the sole host family for many insects, including some moths and hoverflies. I examined quite a few specimens of the Reedmace for any signs of those species, but none were found. I wonder how long it will take for them to return (if they ever do).

No time is ever wasted in nature: the leaves of Lesser Celandine are hardly full-grown and already the fungal rust Puccinia ranunculi has taken hold.

Puccinia ranunculi on Lesser Celandine

Last year there seemed to be a very wide-ranging absence of fresh mines of the micromoth Stigmella aurella from its main foodplant, Bramble, and I certainly found very few.  So it's good to see a good number of fresh mines (fresh mines are white, whereas old mines from previous years are brown) on the host plant this year:

Mines of the micromoth Stigmella aurella

There are 4 mines on that leaf, all of which appear to have grown to full size. I'm always entertained by the way the mines progress without falling out of the edge of the leaf and also how they seem to detect other mines and take avoiding action before they intersect them (or their own!), especially when older.

Drumboe Wood

Whilst Ards is a rare, ancient, coastal forest, Drumboe is perhaps even more unusual: it's an old woodland in a central urban setting. Shops, main road, schools, church, hotels and a GAA football ground are no further than 100 m. distant and thousands of people pass it every day with no idea of the rich biodiversity just a stones-throw away.

This shot show shows the River Finn with Drumboe to the left:

River Finn: Drumboe to the left and Ballybofey to the right

The woodland is maintained by Coillte, and the management plan shows a strategy of at least partial replacement of Spruce with native broadleaf trees when the conifers are harvested.

I only had time for a quick visit, but I managed to find a few interesting specimens:

Scleroderma citrinum is a common earthball with a surface criss-crossed with sharp grooves which will eventually act as fault lines for the skin to split along when the fungus is ready to disperse its spores. This specimen is about the size of a golf ball:

The earthball Scleroderma citrinum

Phycopeltis arundinacea is an algal infection that looks very much like a fungal rust:

Phycopeltis arundinacea on Ivy

I find it mostly on Ivy, but I have also found it on other plants with shiny leaves, most often Rhododendron.

Lycoperdon pyriforme is one of the more common puffballs in this area. They can often be seen to form long rows, seemingly growing on the ground, but they are actually following the line made by buried dead wood:

Lycoperdon pyriforme

Leafy liverworts are very often mistaken for mosses, but their habit and form are very different. I spotted this specimen (sample shown about 8 cm across) and suspected it was something I hadn't seen before:

Liverwort growing with moss in damp bank

I took a sample back to the microscope and saw that it has two tiers of leaves (large ones on top and small ones below). The presence of underleaves is unique to liverworts, although not all species have them. This microscope shot of a single frond (12 mm long) shows the view from underneath:

Calypogeia neesiana

It keys out in a couple of keys to Calypogeia neesiana, which is new to my Species list.

This shot shows two mines of the micromoth Stigmella aurella on Bramble:

Two mines of the micromoth Stigmella aurella on Bramble

These mines usually grow quite long, so they are usually found at a maximum of one per leaf; perhaps the second egg was laid by a different female. Each mine progresses quite normally from its starting point, but they eventually meet just left of centre. The mines then become very confused, with much to-ing and fro-ing in the left part of the leaf before they separate and at least one has matured safely (top left). I'm not sure what happened to the second, though.

Bumblebees have historically been summer-nesting species, with the queen making her nest from March onwards. But in recent years, southern queens of Bombus terrestris - the Buff-tailed Bumblebee - have been observed gathering pollen in autumn and they have successfully created winter nests. Presumably we have reached a critical temperature due to warming, since winter nests are common on the continent.

Yesterday I spotted a queen gathering pollen from the Lavatera in my garden:

Queen Bombus terrestris gathering pollen 29/10/2012

This is quite a surprise. I knew of southern specimens trying to establish a nest at this time, but it's not something I would have expected to see this far north. Granted, we did have a few days of sun, but I tend to think that she isn't confused and has decided that it's worth a try this year. So here is a rash prediction, based on a single queen bumblebee: "Mild winter ahead".

Full steam ahead

After a wet early start, St. Patrick's day eventually brightened up and I went to an area that always provides early interest. This is the view looking north into an Ash wood with a stream along the right hand side.

View north into the Ash trees

Lesser Celandine is out all along the edge of the stream:

Lesser Celandine with Creeping Buttercup leaves to the right

No time is wasted before the fungal rusts appear. This is Uromyces dactylidis, which is common on leaves of various Ranunculus species, especially Lesser Celandine:

The fungal rust Uromyces dactylidis on Lesser Celandine 

And Puccinia lapsanae, which grows exclusively on Nipplewort. Notice that the rust has forced the leaf to grow a 'bulge', which serves to increase the available area for spore production/dispersal of the Puccinia:

Puccinia lapsanae on Nipplewort leaf

The ditch is also home for Opposite-leaved Golden Saxifrage, which has to be one of the most symmetrical plants I know:

Opposite-leaved Golden Saxifrage in flower

My last post showed an old mine of the micromoth Stigmella aurella on bramble. This leaf has at least 6 mines, some of which are currently occupied:

At least 6 mines of the micromoth Stigmella aurella on Bramble

This shot shows one of the micromoth larvae actively mining from left to right. Notice that the mine has abruptly turned right just before the margin: there must be something that the larva can detect that makes it turn before it is in danger of falling out of the leaf.

Larva of the micromoth Stigmella aurella

That shot is taken from below the leaf looking upwards, and shows light shining through the upper surface of the leaf, through the larva and through the lower surface of the leaf. Given that the leaf is no more than a millimetre thick, the larva is probably around 500 microns thick (and 3 millimetres long).

The ditch wall has many mosses and liverworts; these capsules belong to the moss Bryum capillare. Last year's capsules are still present, and the leaves of the Bryum can be seen to the bottom right of the image.

Capsules of Bryum capillare

Lastly for today, flowers of Hairy Bittercress, also known as Jumping Cress. If you want to discover the origin of the second name, just touch some ripe seedpods.

Hairy Bittercress (also known as Jumping Cress)

Green shoots of recovery

We've been having some very variable weather for the last couple of weeks, with about 15 cm. of snow at the weekend. The heat last week certainly stimulated some growth on the Raspberry canes:

First Raspberry leaves

I was a bit surprised to see a single flower of Germander Speedwell which has clearly suffered from the sharp dip in temperature that came with the snow:

Germander Speedwell

Leaf-miners always intrigue me, and the most common mine in this area is the micromoth Stigmella aurella. I often pause to have a look at the mine and see if I can work out the factors that determine the route of the mine:

Mine of the micromoth Stigmella aurella 

In this instance, the mine has started below right of centre and looped round a spot of rust on the leaf. It then heads for the central vein (which is the part of the leaf that's furthest away from the edge) and follows that vein for about half the length of the leaf. It then deviates outwards towards the edge (it has to do this at least once, since the central vein isn't long enough for a whole mine) and follows the edge without actually reaching the edge (how do they do that?) before turning back into the central vein to complete the mine.

The large fungal spots on either side of the vein are the fungal rust Phragmidium violaceum, which appears in summer and autumn as bright orange dots inside an expanding purple ring on the leaves.

Moth time

Moths get a really bad name, but I think they easily rival our butterflies for beauty and certainly for diversity (and for difficulty of identification - although the next few are easy enough).

This is the Small Magpie - Eurrhypara hortulata, which feeds primarily on Nettle:

The Cinnabar moth - Tyria jacobaea - is one of the most readily identifiable moths and is dependant on Ragwort:

A word about Ragwort: Ragwort is often blamed for the deaths of horses and cattle. I have spoken to many local farmers and they are unanimous that all animals will avoid eating Ragwort if it is left to grow. If the plant is pulled from the ground and left to 'sweeten', then animals can't differentiate it from hay and will eat it. That's when deaths occur. Leave Ragwort alone and it won't cause problems to animals, and will continue to nurture insects such as moths, hoverflies and bees.

The Brimstone Moth - Opisthograptis luteolata - has a fascinating life-cycle which enables it to adapt to varying winter conditions. Sometimes it overwinters as a larva; at other times as a pupa, the emergence date being governed by the type of overwintering strategy. It can be found as an adult from April to October, with some evidence for three generations over 2 years. Foodplants are shrubs and bushes such as Hawthorn and Blackthorn.

The most frequent leaf-miner on my patch is the micromoth Stigmella aurella, which makes leaf-mines on Bramble (and occasionally, on Meadowsweet). This is the (3mm!) adult:

Tachinid flies are parasitic on moth and butterfly larvae. This one became lunch for a Dung Fly. It's tough out there.

For some reason, this cock Bullfinch took a fancy to my rear door. It repeatedly flew at the rear window and then returned to the hosepipe winch. Perhaps it thought it saw a competitor in its reflection.

Still snowy

With fairly continuous cycles of snow, partial thaw then hard frost, higher areas are treacherous, with a very slippery top surface underfoot:


I did spot a badger trail, however, and took this shot of a footprint:


Very little new-season growth is to be seen, although there's just a hint of swelling on this Willow leaf bud:



So most of the visible wildlife is either perennial or last year's leftovers. This is the liverwort Frullania tamarisci growing on another willow twig:



Leaf-mines are very visible on last year's leaves of Bramble. These are shots of 3 specimens of Stigmella aurella, a micromoth:




Leaf-miners are always worth a look: the plant they live on can be a very strong clue to species, and it's interesting to see the strategies they use to avoid falling out of the leaf. Mines are made by some species of Flies, Sawflies, Micromoths and Weevils, and the shape of the mine can usually tell us to which family a particular mine belongs.