Lying in wait

At this time of year I am cheered by the thought that although there is very little wildlife to be seen at the moment, everything is just waiting for the moment that is its time to appear: everything is there, but we just can't quite see it.

Hidden plants can be resting as seeds, bulbs, corms or tap roots deep under the ground. Fungi have retreated back to the invisible mycelium which lies below the surface or inside wood. Many warm-blooded mammals and all cold-blooded reptiles and amphibians are hibernating in holes or under the surface of pools, lakes and streams. Molluscs are underground, either as eggs or adults.

But it is insects that have the most varied means of existing through winter. Most insects exist as one of four states: egg, larva, pupa or adult, although some insects - such as bugs - miss out the pupal state and go through a series of nymph stages, and insects can overwinter in each of those four states.

Queen bumblebees - already mated last year - are dormant underground and will emerge in early spring to look for a nesting place to lay the eggs that will become the workers. Similarly, the tiny nests of solitary bees have a small population of pupae that will hatch to create this year's generation. The males are nearer the entrance and will hatch first to establish territories before the females emerge. (This male-first hatching is quite common in insects, presumably to give the males a chance to exercise their fighting and survival skills to ensure stronger future generations. Another example of this is the Orange Tip butterfly, where the males emerge around a week before the females).

We have just under 800 species of micromoth in Ireland, and they overwinter in the widest range of places of any of our species. Some are inside the roots of buttercups; others are inside the seedpods of plants like Gorse; some are inside the stems of grasses, others are inside berries, seeds or fruits. A few leaf miners also make winter mines. Almost any stable or persistent location can be used as overwintering shelter.

Hoverflies overwinter mostly as pupae buried in mud or some other moist substrate such as rotholes in wood, or the roots of thistles, but a few overwinter as mated females ready to emerge when the first sun is around in early spring.

Butterflies also overwinter as pupae, but a few species hibernate as adults and might even be spotted out nectaring in milder days during winter. These overwintering species are the first emergers in spring and will breed to form a summer generation.

Parasitoids, such as ichneumonids, braconids or chalcids will have consumed the host pupae and will have pupated either inside the original pupal case or close by the outside of it. They will emerge when the next generation of host larvae are active and feeding later in the year.

Flies are also quite diverse in their overwintering habits. Some have developed inside the seedheads of flowers such as Knapweed and have pupated there. Others, such as leatherjackets (the larvae of craneflies) are underground after feeding on the roots of grasses.

Few beetles can be seen during winter: most are inside the pupal cases in wood, underground, or inside seedheads.

Aquatic insects such as diving beetles, dragonflies, damselflies, stoneflies and caddis flies are inside pupal cases under water.

So although it might seem that there's nothing around, there is wildlife near you no matter where you're standing.

Just as I was in the middle of writing this, my daughter found a lacewing in a package of Raspberries. The label said 'Product of Spain', so this must be one of the Spanish species:

Spanish Lacewing

I have no chance of an identification, so it will have to go down as 'Spanish Lacewing'.

(I wish to immediately disassociate myself from the purchase. They were priced down to 10 cents, and a student has to do what a student has to do).

Winter moths

We have a few moths that only emerge once the frosts have arrived. At first glance, this seems to be a flawed plan, since there is little vegetation to support caterpillars and the low temperatures are a hindrance to cold-blooded species (and none of our butterflies have this 'alternative' lifestyle plan). But a bit of investigation reveals that these winter emerging species might actually have a couple of advantages. Firstly, there are no ichneumonids or tachinids around to parasitise them at this time of year. Secondly, there is much less competition for any limited food resources that do exist. Thirdly, the eggs stay inert for a while, so their caterpillars don't hatch until fresh leaves are available, and they pupate before the real competition for summer food arrives. (This early pupation also provides some limited protection from parasites and predators). Furthermore, male moths are generally guided to the female by smell, and the summer moths can travel great distances overnight as they search for a mate, but many (not all) of the winter emerging moths have flightless females that stay in one place after they hatch. This means that the males have much less hunting to do to find a mate, which is a bonus in cold weather. There are some summer-hatching species with flightless females, so it would be interesting to know which came first: the winter hatching or the flightless females. More research, I think.

Here are a couple of winter moths which I photographed in December:

I photographed this very fresh (the abdomen is clearly still pink) Pale Brindled Beauty on the 19th of December, although its normal peak season is in March. This tied in with my sightings of Bumblebees, Celandines, and Willow leaves and catkins all around the same time: all of those would be much more normal in March than December.

Pale Brindled Beauty

I have subsequently discovered that this is the earliest ever date (by one day!) in Ireland for Pale Brindled Beauty to be recorded.

I also saw the very handsome Mottled Umber on December 25th:

Mottled Umber

At first I thought that this was a new species for me, because I had certainly never seen the moth before, but my records show that I had photographed the caterpillar in 2006 (you can see it here). So it's a new adult moth, but not a new species for me.

Both of these moths feed on leaves of a wide range of trees when caterpillars. In each case, the photographs show males, because the females of both species are wingless.

For the last week or so, the wind has been mostly from the south, and I received reports that immigrant moths have been found in the south of the country. I didn't think that they would bother at this time of year: perhaps it's yet another sign of a mild winter to come.

Update

A bit of sun today, so I went out to see what was happening.

A check of the usual ditch turned up a single flower of Lesser Celandine along with a few buds:

Lesser Celandine flower and bud

This area is sheltered by Ash trees, so I suppose it will be a bit more exposed next year or the year after.

Most fungi have been killed off by the recent frosts, but a few are still emerging. This little Mycena arcangeliana was growing through moss at the base of another Ash.

Mycena arcangelicastri

I spotted a new liverwort on a dead branch nearby:

The liverwort Radula complanata

It keyed out quickly to Radula complanata, which is described as 'epiphytic on wood in areas of high rainfall'. Bang on.

New to my Species list.

In my last post, I mentioned that some lichens reproduce by growing on unstable substrates, such as crumbling soil on embankments. This specimen of Lepraria incana is growing on the surface of moss:

Lepraria incana on moss

I took time to update my Species list with the recent new additions, and the grand total is now 1461 species. I suppose the magic 1500 might arrive next year.

Species recorded by year

The rise in number of species is remarkably constant since 2006, when I started to record everything I could identify.

Lichens and leaves

Just when I thought the season couldn't get any more odd, I spotted a Willow making new leaves on a couple of shoots:

New Willow leaves

This is the same Willow specimen that has the opening catkins on it, so it has obviously been thoroughly confused: the leaves on this specimen of Willow normally appear after the catkins, rather than at the same time. I have received reports that Daffodils are making good growth in a nearby location, so something odd is happening.

This is a good time of year to have a look at lichens. Although they are present all year round, they are often hidden by leaves and plants, so they are now more visible and accessible.

Lichens are a combination of a fungus and a photosynthetic partner. They are usually described as a symbiotic relationship between the fungus and either an alga or a cyanobacterium, but I see it more as a boss-victim relationship for reasons that I have previously explained numerous times. Either way, lichens can be found in wildly varying shapes and colours and are very important as pioneer species, converting wood and rock into soil over time.

There are several reproductive strategies used by lichens: some create fruit bodies which are purely fungal, and eject spores into the atmosphere in the hope that they will land on a nearby victim in order to create a new specimen. Others create little packages of fungal material combined with trapped algae which are ejected as 'starter packs' of lichens ready to go. Still others grow on fragile material such as soil and simply fracture into a new specimen.

Some lichens use more than one of these reproductive techniques, and can therefore be found in different states, depending on which strategy they have currently chosen. This specimen of Hypotrachyna(Parmelia) revoluta is very unusual, in that it has produced purely fungal fruitbodies. One is visible just to left of centre:

Hypotrachyna(Parmelia) revoluta with fruitbody (orange)

Hypotrachyna revoluta is very much a western species and can be found mostly on wood, but sometimes on rock. New to my Species list.

Ramalina calicaris, on the other hand, regularly produces fruitbodies, and they can be seen here as little cups on the tips of most of the branches:

Ramalina calicaris

The orange material to the lower left and upper right of the branch is the alga Trentepohlia, which is one of the victims of choice used as part of many lichens. It is no coincidence that Trentepohlia and lichens are often found in the same location, since the lichen has probably formed principally due to the prior existence of the alga in that precise location.

Evernia prunastri is readily identified by the bifurcating branches, which make it look like antlers:

Evernia prunastri

The upper surface can be grey or green, but the underside (shown) is almost white.

Platismatia glauca is another new species for me. It is usually found on the upper side of horizontal branches:

Platismatia glauca

New to my Species list

Lecanora chlarotera is a very common lichen on Willows. I think there are few trees without some of this somewhere on the trunk:

Lecanora chlarotera

I love the colour of those fertile fruitbodies, somewhere between olive and brown. Notice how straight the line of fruitbodies is on that sample. I have a strong suspicion that these lichens are spread by slugs, perhaps even after the spores have passed through them and been left in the trail they leave behind.

Peltigera sp. lichens have very leafy structures and can grow very large. This specimen has been tentatively identified as Peltigera lactucifolia, but the orange fruitbodies seem to be the wrong shape (round, rather than elongate). Research ongoing by the good and great, but I think it's actually Peltigera horizontalis.

Peltigera cf. lactucifolia

Pannaria rubiginosa is a very attractive lichen with a distinctive appearance:

Pannaria rubiginosa

The victim in this case is the cyanobacterium Nostoc, which can often be found as a green/brown jelly on paths and carpark surfaces.

That's another two species for my species list, which must be nearing a total of 1450. I'll update it before the year runs out.

Synchronisation

Each year, species come and go with the seasons: in spring we have the early flowers, such as Snowdrops and Primroses. In summer we see a wide profusion of insect life, and in autumn we find fruits and fungi. On this grand scale things are pretty much set: we won't find many butterflies in mid-winter and few fungi are seen in spring. But within this fixed schedule there is much fine-tuning: each year has different weather, leading to different temperature and humidity on any particular day in different years. This difference can cause annual variations in flowering and emergence dates, so although the general trend is predictable, the precise dates of first (or last) sightings are not: each year is different. Within this variable environment, however, all is not random: we have synchronisation to consider. Synchronisation is a fundamental driving force in our wildlife: when there is a strict dependency between two (or more!) species, they must be together at the correct time. For example, if a larva eats the leaves of a particular plant, then the larva needs to hatch when the leaves are available. The larvae of many moths and butterflies fit into that category. This synchronisation can be quite 'soft' - a few days won't make much difference to availability of the correct food - but other species need a much tighter synchronisation. If a parasitic wasp lays its eggs into the larvae of flies that eat particular fungi, then:

• the fungus needs to be in place
• the fly needs to have laid its eggs in the fungus and 
• the larva must be nearing full size.

Considering that the life of a particular mushroom specimen can be as short as a few days, we can see that the synchronisation required for this parasitic wasp to be successful is extremely tight: its annual opportunity is measured in hours.

So what governs this synchronisation? On the grand scale, we have the year: the amount of time it takes for our planet to go once round the sun. Most lifecycles are governed by this unit of measure. Then we have the day: the amount of time it takes the planet to turn once on its axis. These units of measure are absolutely consistent (within the lifetime of our observations). But what is much more variable is day length. The shortest day is 21st December, with the longest being 21st June. The day length follows a sinusoidal curve between those dates and is the major indication of time of the year. If you know the day length, you know that it can only fall on two particular days of the year. And it's this dual identity that leads me on to the first of today's pictures.

In springtime, I expect to see Celandines and Willow catkins as the first signs that a new year has begun. Over the past few years, I have seen Celandines in late November. This is clearly the wrong time of year, since winter is just arriving: ice is imminent, which will cause flower damage and there will be no insects to help with pollination. But if you look at the 'proper' flowering time (February around here), you will see that the 'proper' flowering date and the 'wrong' flowering date are an equal distance from the shortest day: the day length is roughly the same in each case. So the plants have detected that the day length is correct, but have failed to notice that the overall trend of day length is decreasing rather than increasing. Something is causing confusion.

When I find the early Willow catkins, the first pollinators to be seen are queen bumblebees and early solitary bees such as Andrena clarkella. These bees need Willow pollen to get their annual nests started: their larvae will feed on this pollen, so the bees are stocking up from the only pollen supply that is available. (I should point out that Andrena clarkella is a prime example of synchronisation: the female gathers only Willow pollen, so she can be seen only during the Willow pollen season, which is around 60 days long. When it comes to the bumblebee, the synchronisation is tight for the queen, but more relaxed for the workers, since many flowering plants will be available when they hatch.)

I previously mentioned that I had seen a queen Bombus terrestris gathering pollen on two occasions recently, and wondered where her workers were going to get pollen over the winter. This weekend, I found out:

Willow catkins

Willow catkin opening

I have never seen Willow catkins opening before February, so this was a huge surprise. Queen Bombus terrestris have been known to make overwintering nests in the south of England, but I was still very surprised to make two sightings of a working queen this far north in late October and mid November. It appears that both the bumblebee and the Willow have been triggered by the same stimulus and have both synchronised at the wrong time. It will be interesting to see how this all develops.

Moving on to things at the 'right' time: now is a good time to look at mosses. Most mosses need microscopy to identify for the first time, but once the initial identification has been made, most species can be readily identified in the field. I spent some time photographing specimens on an old wall at the south of the town.

Homalothecium sericeum can be identified by the pale, pointed growing tips:

Homalothecium sericeum

Tortula muralis can be found growing on wall tops:

Tortula muralis (with Grimmia pulvinata in background)

The setae ('stalks' that hold up the capsules) catch the light very well. I'd love to think that they act as light pipes to drive sunlight deep into the base of the plant. I have previously covered the complex lifecycle of mosses, (here and here) but for now I'll point out that the setae and capsule are not wholly from the original plant, but are partly a junior generation that is parasitic on an older generation.

Most mosses have setae that carry capsules well clear of the parent plant in order to maximise the opportunities for spore dispersal. Grimmia pulvinata continues to puzzle me by its insistence on burying its capsules under the leaves of the parent plant:

Grimmia pulvinata showing 'drooped' capsules

Orthotrichum anomalum can be tricky to identify due to its extreme similarity to other mosses, and also due to a high degree of variability when wet or dry:

Orthotrichum anomalum

Growing on the same wall, I found:

The lichen Caloplaca flavescens, which normally dies away in the centre, although I think this specimen has had some assistance from molluscs:

Caloplaca flavescens

And Ivy-leaved Toadflax, which I think flowers here all-year round, now:

Ivy-leaved Toadflax

Just to add to the absurdity of the flowering Willow, here is a shot of Galerina clavata taken on the same day on my lawn:

Galerina clavata with frost

Smaller things

I was wondering how the queen bumblebee from October 28th was doing, and this morning we had a gap in the rain. Sure enough, at around 10 am, she was back at the Lavatera in the garden. (Well, I'm assuming it was the same one. Either we have two queens, each making a winter nest, or one queen working hard at getting her winter nest established. Either way, it's a notable observation.) I had hoped to follow her flight, but she went quite high and flew south so, sadly, her nest isn't all that close to me. It will be very interesting to see if we start to get B. terrestris workers in the next few weeks. Having said that, we had the first frost of the year last night. It was only a couple of degrees below, but a frost all the same. Here's a shot of the roof of my car:

Frost patterns

When the weather is on a bad run it's time to gather some samples and do some microscopy and deeper research.

There's a little mushroom that appears on my lawn several times a year. I know it's a Galerina, but today I decided to get it to species:

Galerina clavata

I put a specimen on a glass slide and waited overnight for a spore print. Here's the print on the slide waiting to be examined under the microscope:

Galerina spore print on the microscope

You can clearly see the brown spore print in that shot. (The blue column is the light shining up on the underside of the slide.)

We need to examine spores at a magnification of at least x400:

Galerina spores at x400

These spores are described as 'almond-shaped'.

I noted that the base of the stipe on the specimen was woolly white, so that makes it Galerina clavata, a common mushroom in association with mosses in lawns.

Liverworts are amongst our most overlooked plants. They are mostly tiny, and many could easily be assumed to be mosses. An in-situ shot would show nothing recognisable, so I took this shot (sample size about 3 cm. across) on paper in the study.

Liverwort sample about 3 cm. across

There doesn't seem much to work with there, but once you get a sample under the microscope, everything becomes clear. This sample is mounted on a slide ready for the microscope:

Liverwort sample on slide ready for microscopy

Note that the individual leaves have no central vein - a clear indication for a liverwort. There are no underleaves, and the leaves look to be entire, without lobes or teeth. Microscopy, however, reveals that the leaves are very slightly toothed - more so in the lower leaves - and that the teeth contain very few cells:

Cells in leaf tooth

All of this leads us to Plagiochila porelloides, which in this case is the predominant plant on the rear wall of the ditch where I found it.

I'm currently working on lichen microscopy. This is a specimen of Xanthoria parietina, an extremely common lichen that can be found on wood or stone and even on glass:

Xanthoria parietina

Lichens are an association between a fungus and a photobiont (either an alga or a cyanobacterium). Since the fungus is the only part of the organism that reproduces freely, I refuse to see this as symbiosis: I consider that the fungus (which needs the photobiont in order to survive) is virtually parasitic on the alga (which can and regularly does live happily on its own, without help from the fungus). This shot at x30 shows the circular cups which are the spore-producing, reproductive part of the fungus:

Fruit bodies of Xanthoria parietina

Brave new moth

Our moths have a wide range of breeding and overwintering strategies: some overwinter as eggs, others as larvae, still others as pupae and a few as adults. These patterns are largely governed by the availability of foodplants, but are also affected by the length of time that the larva takes to grow to full size. That latter aspect will be further complicated by the nutritional content of the food and the efficiency of conversion by the larva of leaf into flesh. Some larvae mature very quickly, giving rise to the possibility of multiple generations per year, but the majority of our moths have a single generation each year. This is quite convenient for those of us who try to identify moths: we can usually eliminate some possibilities due to the month when we find specimens but, again, there are complications. Heat clearly plays a part in this cycle, and some species are bivoltine (having two generations) in the south of the country but only one in the north, and as we are warming, the interface between the univoltine populations and bivoltine populations is slowly moving further north, so identification strategies are having to change over time. Add to that the fact that some previously univoltine species are now becoming bivoltine in the south of the country, you can see that we are constantly having to reconsider matters that were previously facts, but are now merely indications or simply wrong.

The Red-green Carpet has a cycle where the larvae feed on leaves of trees during the year and then pupate to emerge around now. The adults mate and the female goes on to overwinter, but the males die off. When the new leaves arrive in springtime, the female will come out of hibernation to lay her eggs and next year's single generation will be under way. So in this case we have the unusual 'seasons' where both adults are found from September to November, but with the female also being seen in March to May.

Given the very short breeding season, I suppose it's not all that surprising that this species will fly when others refuse to endure the rain or cold, and yesterday I found this specimen on a door-frame just as we arrived back from walking the dogs:

Red-green Carpet - Chloroclysta siterata

Red-green Carpet can usually be identified by the reddish streaks that run along the wing, but these are sometimes absent, and we have to rely on other features, such as the white 'chevron' near the trailing edge. The above example is a female.