January 2019

Wallaroos (Hill Kangaroo) Male and female

Wallaroo - male

As you may have guessed from the picture accompanying this column, I am writing this from Australia where I suspect it is a bit warmer than it is in Pett right now.   In Australia, my daughter-in-law puts out seeds for the birds just like we do in the UK, but the range of species that are attracted to the garden are very different.  In the UK we expect to see bluetits, great tits, goldfinches, etc., in other words the commonplace birds.  In Australia we get the commonplace birds as well, but commonplace in Australia means sulphur-crested cockatoo, king parrot and rainbow lorikeets.  The feeders are different as well – parrots’ beaks would make short work of our plastic and metal feeders, so in Australia they use small metal dishes firmly screwed to the balcony rails.  It is, of course, the commonplace that defines the country or region.  There are exotic rarities here, just as there are in the UK, it’s just that they are different rarities, but to get the character of a place you need to concentrate on the everyday common species.  When William Smith compiled his geological map of Britain in 1815, one of the clues he used to determine the underlying rock types was the type of common plants growing above, because plants are determined by the soil type and the soil type is determined by the rocks beneath.  Common plants are common because they are successful, and they are successful because they suit that particular ecological niche, in this case, the soil.

Sulphur-crested Cockatoo

..and a bit closer

Another difference in the birds here is that they are nowhere near as nervous as our UK birds.   I can sit on the balcony typing this with a sulphur-crested cockatoo literally within reach.  This allows me to study them easily and the most striking thing about the cockatoo (apart from its showy crest) is its feet.  It has quite short legs and walks with its ‘heel’ on the ground.  (Birds don’t really have heels.  The joint equivalent to our ankle is normally halfway up the bird’s leg which is why flamingos look as though they have got their knees on back to front.)  This gives them a curious waddling gait but also a stable platform when stood on one leg.  Give a cockatoo a piece of bread and it will hold it in one claw and take bites just as we would eat a sandwich.  Also, when the bird has taken a large seed or a nut it will wrap its claw round the end of its beak so that nothing escapes when the seed cracks open.  For such a big bird (they are about the same size as a buzzard!) this gives them a certain gentleness that you wouldn’t imagine from hearing their almost deafening raucous calls.

King Parrot Male

I visited the Australia Botanical Gardens yesterday and despite the rain, I managed to get some photos of wallaroos that live in the gardens. 

King Parrot (female) - Queen?

(The gardens cover 416 hectares which is over a thousand acres so there are plenty of wild areas for them.)  This involved wading through some long grass to get close enough to the wallaroos.  When I got home, I noticed that my socks had sprouted long wiry hairs and something was pricking my ankles.  On investigation they turned out to be grass seeds, but pulling on the wiry bristle didn’t work, I had to push the seeds through the sock to get them out.  This was because at the base of each seed there was a number of stiff backward pointing spikes that acted like barbs.  I assume that this was an adaptation whereby the seeds, which presumably evolved before socks did, worked deeper into the fur of animals so that they were dispersed further. 

Rainbow lorikeet - I wonder why it's called that?

...and still closer  - admiring its reflection in the lens

Spiky grass seeds - I will try and identify the plant next time.

December 2018

I was saddened to (belatedly) read of Dave Saunders’ experience with hornets in October’s Pett and Pett Level News.  He clearly had a lucky escape.  I still think that they are magnificent insects but I would always recommend treating them with caution.  Both wasps and hornets behave differently around their nests than when they are out foraging.  If one stings you away from the nest because you accidentally disturbed it or it got caught in your clothes, it will be a defensive sting and it will fly away once it is free.  If, however, you are nearer to its nest, and it feels that you are a threat to its colony then when it stings it will release pheromones that will effectively ‘call out the troops’ and attract others to assist.  So Dave did well to run inside, and I expect that the colony has since been destroyed.  I am a nature lover but sometimes, reluctantly, it needs to be controlled.

I am writing this in mid-November and though the leaves on the trees have finally started to assume their autumn colours, many are still in full leaf.  Many plants are still in flower –we even have some self-seeded broad beans in our vegetable patch in flower at the moment, though we are not expecting them to produce any sort of crop, even if there is anything still around to pollinate them.  There are still a few butterflies around and I still find the occasional caterpillar on next year’s brassicas that should have been safely left alone by now. If autumn continues to get later and spring continues to get earlier, we will soon have nothing left to call winter and we will just have year round strange and violent weather.  The recent IPCC report that warned of catastrophic climate change unless drastic action is taken now, seems to have been ignored by the government, who despite their current preoccupation with Brexit, have done nothing to promote green policies, in fact, quite the reverse.   (The news today reports that a government advisory panel has at last seen the link between meat production and climate change, so maybe there is some hope.)

But does it matter?  I wrote last time about various species moving northwards, which is interesting but otherwise not normally a problem.  I think that the real problem as far as the natural world is concerned (aside from the violent weather events) is a matter of timing.  I came across a case recently that illustrates this well.  One of our scarcer plants is the Early Spider-orchid.  This is very similar in appearance to the more common Bee Orchid and the flowers attract bees in a similar way. (I wonder why it’s called a Spider-orchid!)  They are pollinated by a rather vaguely named solitary bee – the buffish mining bee (Andrena nigroaenea should you wish to address it formally) and the flowers emit a scent that resembles that of the female buffish mining bee, so that the male will be attracted to the flower.  In most species of solitary bee it is the male that emerges first, and the females usually appear up to a couple of weeks later.  So for the Early Spider Orchid, the best strategy is to flower after the males emerge, but before the females emerge.  If it flowers either before the males emerge, or after the females emerge, then it stands much less chance of being pollinated, and that timing is going wrong so the Early Spider Orchid is one of the many plants in decline.

Bee Orchid

The Early Spider-orchid is just one example and there are many more.  Evolution over millions of years has ensured that plants and animals make the right connections, whether that is blue tits relying on oak caterpillars to feed their chicks, or ivy bees pollinating ivy.  It has taken millions of years to get the timing right, and we have managed to screw it up in less than 200 years.  Depressing, isn’t it?  But there’s so much beauty still out there, whether it be a hornet, a stray late butterfly, or the autumn colours, so go out and enjoy it and protect it when you can.

Yellow-legged Mining Bee

Female Tawny Mining Bee - definitely tawny and not the least bit buffish

November 2018

One of the really pleasurable aspects of writing these Nature Notes is that people come to me with nature-related questions or send me photos of things to identify.  Most of the time I have a good idea of the answers, or at least a good idea of where to go to look for the answer.  One question was “Why so many crane flies?”.  My answer (Perhaps because of the dry summer making the ground hard and so difficult for birds to eat the leatherjackets.) was completely wrong.  The correct answer is the wet autumn of 2017 which allowed the leatherjackets to thrive, and also, the fact that certain insecticides have been banned which used to poison the leatherjackets (and lots of pollinators too!).  But at least I now know, and I had the pleasure of trawling the internet to look it up.

One of the Facebook groups I belong to also spawned a trawl for more information.  Somebody had opened a bird box that had been home to a bumblebee colony and was asking what the white fibrous material was.  Somebody had answered that it was the silk of Aphomia which is a parasite of bumblebees, honey bees, and wasps.  So I then wanted to know what Aphomia was – it is better known as the Bee Moth or Aphomia sociella. 

Bee Moth - Aphomia sociella

The female bee moth lays her eggs in the colony early in the season – i.e. before the first workers hatch to build up the colony’s defences.  When the bee moth larvae hatch they will eat eggs, bee or wasp larvae, and any pollen or nectar they can find.  (The caterpillars spin a particularly strong silk cocoon to protect themselves while feeding.)   So if you do clean out your bird boxes – and now is a good time to do it – then please destroy any caterpillars you find in there, and just be aware of queen wasps that often use nest boxes to hibernate in.  If you want to attract birds to your nest box, then clean out any old nesting material, but if you want to attract bumblebees, then leave the nesting material in there, or better still get another nest box and do both.

One interesting thing that I found out about bee moths was their mating habits.  Most female moths emit pheromones when they are ready to mate, and most male moths have large feathery antennae so that they can detect them.  In the case of male bee moths, they also emit their own pheromones to increase their chances of encountering a female.  But the really interesting thing about the male bee moth is that he has another weapon in his charm arsenal – he can emit ultrasonic ‘chirps’ in much the same way that cicadas do so that the females can more easily find him.  What I’d be interested to know if I was a male bee moth is – can bats detect my ultrasonic ‘chirps’?  I also found out that the sound is emitted from the tegular tymbals, but nobody needs to know that unless they accidentally come across a pair.

To move away from the endlessly fascinating world of insects for a moment – there are a lot of jays about just now.  There a lot of jays about all the time, but at this time of year they are collecting and caching acorns and other seeds, and so are more conspicuous.  They are the most colourful of the crow family with their beautiful dark pink plumage and pale blue wing flashes.  Like other members of the crow family they are very intelligent and will remember where most of the seeds are buried so that they do not starve through the winter when other food is scarce and energy demands are high.  One fact about jays that can help with identification is that they are the only crow-sized bird with a white rump, a useful feature since most birds are seen when flying away from you.

It seems to be a good year for parasol mushrooms.  They’re edible and delicious fried in a little butter.

Stop Press:  An Asian Hornet has been spotted at Dungeness.  The Asian hornet is more of a threat to honey bees than its larger cousin the European hornet.

When this article went to press for the printed version, I had confused Bee moths (Aphomia sociella) with the similar Wax Moth (Galleria mellonella).  The Wax Moth is normally found in honey bee hives as its larvae feed on honeycombs - particularly old honeycombs so that they are less of a burden to the colony than Bee Moths.

October 2018

You may remember that last month I wrote about hornets feeding on wasps.  I suspected that they leave the wasps’ abdomen because there is more protein in the thorax where the leg and wing muscles are located.  On a recent visit to Belgium with the short-haired bumblebee project, we met up with some Dutch and Belgian entomologists.  I was talking to one of the Dutch entomologists about the hornet and he confirmed that they only take the thorax for its protein content.  He also said that they don’t eat the thorax, but rather they mash it up into a manageable meatball and carry it back to their nest to feed the growing larvae.  Like their more useful cousins, the honey-bees, they make a bee-line for the nest.  Apparently, Holland has been dealing with the westward spread of the Asian hornet for a while now and they use this ‘bee-line’ habit to locate their nests.  All they need to do is to find a hornet and when it flies off with its meatball, plot its direction on a map.  When you have watched and mapped two or three hornets in this way, where the lines intersect shows you where to look for the nest, which can then be destroyed.  This may well be useful knowledge since as recently as the 11^th of September, Asian hornets have been spotted in Cornwall and East Yorkshire.

Great Green Bush-cricket - female

Another group of insects that we saw plenty of in Belgium were bush-crickets.  This is a striking group of insects and they are remarkable for the length of their antennae which can be many times longer than the rest of the insect.  We saw the great green bush-cricket, which as its name suggests is big and green.  The body can be up to 40mm long, and with an ovipositor another 20mm and antennae three times longer than its body, it looks a formidable insect.  I first came across one of them at Dungeness and my first reaction was one of disbelief.  It was bending the vegetation that it was crawling across.  Though large, they are well camouflaged in green vegetation and can move fairly quickly.  You are more likely to hear them before you see them as they have the loudest stridulation (chirping!) of any of our grasshoppers or crickets. 

Great Green Bush-cricket - male - showing just how big they are

We also found one species of bush-cricket that you are less likely to find around here - the sickle-bearing bush-cricket.  These were spotted in Hastings Country Park a couple of years ago, but have since disappeared again.  However, like many insects, global warming is inducing them to march northwards, and there have been other sightings around the country so if you see a bush-cricket with a sickle-shaped ovipositor, then take a photo – it may be a sickle-bearing bush-cricket – and the people who monitor such things want to know about it.

Sickle-bearing Bush-cricket - on my hand

I recently found one of my favourite bush-crickets – a speckled bush-cricket, on some red-leaved kale that we are growing.  Being bright green, it stood out well on the dull red of the kale.  With its long-legged awkward gait and its slightly goofy face, anybody would find it endearing, wouldn’t they?

Speckled Bush-cricket

Dave Clarke has recently had a small infestation of solitary bees in his garden.  They are probably ivy bees, another species on the march northwards (first seen in the UK in 2001).  I say probably, because there are two other very similar species – the sea aster bee and the heather bee.  (Dave's bees have since been confirmed as Ivy Bees.)  They are all called plasterer bees because of their habit of lining the cells that they dig in soft ground with a smooth cellulose substance.  You’ll have noticed that each of these bees is named after the plant that it prefers to feed on.  In Belgium one of the Belgian entomologists caught and identified a solitary bee from the fact that it was feeding on purple loosestrife, (which incidentally has green pollen).  It was one of the blunt-horn bees (Melitta nigricans) that we don’t get in the UK – yet!

Ivy Bee - Colletes hederae

September 2018

Underneath our apple tree are a large number of windfalls varying in state from eatable to completely rotten.  One reason (excuse?) for leaving them there is that it feeds the wildlife.  One of the main species to feed on the apples are wasps, but I was delighted recently to see a hornet cruising around the windfalls.  I was delighted because though they may be fearsome to some, to me they are a magnificent insect.  I have seen hornets feeding on the apples in the past, but this one had a different purpose in mind.  It flew towards an apple on which a wasp was already feeding.  There followed a surprisingly lengthy scrap between the two insects, but the outcome was never in doubt and by the time I got back with my camera, only the abdomen of the wasp remained.  Not sure whether there was any life left in it, I carefully nudged it onto a handy leaf and carried it out of the shade of the tree to get a better look.  I was wise to be so careful because within a minute or two, the abdomen suddenly started to try and sting anything within reach.  Clearly the hornet had stung the wasp to subdue it but the effect had gradually worn off.  A careful examination of the grass under the tree revealed several more stray wasp abdomens which suggests that wasps are a large part of the hornet’s diet.  I am guessing that it takes the head and thorax because there is more protein in the thorax due to the leg and wing muscles being in there.  

Wasp abdomen - still dangerous

European Hornet Vespa crabro about to behead a hoverfly 

Apparently a hornet sting is no more painful than a wasp or bee sting, each rated at level 2 on the Schmitt pain index, and each lasting around 10 minutes.  The pain index was compiled by the American entomologist Dr. Justin Schmidt, who wanted to know if social insects had evolved better defences than solitary insects because of their greater investment in the colony.  He allowed himself to be stung by more than 80 different species in order to compile the index.

On a similar note, we thought we had seen several hornets feeding on ivy flowers when we visited Kew Gardens recently.  Closer examination showed that they were in fact Hornet Hoverflies.  This insect also goes by the catchy title – Volucella zonaria.  It is a very convincing mimic and Britain’s largest hoverfly and is an example of what is called Batesian mimicry where a harmless species evolves to look like a much more dangerous species to avoid being eaten by predators.  This type of mimicry is named after a Victorian entomologist Henry Bates who first described the phenomenon.  He was a contemporary of Charles Darwin, and travelled to South America in 1848 with Alfred Russel Wallace who came up with the theory of evolution at around the same time as Charles Darwin.  Wallace returned from the Amazon four years later, but Bates stayed and studied mostly the insect life there for another 7 years, sending back thousands of specimens, many of which were new to science.  His collection survived the crossing back to Britain and in that he was more fortunate than Wallace, whose collection was destroyed by fire in a shipwreck on the journey back.  Bates wrote a very interesting book about his experiences – The Naturalist on the River Amazons – which is a classic of nature travel writing.  The hornet hoverfly also uses its mimicry in another way – to escape detection when it lays its eggs in the nests of hornets, wasps and bees where the larvae eat detritus around the nest.  A dangerous strategy indeed.

Hornet Hoverfly - Volucella zonaria

August 2018

In the June Nature Notes, I mentioned seeing a barn owl flying over the field at the back. 

Not the barn owl mentioned in the text, just the best shot of one that I've got

Well we have seen it several times since then, each time carrying prey and it appears to be nesting in a dead tree at the back of one of the houses on Pett Road, possibly Wetherdene?  A few days ago as we were sat by the pond sipping an aperitif and watching the sunset, we were alerted by a lot of screeching and flapping.  It all happened very quickly but basically, a kestrel was mobbing the barn owl which eventually dropped the prey which the kestrel followed down onto the field.  The barn owl then flew back towards Pannel Valley.  Only a few minutes later, the barn owl was back again with more prey.  I suppose that it is possible that the returning barn owl was the other parent that had already caught another vole while the first was being mobbed as male and female are almost identical.  (The male is slightly paler apparently.)  Another possibility is that the mobbed barn owl deliberately dropped the prey to avoid being followed back to the nest by the kestrel. 

Mobbing of owls by kestrels is well documented on the internet and many people have managed to take photographs or videos.  Sadly the only thing I had to hand at the time was a glass, but even if I’d had my camera with a long lens already switched on I doubt that I would have got even a blurry photo, it all happened so fast.

 ‘Our’ swallows have successfully fledged four chicks this year and it was delightful to watch them sitting on one of the beams in the carport waiting to be fed.  That only happened for a few days as they find their wings and fly increasingly longer distances and eventually come back only to roost.  We’ve not seen the youngsters for a while now, but the parents are busy preparing for the next brood.  The house martins seemed to be late nesting this year.  There is a nest at the front of the house as well as one at the back.  Both nests are from previous years, but that is not really surprising considering the shortage of mud at the moment.  The nesting habits of the martins are a bit mysterious.  Each year we see a lot of activity when the martins arrive back from Africa as they investigate each nest, but then it is often a month or more before they occupy the nest.  The nest at the front has three chicks, but the parents are still sitting on the nest at the back with no sign of hatchlings as I write this.

A while ago, I wrote about flying spiders – the process where freshly hatched spiders eject silk to catch the wind and help them to disperse – a behaviour called ballooning.  Recent research however, has shown that this is not the full story.  Some researchers at Bristol University suspected that naturally occurring electrostatic charges played a part (the sort that build up and cause thunderstorms).  They put spiders in a box inside a Faraday’s cage.  The Faraday’s cage shields the apparatus from natural electrostatic charges and allows the researchers to control the field inside the box precisely.  They found that increasing the electrostatic field encouraged the spiders to balloon and that once airborne they could raise or lower the spiders by changing the field strength.  A biologist also examined tiny hairs on the legs of the spiders that reacted to the field and gave the spiders the means of detecting the field.  Clever stuff indeed!

July 2018

In a recent ‘Nature Notes’ I talked about seed dormancy and rattled on about tough seed cases and scarification.  It turns out that I was completely wrong – or at least that wasn’t the whole story.  Listening to ‘The Life Scientific’ on Radio 4 recently, I heard Professor Caroline Dean explain the genetic and molecular basis of vernalization, the process that tells the seed when it is spring.  It turns out that seeds have a gene that codes for a protein that keeps the seed in a dormant state.  Cold weather turns the expression of that gene off.  However, it turns the gene off only one cell at a time so that it takes several weeks to turn all the genes off and stop the production of the protein.  This explains why seeds don’t suddenly start to sprout when we get a warm spell in mid-December.  Once all the genes are turned off, then the seed has to wait for all the other conditions to be right – temperature, moisture, day length, etc. – before growing into what should then be spring.  Interestingly, plants grown in colder climates take longer for this process than warmer countries with shorter winters.  So if you take seeds from Sweden and plant them in Spain, they will still need  say 10 weeks of cold weather when the native Spanish plants of the same species need only four weeks.

In last month’s Nature Notes I spoke about how interesting it was watching the solitary bees nesting in our solitary bee hotels.  It turns out that we weren’t the only ones interested in them.  One day we went out to find short bamboo tubes all over the patio, emptied of their content, with a corresponding huge hole in the bee hotel above.  We suspected that a woodpecker had learnt that it wasn’t only crevices in trees that contained juicy snacks, but we were open to other possibilities until further evidence presented itself. 

Note that the box on the right is unoccupied, mainly because the tubes are too big.

We didn’t have long to wait.  A few days later we were rudely awakened at 5 in the morning by a loud hammering on the back wall.  Opening the back door scared the great spotted woodpecker away and saved the bees from further carnage.  We still have two more bee hotels that are so far unscathed but we are seriously considering building some sort of woodpecker-proof cage round them.

While I was looking up woodpecker damage on the internet (of course it has happened to others), I found another interesting fact about solitary bee hotels.  The majority of bees in our bee hotels were red mason bees.  These emerge in spring and will have laid their eggs and died long before the end of June.  However, another group of solitary bees – the leaf-cutters, which are summer nesters – have now emerged and are looking for nesting sites.  If a red mason bee has run out of eggs or energy or life before completely filling the nest hole, then the rest of that hole may be used by a leaf-cutter bee.  (If you find almost circular holes in the edges of your lily leaves, it will be leaf-cutter bees that have taken the bits of leaf to seal up their nest cells.)  The problem with this is that the red mason bees will emerge first and will have to eat their way through the leaf-cutter cells thereby killing their occupants.  Life is tough at the bottom of the food chain!

June 2018

May so far has been an unpredictable month weather-wise. Weeks of unseasonal hot weather, interspersed with normal temperatures and chilly winds.  But nature is still getting on with things – we have blue tits nesting in their usual nest box (they don’t seem to like the shiny new one), ‘our’ swallows have returned to nest in the carport, and the house martins have been surveying a property in our eaves (only surveying so far, no sign of nesting or laying).  There have been a couple of other welcome events in the bird world – a cuckoo has been calling from the trees behind us for a week or so but he seems a bit hoarse as though he’s been over-cucking.  Hopefully a mate will have survived the trip back from Africa so that he can give his syrinx (voice box) a rest.  While we were sat in the garden watching the sun go down one evening, we saw a barn owl carrying some prey across the field at the back from the Pannel valley direction into the trees behind the field. 

Barn Owl (Norfolk)

We’ve seen barn owls in Pannel valley before, but never this far over.  The direction it was flying suggested that it has a nest in the trees behind the houses on Pett Road.  I’d be interested to know if anybody else has seen it.

We have also been fascinated by the activities of some other nesters – solitary bees.   These have been making use of our solitary bee hotels and have been working hard for a couple of weeks.  The first thing to attract our attention was a small swarm of male bees gathered round one of the hotels.  It was a very small swarm – never more than half a dozen individuals, and they were waiting for the females to enter or leave the bamboo tubes.  They may well have been out of luck though because any female nesting will already have been mated and from what we could see, none of the females were interested – entering and leaving the nests as quickly as possible.

Red Mason Bee Male. Note pale hairs on face and his passengers (mites)

Red Mason Bee Female, and you can just see her horns

The species of bee was the red mason bee (Osmia bicornis).  It is called the red mason bee because of the gingery hairs on their abdomen and because, if no bamboo tubes are available, they will dig themselves a tube by excavating holes in soft mortar.  In common with other solitary bees that nest in this sort of hole, the female will go to the far end and build a pile of pollen mixed with nectar.  She will then lay an egg on the sticky lump of pollen and seal up the hole, creating a cell in which the egg can hatch safely.  She will then build another pile of pollen and nectar in front of the cell, lay an egg, and so on, creating a series of cells along the tube until she runs out of room.  She may then go on to find another tube or she may run out of eggs or energy and die.  This means that there is no maternal contact between the adult bee and her offspring that won’t emerge until next spring, and everything that the offspring need to know about being a bee (including how and when to emerge) has to be coded in their DNA.

When the eggs hatch into larvae, they will eat the pile of pollen provided, spin a cocoon around themselves and go about the metamorphosis business, going from larva to pupa, and finally emerging from their cocoon as an adult bee.  The adult bee then stays in its cosy cell over winter, emerging when the weather warms up and there is nectar and pollen available so that they can feed themselves up ready to found the next generation.

You may have noticed the word bicornis in the scientific name, which is latin for two-horned.  This refers not to their antenna but to a couple of prongs on the female’s face which are used to tamp down the mud that they use to seal the holes.  The female doesn’t carry the pollen on her legs like other bees, but in the pale hairs underneath her abdomen. 

Ruby-tailed Wasp

Ruby-tailed wasps may also be seen near the nests which, though beautiful with their red and green metallic colours, prey on mason bees.  It was fascinating to watch the female bee carrying mud in her mandibles into the tubes and then, when the cell was sealed to come out, turn round, and back into the tube to lay her egg – several minutes, or hours well spent.

May 2018

I hesitate to say it, but I think spring is finally here.  There are cowslips in flower at the end of Pett Road where it joins Rye Road; there are wood anemones and lesser celandine all along Rosemary Lane, and there are bees feeding and nest searching in our garden.

Buff-tailed Bumblebee - Bombus terrestris

Two species of bee have particularly caught my attention – the buff-tailed bumblebee, and the hairy-footed flower bee.  The buff-tailed bumblebee can hardly fail to grab some attention.  For a start, it is Britain’s largest bumblebee so the queens are really easy to spot.  If that doesn’t get your attention then the deep throaty buzz of its wing muscles certainly will.  There seem to be a lot more queens about this year.  Maybe that is because the difficult spring has delayed their emergence from hibernation, or perhaps they had a successful year last year meaning that more queens went into hibernation and, being well fed, more survived hibernation.  Hopefully that’s a good sign for the coming season.

Hairy-footed Flower Bee, female in unusual pose, tongue out and
grasping the leaf with her mandibles

The hairy-footed flower bee could easily be mistaken for a small bumblebee, particularly the females.  It is a solitary bee (which means it doesn’t form colonies) and the male and female are very different.  The female is completely black except for some orange hairs on her hind leg, whereas the male is smaller and mostly ginger.  One thing that sets them apart from bumblebees is their habit of hovering and darting around flowers, so if you see what looks like a small black bumblebee hovering by your flowers, it has probably got hairy feet.  (That’s not actually true because it is the male that has the noticeably hairy feet that gives the species its name.)  Just like bumblebees they love the flowering currant and dwarf comfrey that are in flower in our garden at the moment.

But to go back to the cowslips at the end of Pett Road – I’ve never seen them there before, or at least never noticed them there.  This may be because of seed quiescence or seed dormancy.  Seed quiescence means that the seed is too cold, too warm, or too dry to germinate so it will wait until conditions are right.  Also, it may not be in the plant species best interest for all seeds to germinate at the same time – some flowering earlier or later may make a better use of available resources, or maybe flowering next year would be better.  But seed dormancy is slightly different.  Some species coat their seeds with a tough waterproof coating which seems an odd strategy at first when seeds need water to germinate.  One reason this happens is to stop the seeds germinating in late summer or autumn which would mean that the plant wouldn’t survive to set seed.  The frost will shift the soil around the seed and grate away or soften the seed coating so that water can penetrate, at which point the seed is ready to burst forth when spring finally arrives. (The technical name for this process is stratification.)  If there is no frost or the seed is too deep, then seeds may stay dormant for many years until conditions are better for them.  Gardeners wanting to short cut the process have been known to resort to the freezer and sandpaper to get their seeds to germinate.  It makes me wonder how coconuts manage!

April 2018

At a recent Gardening Club meeting we were introduced to many rare and unusual wildflower species, including a few parasitic ones.  One feature that immediately sets wholly parasitic plants apart from other plants is that they don’t contain chlorophyll, the substance that gives plants their green colour and is responsible for photosynthesis which allows them to convert the sun’s energy into growth.  (Note that there are many semi-parasitic plants like mistletoe and yellow rattle that do contain chlorophyll which means that they are less of a drain on their hosts.)

Toothwort (Lathraea squamaria) was the first plant mentioned.   This plant may be found in Alexandra Park where I have seen it growing in the undergrowth below some of the trees there.  Because it contains no chlorophyll, it doesn’t need a sunny spot to thrive, just as long as its host gets plenty of sunshine, though it does need to attract pollinating bumblebees which it does mainly by scent.  It invades the roots of trees and spends most of its life underground, only sending up the flower spikes in early summer.  It has an underground network of rhizomes which have pad-like tips (called haustoria) that attach to, and penetrate the bark of the host roots to get at the nutrients within.  The whole of the plant, including the underground parts are a pale creamy white.  It is not clear whether it gets its name from the resemblance of the flowers to a row of teeth or from the tooth-like scales on its roots.  Like all plants whose name ends with –wort, it was used medicinally for toothache, based on the doctrine of signatures.  It wasn’t commonly used, however, due to the plant’s relative scarcity.

Another parasitic plant mentioned was common dodder (Cuscuta epithymum), a member of the convolvulus family.  I know dodder from Dungeness Nature Reserve where it parasitizes wood sage.  It takes a different approach to toothwort in that its life cycle is completely above the ground.  When the seed germinates, it produces a root-like shoot that must find a host quickly before the energy contained within the seed is exhausted.  Once it has found a host, a sucker develops from which a thread-like stem grows which twines around the host stem (always anti-clockwise, or widdershins as we used to say before clocks were invented) and haustoria in the sucker and stem penetrate the host’s stem to extract nutrients. The root-like shoot then dies off.  As it nearly always kills or at least severely weakens its host, further stems reach out to neighbouring plants until a fine network of dark red stems cover a sizeable area.  It has no leaves because, like toothwort, it has no chlorophyll, taking all the energy required for growth from its host plant.  Small clusters of flowers form along the stems and produce seeds for the next generation.  The seeds can lie dormant for many years and it seems to favour disturbed ground, making it a common plant of managed heathland.  Dodder has also been used in traditional medicine as a purgative and for liver disorders.  Though native to Europe, it is now found on six continents; its spread is thought to be due to exported forage.  

The third parasite mentioned was a bit of a surprise as I was not aware of a parasitic orchid.  The bird’s nest orchid is another parasite that does not contain chlorophyll and this plant is a real specialist.  It parasitizes a fungus Rhizoctonia neottiae that is only associated with beech trees.  It is probable that the fungus has a symbiotic relationship with the beech trees, and it is also possible that the orchid provides some nutrition to the fungus via its roots which mesh with the fungal threads.  Apparently in Finland it is one of three different orchids without chlorophyll that are not related and are believed to have developed the same life cycle independently.  After flowering, the orchid and its rhizomes die off leaving only the tips of its roots which then grow into new orchids. 

March 2018

I have heard that grass doesn’t grow when the soil temperature is below 6 degrees C.  It is quite irritating then to find that despite the cold and dull weather that seems to have persisted for weeks, that our lawn needs mowing.  It’s even more irritating that it’s too cold and wet to get out there for the first mow of spring.  Grass is always a chore for gardeners, if it’s in the border it needs weeding out, if it’s not it probably needs mowing.

Unidentified, possibly Sweet Vernal Grass

It may however, be worth pausing as you empty the grass box, to marvel at one of nature’s most successful plants.  It grows just about everywhere from the high tide mark to well above the treeline and from the tropical rain forests to all but the driest deserts.  It comes in many forms – as grasses, sedges, and rushes, and even bamboo.  Incidentally, grasses, sedges and rushes are in separate families – Poaceae, Cyperacae, and Juncaceae respectively – and if you are not sure which is which then you need to remember the rhyme, ‘sedges have edges, rushes are round and grass stems are hollow right up from the ground’.  (That refers to the flowering stems which are triangular in the case of sedges.)  If you choose a grass species with fat seeds and fill a field with it, then you will have part of the world’s staple diet.  Where would we be without wheat or rice, or my own particular favourite, barley? (roasted and suitably mixed with another favourite native plant species Humulus lupulus, better known as the common hop.)  Another large part of our diet (too large in many cases) is derived from yet another grass – sugar cane.

Canary Grass

There are more than 10,000 different species of grass worldwide, and it is likely that your garden, however tidy you keep it, will contain a dozen or more different ones.  Identification of grasses is not easy and requires a lot of time looking for identifying features and following keys.  The botanical language used is different to that used for other plants because grasses have things like awns and stipules and spikelets that other plants don’t have.  Of course, the first thing you need to do to identify any type of grass is to stop mowing it and let it flower.  Grasses are wind pollinated and so they don’t need showy scented flowers to attract insects.  This means that the flower features are quite small and a hand lens is useful to see them clearly.  I have managed to identify a few species in our garden – Sweet vernal grass, which gives new mown hay its sweet smell, Quaking grass, Cock’s Foot, Field Wood-rush (a small but pretty species), Perennial Rye grass, and of course Common Couch grass.  Yet another species that I am trying to eradicate is Pendulous Sedge – if you have any, I recommend that you don’t let it flower!

Unidentified, possibly one of the False Oats

I find that the names of grasses have a sort of ancient and romantic feel to them.  Things like bents and fescues, crested dog’s tail, wood melick and canary-grass.  Believe it or not, there’s even one called Timothy.

Field Wood-rush

February 2018

I like writing this column because it forces me to check my facts before I write it and that means that I find stuff out.  We had some unusual visitors to our bird feeders recently – redpolls.  This was very unusual simply because we have never seen them on there before.  Redpolls are a small finch that breeds in this country, and we also get an influx from Scandinavia in winter.  When I looked up redpolls, it turns out that they could have been one of two species – the common redpoll, or the lesser redpoll.  Apparently these have only recently been split into two species, more recently than 2001 when my bird guide was published.  My bird guide did however, mention two sub-species depending on where in Scandinavia they bred, that correspond to the new species division.  So did we see Lesser Redpoll or Common Redpoll?  I haven’t a clue because the differences are small (one is slightly smaller and paler than the other) and I wasn’t expecting there to be two possible species when I saw them.  But it was a delight to see them and as long as they know the difference that’s all that matters.

Common or Lesser Redpoll - Carduelis flammea or cabaret

In last month’s column I briefly mentioned mosses and liverworts.  Apart from the fact that I could probably point out mosses or liverworts if I saw them, that was about all I knew, so I looked them up and it turns out that they are a very interesting group of plants.  As a group they are known as bryophytes and the group includes another set of plants that I had never heard of – hornworts.  Apparently hornworts are quite scarce in the UK which is probably why I haven’t come across them before (and if I had I probably would have thought them to be liverworts).  One thing about bryophytes is that they are not vascular plants.  Vascular plants (the plants we are more familiar with) have flowers, branches, and even trunks that contain sap which flows through the plant in a similar way to blood in veins – hence the term vascular.  Vascular plants grow, flower, set seed, which then germinate to form new plants, but bryophytes complicate matters with an extra stage. 

Bryophytes produce spores; those spores, usually dispersed by the wind, land somewhere favourable and grow into a new plant, but the difference between spores and seeds is that the DNA in seeds has the chromosomes from both parent plants, but bryophyte spores only contain the DNA from one parent.  (The technical term is haploid.)  When the plant that grew from the spore grows into a moss or liverwort, that stage cannot then produce spores.  Instead each plant is either female which produces eggs, or male which produces sperm.  The sperms are then usually dispersed by water (which is why bryophytes usually grow in very damp places) or by insects that carry sperm from one plant to another.  This egg and sperm stage is called the gametophyte stage, but you probably don’t need to know that.  The fertilized eggs are then dispersed from the gametophyte, again usually by water and having both the male and female DNA, they can then grow into the spore producing generation (called sporophytes, should you be interested).

From studies of their mitochondrial DNA it has been suggested that liverworts may well have been the first land plants to evolve from green algae more than 400 million years ago.  There are thought to be more than 1,000 species of bryophytes found in the UK and more than 20,000 worldwide. Though they are often overlooked, mosses and liverworts are an important part of the ecology and support a wide range of insects and other arthropods, not to mention the many birds that feed on those smaller creatures.  One day I hope to find a creature that makes its home only in moss – the tardigrade bear – that is almost microscopic and not actually a bear, but no less interesting for all that.

January 2018

Stag's Horn Lichen

Since the middle of November, the weather has been decidedly unfriendly, mostly cold, often dull and dark, and frequently wet.  Whilst many of us have been stuck in traffic jams on icy roads, nature has been getting on with it, or not depending on the species.  What I mean is that many plants and animals have been putting into place their survival strategy – lying dormant or hibernating or maybe just changing their diet to whatever is palatable and available.  One group of organisms that seems largely unaffected by the seasons are the lichens.  Unnoticed by many people, they are all around us growing on our houses, our pavements, and on our trees and shrubs.  There are about 1800 different species growing in the British Isles and identification is mostly for specialists, but they are interesting organisms with an amazing structure that can be revealed with only a simple hand lens.

Lichens are symbiotic, which means they are formed of more than one type of organism.  Usually they are composed of a fungus and an alga (singular of algae, in case your Latin is a little rusty), or a fungus and a cyanobacterium, or sometimes fungus, alga, and cyanobacterium.  Like the mitochondria, the symbiotic bacteria in our own human cells, the algae and cyanobacteria provide energy for the fungus, and in the case of the cyanobacteria, they also provide nitrogen that the fungus cannot otherwise fix. 

Crustose Lichens growing on Cherry tree bark.
The cups and bumps relate to spore production

There are four types of lichen that are based on the form they take.  There are crustose lichens; these grow on a surface, a rock say, and are completely attached to that surface – nothing sticks out from the surface.  You can find these on paving stones or on tree bark or a good place to find them is on gravestones.  Squamulose lichens are very similar but have a more scale-like structure. 

Crustose lichen growing on concrete

They can be very small and hard to distinguish from crustose lichens.  Foliose lichens are, as their name suggests, leaf-like and the ‘leaves’ are only attached to the surface at their base.  Fruticose lichens are more bush-like and can look more like hair or coral – you will find lots of fruticose lichens on the shingle at Dungeness or Rye Harbour, but you are just as likely to see them growing on your apple tree, though they may well be different species.

One very useful service that lichens perform is as indicators of air quality.  They thrive on clean moist air, but can be wiped out by polluted air.  By counting the occurrence of certain species and following their growth and decline, experts can see what pollutants are in the air, even if there is only sporadic exposure, as well as how serious the levels of pollution are.

An example of Foliose lichen growing on Willow

Lichens reproduce sexually or by shedding part of their structure (vegetatively).  Sexual reproduction involves spores, which are fungal and so don’t contain both halves of the symbiosis.  This means that the spore has to find a suitable species of algae to successfully reproduce – clearly a hit and miss process.  Vegetative reproduction is a more certain strategy because all parties to the symbiosis are present in the shed part of the lichen which then just has to land on an appropriate surface.  Many lichens use both strategies.

There’s no doubt that lichens are a strange and wonderful part of nature and it’s well worth looking around next time the weather allows to see how many different ones you can find.  But make sure that they are not mosses or liverworts because they are strangely different, or rather differently strange.

A Fruticose lichen growing on Willow