Nature – Page 7 – Enviro-Mentalist

I learned today that Iachnis Io is more than just a pretty face

Thanks to Radio 4 and Butterfly Conservation’s Richard Fox. I am talking about the peacock butterfly, one of the four butterflies that overwinter in the UK and, along with the Small Tortoiseshell, the Peacock is the one you might come across in your garage or shed. (In case you are interested the other two butterflies are the Brimstone and Comma, both of which spend the winter in vegetation disguised as leaves.)

Apparently about half of the adult butterflies overwintering (they go dormant rather than hibernate) are predated and don’t make it through to spring. But, the peacock increases its chances threefold. Firstly the outside of their wings is dark, almost black making them difficult to see in the dark places they find for winter. In daylight their bright markings are thought to resemble eyes and either put off predators or cause them to attack the wings, away from their body. When they are attacked they flap their wings making quite a lot of noise (you can clearly hear them in the summer when they are feeding in the garden).

All these are things that I already knew about, but what I didn’t know is just how effective the defence mechanisms of the peacock are. Their bright colours and eye patterns just don’t help when their predators, often bats and mice, are usually looking for food in the dark. However, the clicking of their wings has been demonstrated to scare off mice and bats – after a close encounter with a predator the butterflies tend to move to somewhere safer to spend the winter. However, even more amazing, when they are out in the sunshine, not only do the bright colours and eyes help them see off predators such as blue tits, but they have apparently been shown to scare birds as large as chickens causing them to start making the same alarm calls as when they come across predators such as foxes.

I wonder what the chicken sees and thinks it has found? So, when you next see a peacock butterfly, don’t underestimate it…

I learned today … about fairy rings

which is quite a coincidence as we were discussing this very topic at the weekend, except at that point I didn’t realise what they were. If you see a circle (or circles) of lush grass or indeed dead grass, then that is a fairy ring.

These are caused by fungus growing underground – later in the year you might see the fruiting bodies, aka mushrooms. If the grass is much greener and thicker that’s because the mycelium (the underground bit equivalent to plant roots) is adding nutrients, if it is dead grass then the the fungus is damaging the plant roots. Each fairy ring is caused by a single fungus.

The rings are thought to start from a single spore that grows outwards until it reaches a certain size (around a metre) after which they run out of nutrients in the centre and start to form a ring, with nutrients passed around the ring to the point where they are needed. If the ring hits an obstacle such as stone the bit by the stone will die and the rest will grow around it. However, if it hits a larger obstacle such as a path it will stop growing and die. There were many reasons postulated for this, but it was discovered that the fungi are very polar and grow in one direction only, therefore if the is blocked they can’t grow anywhere else and therefore run out of nutrients. If they run into another fairy ring they compete with each other and both die! Despite this there are records of some fairy rings that are over 100 years old. According to one article I read there is a fairy ring in France that’s 600m in diameter and thought to be over 700 years old.

Fairy rings are also found in woodlands where they are known as tethered fairy rings as the mycelium are attached to the tree roots. The fungi gives the tree water and mineral nutrients such as nitrogen that it extracts from the soil and in return gets sugars from the tree. The mycelium are often seen in borders where they look like a mould on things like bark chips. In fact, fungi are one of natures great recyclers, being one of the few organisms that can break down lignin from trees due to the complex enzymes they contain.

Although fungi are very diverse; there are around 5 million species worldwide compared with 400,000 plant species, in the UK there are about 60 species that form fairy rings.

As can be gathered from the name fairy ring, there is a lot of folklore associated worldwide with these mushroom manifestations, worryingly enough the legends seem to have continued into the twentieth century. I won’t go into details, but suffice it to say it involves fairies and dancing and having to do all sorts of superstitious things such as running round the ring nine times with your cap on back to front if you find yourself in one of these rings.

I learned today … that a new type of bee has found its way to the UK

OK, two bee posts in two days, but this was the most interesting thing I learned today (apart from the fact that potassium permanganate is used to treat weeping skin blisters as a last resort) whilst listening to a Radio 4 podcast.

First seen in 2001 the Ivy Bee ( Colletes hederae )is slowly progressing up the British Isles as shown on the survey map. These bees start to fly around the end of August and have around a six week flight window coinciding with the flowering period of ivy. Although I haven’t seen one they apparently look like furry ginger wasps.

As with many solitary bees these dig a hole in the ground in which to lay their eggs. One pair will have around 10 offspring with up to 18 in a good year. In order to make sure the larva can survive for 10 to 11 months underground they provision the chamber where the egg is laid with up to 3million grains of pollen and nectar – this takes about 6 trips for each chamber – quite a task if you only live for about three weeks!

Although these bees are doing well – there is no need to worry – as with other bees, the males don’t sting and the females are very docile. As they have recently evolved they don’t yet have any predators here that have evolved with them and, as they don’t appear to pose any threat to native insects, let’s hope that they continue to flourish. I’ll be setting a reminder in my calendar to look for them next September. Looking at photos of them that I have found around the inter web I am fairly hopeful that I might recognise one if I see it. I have included a photo below from Wikipedia taken by Hectonichus – maybe ginger humbugs was a good description!

Today I learned … that not all bees collect pollen on their legs.

I already knew about the existence of cuckoo bees. These are bees that lay their eggs in the already provisioned nests of pollen collecting bees so that they don’t have to bother collecting pollen themselves. This means that they don’t have the hairy pollen baskets on their legs. This is one way of differentiating them from the hosts that they have evolved to mimic. However, an interesting article by Mike Edwards in the excellent British Wildlife Magazine gave me an insight into different types of bees and why their efficiency at pollinating plants varies so much.

The standard belief is that there is a mutually beneficial relationship between plants and pollinators whereby plants provide nectar as a foodstuff for the pollinating insect. In turn the bee moves pollen from the male part of the flower to the female whilst collecting it to take back to the nest for their larvae. This article revealed that this only occurs with certain species and that in many cases the plant is robbed!

What I didn’t know before today is that some bees, such as this white faced bee, are almost hairless and eat the pollen and nectar they collect before flying back to the nest; therefore denying the flower its rightful pollination.

The best known bees are the honey bees and the bumble bees, however, I also learned today these are not very efficient pollinators. In some cases these bees manage to get the nectar and avoid the reproductive parts of the flower and therefore don’t pollinate it at all. However, even if they do collect the pollen in the baskets on their legs, they need to wet it with nectar so that it doesn’t fall out. This means that the pollen isn’t readily transferred to the female part of the flower. Honey and bumble bees are, in effect, pollen robbers!

Whilst googling cuckoo bees for this short article I also came across this cool picture on Wikipedia. A cuckoo bee asleep, using its mandibles to hold on – what a fantastic shot! Until today I didn’t realise that bees did this!

Hawk-moths

For a while I have been thinking about getting a moth trap, but something about it just seems a bit mean. Moths don’t live for long and to keep them trapped for a night, especially when there are so many other hazards awaiting them just seems, well, wrong. However, this doesn’t mean that I don’t get to see some of the UK’s most spectacular moths.

Moths seem generally unloved and forgotten about by the general public, especially when compared to their butterfly cousins (I say cousins, but really there is little difference between a moth and a butterfly). I think that butterfly PR is helped by the fact that they fly during the day, whereas there are only a relatively small number of day flying moths. Or perhaps it is because there are only around 60 UK butterflies (and some of those are seen in only a few places in the British Isles) whereas there are a few hundred moth types – much more confusing.

It’s really only in the last few months that I have taken much of an interest in moths – the aforementioned butterflies taking my attention for the reasons outlined. However, the door to my office block seems to have been attracting some particularly distinctive moths in the last month – so distinctive that even a complete beginner like myself has been able to identify them with the help of a book and the interweb. It took me a while to work out why they were there, but then it occurred to me – there is a security light on the wall opposite which is obviously attracting them to the white wall. Fortunately they all chose areas to sit that made them easy to photograph, thus aiding identification. So I did, and the results are below:

The Lime Hawk-moth (mimas tiliae) was our first visitor and stayed in the same spot for a couple of days. They apparently have a couple of colour forms – one being much more green than this one. Like many of the hawk moths they are quite common, but this is the first one that I have spotted. Just as with butterflies, moths tend to hang out in places that contain the food plant of their larvae. As the name suggests, Lime Hawkmoth larvae feed on limes, but also other deciduous trees such as birch, alder and elm.

Next on the wall was a Privet Hawk-moth (sphinx ligustri) – a really big moth (the largest UK moth) – the wingspan can be up to 12cm across. This is a quite distinctive moth whose larvae feed on, yes, you’ve guessed it, privet, but also lilac and ash. Although these are also apparently fairly common I feel quite lucky to have seen it as they are only on the wing for a short time during July and August. Although this moth is pretty spectacular, the caterpillars are apparently even more impressive – no photos yet as I haven’t been able to find one.

The final hawkmoth to make an appearance turned up today and even stayed for the day despite the rain trying to batter it into submission. This is the Poplar Hawk-moth (loathoe populi) a smaller moth than the previous two, but still pretty impressive. It is one of the commonest hawk-moths in the uk; the larvae feeding on poplar, willow and aspen.

Although these moths are all hawk-moths they interestingly all seem to sit with their wings in different positions – the lime has them slightly outstretched, the privet had them held straight back and the poplar holds the back wings in front of the forewings.

I’ve now started looking for moths and will keep an update on the wildlife that I find at work – once you start looking it is amazing what you can find, even in a town centre location. It is making me think that maybe I should start measuring the biodiversity of the site …

Alder Fly

Every year I learn more and more about the natural world surrounding me. I find that for every creature that I learn to identify there are at least a dozen more waiting for me.

One of the advantages of working in my current location is that I can quickly get to the riverside and look for wildlife. In the sunny days of early May (which, looking at the grey sky seem a long time ago) I went looking for the first butterflies of the year. I saw a few, but they were disturbingly small in number. However, I did come across this fly which I had never noticed before and which is apparently fairly common and widespread.

Meet the alder fly (sialis lutaria):

Not very exciting you might think, and you would probably be right – the Wildlife Trust site describes them as sluggish and apparently dead alder flies are used as fishing bait. However, I have never noticed them before even though they were everywhere on the day I went for a walk. And, look at the detail in the wings. How can you fail to be impressed by that! Apparently, they have no connection with Alder other than being found near the edge of water (where the female lays about 200 eggs) which is where Alder is commonly found. Being sluggish they spend most of their time near the water where they hatched and where they live as carnivorous larvae for a couple of years before pupating into these adults. In case you are interested they are about 2 cm in length and there are several varieties which require expert identification to differentiate them.

On Red Admirals and Migration

A couple of weeks ago I wrote about the fantastic Red Admiral that I am hoping will be around and about as soon as the weather warms up. However, the reason that I was prompted to write about the butterfly was due to an interesting article that I read in the wonderfully informative British Wildlife magazine.

Whilst many nature lovers are aware of the satellite tagging that is now being done on all sorts of species, particularly the cuckoos and ospreys that have been tracked to Africa and back, you may not be aware that there are other ways to track the movement of species (particularly small, delicate ones such as butterflies).

Scientists have recently been investigating the levels of different isotopes of hydrogen found in the wings of Red Admirals across Europe. These are taken into the body of the butterfly when, as a caterpillar it does what caterpillars do and eats. Across Europe the normal foodstuff of a caterpillar will have different levels of these hydrogen isotopes. Comparison of these levels with non-migratory species of butterfly then allows scientists to tell where the butterfly spent its time as a caterpillar.

The results of the work were very interesting. Italian butterflies examined in autumn showed different isotope levels to non-migratory species. This indicated that the butterflies had developed in northern Europe and migrated south. Italian butterflies examined in the Spring had levels similar to those of local butterflies indicating that they were locally bred as a result of a winter breeding cycle and were not overwintering adults from further afield. In addition there were also some individuals that seemed to have migrated from further south in the Spring.

In Northern Europe the examination of butterflies in the Summer appears to suggest that they had migrated from central Europe, whilst those examined in the autumn appeared in the main to be more local, but with some migration still occurring from the south.

So, in conclusion it would appear that butterflies move north to breed in the Summer and then move south in the autumn to breed into the winter months. Will this change with the changing climate and, as previously noted, an increased propensity for adult Red Admirals to overwinter in some northern parts of Europe?

Snails – reasons to take a closer look.

Snails – curse of gardeners everywhere, something to try and remove at all costs, and dull, dull dull. As my mother would say, what use are they to anyone? Until recently I was of a similar opinion. I tried to remove them from the garden, tried to encourage hedgehogs in to help do away with them, watered nematodes around my crops (although I admit this was more to deal with slugs than snails) and generally wondered if there was anything good to say about them.
However, a few months ago I started my photography 366 project which involves taking a different photo each day. When out for an evening wander I came across lots of snails making their way across the footpath and spent far too long trying to take photos of them. I was struck by how varied they were and by the number of different colours and patterns. Being me I decided to do some research, the first port of call was my newly purchased copy of Bugs Britannica. This then led me to the internet and a new appreciation of these snails.
So, to start with, these are banded snails – there are brown lipped and white lipped varieties (although to add to the confusion young brown lipped snails have a white lip). To set the record straight, in common with many slugs, it appears that these snails feed mainly on decaying vegetation. So, although they will munch on my french beans, it seems that the garden snail is a bigger criminal.
The variation in colouration and banding pattern also means that they are one of the most genetically studied creatures around, that and the fact that they can be found pretty much everywhere. They come in three colour varieties – brown, pink and yellow and have varying amounts of banding – as illustrated in these photos. This was a basis for a huge online citizen science project carried out in 2009.
The basis of the project was to compare distributions of the yellow and brown snails and different amounts of banding – unbanded, mid-banding, lots of banding. Observations were made across Europe and compared to historical records. The reason behind the project was to see if the increase in temperature of 1.3oC in the latter half of the twentieth century had affected the distribution of the variations. This is because of the ‘albedo’ effect – which is a measure of the reflectivity of a surface. The theory was that as the climate got warmer there would be an increase in the number of yellow-shelled snails compared to the darker variants and an increase in the proportion of unbanded snails as they evolved to stay cooler.
So, what was the result. They separated out the results according to habitat – sand dunes, grassland, hedges and woodland. It was only in the sand dune areas that the proportion of yellow snails increased – in the other areas it would appear that there was sufficient shade and moisture that the increase in global temperature had no effect. In fact a higher proportion of yellow snails were found in the sand dunes compared to the brown and banded snails and there was a decrease in frequency of the yellow snails as the amount of shading available increased; the smallest proportion being found in woodlands.
With regards to the banding the conclusion was that the data was inconclusive! There is the potential that changes are linked to habitat and predation. As their main predator is the song thrush then changes in the distribution of the song thrush may have an effect. Changes in the habitat that are not easily captured by the survey data may also be responsible for changes. Other things may have an effect… It appears that the banded snail is retaining an element of mystery for further study.

Migrant Butterflies

When you think of migrant species, the word butterfly is not usually the first thing that pops into your head. Whilst many of us have seen pictures of the mass migrations of Monarch butterflies in America, you may not realise that many of the butterflies that we see in our gardens each year have flown in from Europe or Africa. (Although the recent coverage of the Painted Lady migrations on the fantastic Springwatch may have increased awareness of migratory butterflies.)

More surprising though is the fact that one of our commonest butterflies, the Red Admiral, is a migrant. To confuse things still further though, it is also in some cases being classed as a resident. Climate change and the warmer winters means that it is now able to survive winters as an adult in the south of the country (this includes Northamptonshire). Consequently it is often one of the first butterflies seen each year – often in January.

The Red Admiral is a striking and unmistakeable butterfly. Its Latin name is Vanessa Atalanta, named after the beautiful and athletic goddess Atalanta, a famous huntress. Atalanta tried to enlist with the argonauts but was turned down as Jason was worried about the presence of one woman on the ship. She would go to such lengths to avoid marriage that suitors were challenged to a race, those who lost, the penalty not being a sufficient deterrent, being put to death. She was eventually beaten after the love goddess Aphrodite took pity on a suitor and helped him distract Atalanta during the race.

The butterfly given her name can be seen throughout the year (although the first major migration occurs from mid-May to the end of June), in most habitats, throughout the country. It will visit many flowers, switching from one favourite to another as the summer progresses, moving onto fruit and then ivy blossom in the autumn. There would usually be a return migration in the autumn, but they are increasingly staying to overwinter in the south of England.

The food plant of the Red Admiral is the nettle, with the small, green egg laid on the upperside of a leaf. When this hatches, the caterpillar uses silk to form a tent from the leaf on which it hatched, and, as it grows it pulls in more leaves to its tent and eventually makes its chrysalis in the tent. After two and half weeks the black or yellow spiny caterpillar will emerge from its chrysalis as a stunning red, white and black butterfly.

Creating a buzz just Bee Cause

Friends of the Earth are hoping to create a bit of a buzz with their Bee Cause campaign. I attended a launch event in Northampton today – the aims of the campaign are to get those in power – specifically David Cameron, to acknowledge that the government needs to adopt and implement a bee action plan. The launch event included a couple of talks about pollinators and their habitats.

Why are bees important? Just to clear up a misconception, it is not just bees that are important it is all of natures pollinators – insects, animals and birds – even some lizards are important pollinators elsewhere in the world. Across the world 87% of the estimated 308,000 plant species are pollinated by insects and other fauna.

There has been a lot of coverage about the collapse of honey bee populations across the world and lots of speculation about the reasons. However, this is not a new phenomenon and since the 1800s the UK has lost 23 species of bee and 18 species of butterflies. More recently there has been a 75% decline in moths since the 1970s and a 25% decline in hoverflies since the 1980s. So, it would appear that the recent problems with honey bees are only the latest in a long line of declines. Whilst there are lots of reasons for this, the overriding issue has to be loss of suitable habitat caused by urban expansion and the intensification of agriculture and removal of woodlands and hedgerows. Indeed Northamptonshire holds the dubious distinction of having lost more species of wildflowers than any other county. Not something to be proud of.

So, the Bee Cause campaign aims to raise awareness of this problem and get people taking action. I’ll be writing some more posts outlining what you can do to help our pollinators in the coming weeks. In the meantime, if you are interested in getting involved in the campaign there is a lot of information on the FoE website. Alternatively, if you are in the Daventry area and would like to help, give me a shout and we can work together to make Daventry a bee-friendly place.