August 2014

Peppered moth - Biston betularia

National Moth Night turned out to be somewhat damp and so Trevor and I postponed the moth trapping for a week or so and there were plenty of moths out there, including some magnificent hawk-moths, as well as some very much smaller micro-moths that are much more difficult to identify.  One of the difficulties in identifying moths is that some species have several different colour forms, the most famous example of this being the Peppered moth (Biston betularia).  We have Peppered moths in the moth trap quite regularly.  The most common form of this moth is white and it is ‘peppered’ with black dots, but it also has a completely black form.   Originally, most of the moths were the white form, with relatively few of the black form (less than 1%).  But in the nineteenth and early twentieth centuries, it was noticed that most of the moths were of the black form, in fact, by 1895 more than 95% were the black form.  This was because industrial and urban pollution killed the pale coloured lichens, and soot made the trees where they rest during the day, black.  This meant that predators could easily pick out the white form, but the black form was hidden against the black trunk.  Now that we have the Clean Air Act, the lichens have returned and the trees are no longer sooty, so the white form is more common – evolution in action indeed.

Field Grasshopper - Chorthippus brunneus

But moths are not the only creatures with different colour forms.  I recently photographed a pink grasshopper near Dungeness.  I got quite excited when I got back home and read that the pink form of the Meadow Grasshopper (Chorthippus parallelus) was quite a rarity when the normal colour form was green, or green and brown.  When I read a bit further though, I found that some experts think that all the nymphs of the Meadow Grasshopper are pink and that only the females in rare cases retain the pink colour to adulthood.  (Nymphs are the non-flying juvenile form of grasshopper which doesn’t have the larval or caterpillar stage of other insects.)  So of course all I had to do to prove that I had a rarity was to see if the grasshopper I photographed was a nymph or an adult.  I checked and it was indeed an adult, but while I was checking it, I noticed that though it was an adult, it was an adult Field Grasshopper (Chorthippus brunneus).  When I looked up the Field Grasshopper, I found that rather than different colour forms it has a range of colours from buff through green to purple, and that pink wasn’t at all unusual.  Ah well, it’s still a very pretty insect.

Another colour variation you may see if you are anywhere near the Village Hall is a white squirrel.  This is not a different species, but a white form of the Grey Squirrel (Sciurus carolinensis).  There are two reasons why a grey squirrel may be white.  One is albinism, this occurs when the animal has a genetic mutation that makes it unable to produce melanin, which is the substance that gives skin and hair its colour.  The other reason is called leucism and it is where the animal has a normal gene that codes for different fur colours in the same way that we have a gene for blue or brown eyes.  Because the gene is recessive, both parents would have to be white for the offspring to be white.  If one parent was grey then all the offspring would be grey.  The difference between albinism and leucism is that albino squirrels have pink eyes, whereas in leucism they have normal black coloured eyes.  The one by the Village Hall has pink eyes, so it is an albino squirrel.  According to wildlife experts there is a one in 100,000 chance of a grey squirrel being born white.  I've been unable to find out who those experts are, or to find out how they came up with such a suspiciously round number, but it’s a remarkable sight and I’m indebted to Trevor Buttle for the great photograph.

Grey Squirrel - Sciurus carolinensis

July 2014

The house martins have finally settled down and there are two pairs apparently raising two broods of chicks in our eaves.  I say apparently because until the youngsters are big enough to poke their heads out of the nest, it’s hard to tell exactly what’s going on.  But we’ve found several eggshells below the nests and the adults are busy ferrying food into the nests.  Sadly this year, the swallows haven’t nested in the carport.  In fact, the number of swallows seems to be down this year.  I read an article by Bill Oddie in the BBC Wildlife magazine where he recounts his experience of a holiday in Cyprus in the 1980’s when he thought war had broken out due to the number of shotguns being fired.  It turns out that his holiday coincided with the start of the bird shooting season.  He visited again recently hoping that things had improved now that shooting birds was illegal.  It hadn’t.  It seems that people’s liking for ‘sport’ is stronger than the will to enforce the law.  I can’t understand people killing things for pleasure, especially if they are not going to eat their kill afterwards.  I hope that our swallows haven’t suffered that fate, but the evidence seems against it.

In our garden we have Water Figwort (Scrophularia auriculata).  I don’t know why we have Water Figwort as there is certainly no water there and it is in a particularly dry flowerbed.  Part of the reason that we have so much figwort now is that last year I let one Water Figwort flower and set seed.  The figwort has a very strange flower that looks more like something out of a Mickey Mouse cartoon than part of a plant.  In order to set seed, of course, the flower has to be pollinated, and unlike most flowers that get pollinated by bees or hoverflies, the figwort has developed a relationship with wasps.  One species of wasp in particular, the Tree Wasp (Dolichovespula sylvestris), seems to be the main pollinator of the figwort.  Tree Wasps, like many social wasps have a sweet tooth and will take sugar from many sources, from the jam in your picnic, through honeydew from aphids or their own larvae, to nectar from flowers.  However, wasps have very short tongues, probably because they have such large and strong jaws which they use to mash up their meatier prey.  This means that they can only take nectar from flowers that have very short pollen tubes such as figwort, gooseberry or ivy.

Flowers that have ‘wort’ at the end of their name usually had a medicinal use in the days before large pharmaceutical companies thought they could do better.  Of course some of the cures were less effective than others, and one thing that ancient herbalists used to determine which plant to use for which ailment was the Doctrine of Signatures.  Basically, the Doctrine of Signatures meant that plants that had features that resembled parts of the body were used to treat that part of the body, so that for example, Eyebright whose flowers were thought to resemble eyes, was used to treat eye infections.  The only other thing you need to know about Figwort is that fig is an ancient word for piles.  It was thought that the red flower buds and tubercles on the roots of Figwort resembled piles as well as the tubercles on the necks of sufferers of scrofula.  Scrofula was also thought to be cured by the touch of a king or queen, and became known as the King’s Evil as a result.  Scrofula also gives Figwort its scientific name – Scrophularia – as well as to the large family of plants in which it resides, the Scrophulariaceae, which also includes many diverse plants such as mulleins and toadflaxes.

Don’t forget that July 3-5 sees the celebration of National Moth Night (actually 3 nights) organized by Atropos and Butterfly Conservation.  Trevor Buttle and I will be running our moth traps on at least one of the nights, so if you want to see some interesting moths and don’t mind an early start, why not join us to examine the catch.  Send me an email (alan.kenworthy@virgin.net) or contact me through the editor, if you want to know more.

Water Figwort - Scrophularia auriculata

House Martin - Delichon urbica

Tree Wasp - Dolichovespula sylvestris