Posts Tagged ‘autumnwatch’

Autumnwatch #4: The Comma: Is it a leaf? Is it a form of punctuation? No, it’s a Butterfly!

IMG_0465  Another butterfly that you might catch flying on these sunny Autumn days is the Comma (Polygonia c-album). A member of Nymphalidae, it is drawn to late autumn flowers and fallen fruit. It’s a very interesting species for a number of reasons. Firstly, look at that camouflage! The whole wing shape of the Comma has evolved to look like the shape of a dead leaf; when it closes its wings, all you see are the crinkled brown undersides, a perfect illusion. Even the attractive uppersides are an aesthetically seasonal mix of orange and brown.IMG_0407

GRAMMATICAL BUTTERFLIES?

So why the unusual name? Well, if you look closely in the picture below, you can see a little white mark on the underside of the wings that looks like… a comma. Bizarrely enough, the butterfly has a North American relative called ‘The Question Mark’ that has a white mark that looks a bit like…a question mark! (I challenge you to a cross-curricular link to this preparation for Mr Gove’s SPAG test!)

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Spot the comma…

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And spot the question mark on its North American friend..
(Picture source: Fine Art America)

FLUCTUATING POPULATIONS

The Comma is now quite a frequent sight across Britain, but once the situation was very different. At the turn of the century, numbers started a massive decline; by the 1920s there were only a few colonies left in Hereford and Worcestershire. Happily, things suddenly and inexplicably improved, and this species is one of the few butterfly success stories of recent years.

More info and photos here…http://www.ukbutterflies.co.uk/species.php?species=c-album

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AUTUMNWATCH #3: MAPLE OR SYCAMORE?

IMG_0677So then, on to identification of some common leaves… Today we’re tackling some species that belong in the same genus and are often confused: the Norway Maple and the sycamore.

In fact, our heading is really a trick question; these are both technically Maples, sharing the genus Acer. They are also relatively common, frequently planted in school grounds, and you are likely to come across them during your Autumn leaf searches.

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Norway Maple

The picture above shows a Norway Maple leaf on the left and a Sycamore leaf on the right. The main difference is that the Norway Maple has a significantly more jagged edge, and a glossier surface. In fact, although not the same species, it looks very similar to the Maple leaf on the Canadian flag. In looking at the full trees, Sycamores also tend to grow higher.

In Autumn, the leaves become much easier to tell apart. Norway Maple leaves are some of the first to change  colour, turning a blazing scarlet that illuminates streets, parks and woodlands. There’s a dark side to this beauty; actuall,y this red pigment is produced as a side-effect of something called allelopathy. This is the scientific name for a sneaky trick the tree has up its sleeve to fend off competition for resources from nearby trees. Norway maples produce and release chemicals to hinder the growth of nearby saplings. The blood-red pigments are merely a by-product of this.

Sycamore leaves never turn red. They usually go a blotchy green-yellow. This sample is also adorned with black spots; rather than a consequence of autrumn colour changes, this is actually a fungus that becomes an increasingly common sight. Although it doesn’t look so nice, and the trees probably aren’t too happy about it, spotting this is actually a positive sign. The fungus can only flourish in very clean air, so it’s a great environmental indicator for air quality.

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Sycamore

(OPAL have some tree health surveys based around this that you can do in your school grounds).

So, in summary; sycamores grow taller, and their leaves turn yellow. Norway maples turn red, are a bit selfish, and have glossier leaves. Both trees share the ‘helicopter’ keys beloved by children and so useful when teaching seed dispersal, so it;s worth getting to know their names.

Before we go, there’s one more maple tree to be mentioned: the Field Maple is smaller and less showy than both of the others. Sometimes it is used as a hedging plant. It’s leaves are smaller and more rounded, and turn yellow rather than red. It too produces ‘helicopter’ keys, but they are much smaller.

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Field Maple

Primary Scientists Autumnwatch #1: The Small Tortoiseshell

Well, Autumn hasn’t officially started yet, but here we go! These first few weeks of the Autumn term are interesting ones, the interface between the fading summer and the oncoming crisp golden-ness of October making for some great wildlife-watching  opportunities.

Already the days are starting to have that September chill in the air, and soon the numbers of insects will be diminishing. There are several species of butterfly still to be seen ‘on the wing’ into September and October, and in fact these are some of our most colourful and familiar. Today we are highlighting a well-known and popular species, the Small Tortoiseshell.

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THE SMALL TORTOISESHELL

Aglais urticae

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One of the most colourful species of butterfly to be seen in Britain, the Small Tortoisheshell is widespread throughout the country. Partly, this is due to the wide availability of its foodplant, the common stinging nettle. However, in recent years it has become significantly less common, with recent studies citing as high as 52% decreases in some areas. There is some speculation that this is because of the spread of a parasitic fly, Sturmia bella, whose eggs are laid on nettle leaves and then ingested by caterpillars. You can read more about a study into this here.

On the bright side, the butterfly seems to have enjoyed a good summer this year, no doubt boosted by our scorching July!

There are two broods of the species each year. Adults hatch in July and August, and can survive not only our Autumn, but winter as well. Although you probablyt won’t see them, they are one of the few species that hibernate, in sheds, outbuildings and eaves of buildings. On warm February days you might be startled to find one of these overwintering specimens flying around your house, having woken prematurely!

The overwintered Tortoiseshells are some of the first butterflies to be seen each year, and breed again in the Spring.

CLASSROOM POTENTIAL

Small Tortoiseshell caterpillars - coming to a classroom near you?

Small Tortoiseshell caterpillars – coming to a classroom near you?

The Small Tortoishell is a great species to use in class supporting life cycles. Caterpillars are easily bred in captivity, and fresh nettles are easy to find to top up their food supply; it’s a great one to rear in your classroom, and the butterflies can be released anywhere. The organisation WorldWideButterflies provides special school rearing packs (as well as lots more) here, which are available from September. Obviously, this sort of project provides lots of great learning opportunities. As well as purely Science objectives, you could work in literacy themes of explanations (the life cycle), instructions (how to care for the caterpillars), as well as poetry, descriptive writing and so forth. As well as learning opportunities, there is the potential to help boost wild stocks of a species not as common as it was.

EXTINCT RELATIVE

Did you know that the Small Tortoiseshell has a much rarer relative?

The Large Tortoiseshell. Picture source: Wikipedia

The Large Tortoiseshell. Picture source: Wikipedia

The Large Tortoisheshell Nymphalis polychloris, is superficially similar, but a paler orange and, you guessed it, larger. It once lived alongside it’s smaller cousin in the U.K., but has been declared extinct here for a number of years. Partly this was due to its more specialised needs; the caterpillars fed on elm trees, much less common than nettles. It hasn’t been seen for certain since the 1950s, although there are hopes for a comeback in the Isle of Wight.

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