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Monthly Archives: August 2011

Summer Wildlife Encounters

A host of unusual loveliness

Where to begin? Firstly, a quick apology for the hiatus of last week, a sheer volume of events through the week and the previous three weekends meant that I was unable to meet the copy deadline and sadly missed our weekly wildlife rendez-vous.

However, the upshot of all these events is an amazing collection of unusual wildlife sightings, all shared with families and friends throughout the district. And the good news for me is that many of the participants had smart phones or cameras (how charmingly retro) with them and happily shared the picture prizes.

Most recently a grey and mizzly morning rockpooling at Sidmouth’s Jacobs Ladder beach turned up not one, not two, or indeed three, but four amazing arthropods. Sea spiders. I remember first encountering these gangly little creatures in a marine zoology unit of my degree course, they are so strange that once met they will never been forgotten.

Easily overlooked as a piece of algae, sea spiders are weird creatures!

Despite being called spiders, and belonging to the arthropod group, these animals are not arachnids and their eight-legged resemblance to the terrestrial and aquatic true spiders is purely chance. The odd thing about sea spiders is that they have no respiratory system, instead they make use of their high surface area to volume ratio to allow passive gaseous exchange to provide oxygen. This means that they must have extremely clean skin, and indeed their exoskeleton is unusual in being sterile, something which many scientists are interested in studying; being able to find out how they maintain bacteria-free skin in the sea could have huge benefits for shipping.

Sea spiders in our waters tend to be found in rockpools, hanging on to tiny tree-like algae, on which they hunt for tiny anemone prey. However, they are not found often, in seven years rockpooling the East Devon coast with schools and families, I have only found one before now. On thursday morning we found four!

Last weekend was Escot’s annual “Messing about on the River” event, a feast of old-fashioned netting for sticklebacks and eels, while Alan Bruford indulges in a spot of gold panning with families. We smile and nod enthusiastically, but know this is merely a ruse to satisfy Mr B’s appetite for getting muddy!

A good haul of fish were caught by Jim and myself, including young brown trout, which the river Tale has been praised for this year. Amongst the bullheads, stone loaches, sticklebacks and eels were two fish which looked like eels. On closer inspection they had no eyes, pores rather than gills and no complex fins. These weren’t fish, but the larvae of a fishy-type animal called a Lamprey; these were ammocoete larvae!

The blind worm-like creature is the larva of a lamprey, an Amocoete

Lamprey were once common and prized for the table, indeed King Henry I was so fond of the meal he contracted food poisoning ascribed to consuming “a surfeit of lampreys”. They have become far less common since 1069, though and this was the first time I had seen one of these animals! Lamprey are put in a group alongside fish, rather than being a true fish, and apart from having a free-living large larva they are very different to fish in a number of ways.

Firstly they have no jaw, just a round mouth covered in amazing rows of sharp teeth. They live for many years as larvae, before heading off to sea to grow into adulthood. They are the most primitive vertebrate and all animals with backbones are thought to have evolved from a lamprey common ancestor, which means us!

Finally the previous weekend saw a mammoth natural history survey of the Axe Estuary Wetlands, with a variety of experts assisting us with a BioBlitz! The Field Studies Base provided our HQ for the day, while experts spent the day rootling and tootling about the wetlands identifying their particular groups.

We have reams of records now to show for the efforts, all of which will be added to what we know about the site and help in our efforts to improve them for biodiversity into the future. A first for Devon in 60 years was discovered with the discovery of a larval 13-spot ladybird by ladybird expert Richard Comont. This rare ladybird dies out in Britain each year and is thought to recolonise from the continent. A breeding colony in Stafford Marsh would indeed be a turn up for the books!

The amazingly exotic puss moth caterpillar (photo: Stu Derrick)

Richard also found the poster child for the day, by discovering a fabulous puss moth caterpillar in the accompanying photo. This larva of the white fluffy puss moth (puss as in kitten rather than putrified mucus!) looks like it should live in the tropics, and it is seldom seen here despite being quite common.

The thing is, even though they are lime green with a pink face, purple back and two red tendril tails, they spend their time feeding in willow, sallow or poplar trees and are normally well out of sight. These caterpillars were feeding on a willow sculpted maze constructed on the wetlands and played amongst by hundreds of children this year. All the while we were unaware of the presence of this wonderful caterpillar. After we spotted these two the maze was given further scrutiny whereupon poplar hawkmoth and eyed hawkmoth caterpillars were found too!

Its amazing what is there, living under your nose, if you just stop a while to look!

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Posted by on August 25, 2011 in Insects, Marine

 

Thanks to Mr Fry…

..whose tweet drew my attention to this interesting story.

Anyone who has spent any time scruitinising a bramble bush at this time of year will be familiar with the snake-like trace on the leaf surface. These labyrinth squiggles are the tunnels of the serpentine leaf miner caterpillar, which eats the leaf from within the leaf, before pupating and emerging as a tiny moth.

The serpentine leaf miner is a native moth, which has successfully co-existed with bramble for millennia, anyone clearing an overgrown garden will testify to how pioneering the plant is! However, a new leaf miner has arrived on our shores and scientists at the University of Bristol are appealing for help in tracking its spread.

The Horse Chestnut leaf miner is a rather gorgeous moth which was first recorded in London as recently as 2002. It may be attractive, but it is capable of causing considerable damage to conker trees as its mines within the leaf are large and are so profuse that they severely restrict the tree’s ability to photosynthesize.

The Horse Chestnut leaf miner - A beautiful, but worrying new moth

As the photo shows, the caterpillars hatch from the eggs and eat the spongy layer of the leaf, known as the mesophyl, safely tucked away from harm protected by the upper and lower leaf membranes. This larval safety means that the moth has been able to spread at an incredible rate, from the first records from the Capital in 2002 the moth is now know from Cornwall to Kent; Hampshire to the Midlands.

The Universities of Bristol and Hull have teamed up to investigate the movement of this new species and the scientists have set us a challenge. Citizen science is all the rage at the moment, but this time its gone digital!

The recognisable damage to a horse chestnut leaf caused by the miner moth

If you have a smart phone, be it iPhone or Android, you can download a free ap (as I have) which will help you to submit recordings of horse chestnut miners as and when you find them. The ap will allow you to snap a photo of the leaf and send it to the project complete with all the details the boffins need. What a fabulous use of technology!

This initiative is causing quite a stir. My attention to the project came via Stephen Fry, albeit on Twitter! Twitter is fast becoming the preferred means of sharing information between interested individuals, as you can tailor your feed to only show you people or organisations you are interested in. I was logged in to my account when a link popped up from Mr Fry to the University of Brisol website, I duly opened the page, read the report and downloaded the ap. Hey-presto, another leaf watcher enrolled with hopefully a few more on the way!

I’ll retweet the link on the East Devon District Council twitter account @WildEastDevon so if you follow us, you’ll see what I am talking about in due course.

The ap can be downloaded from here and Stephen Fry can be found on Twitter at @stephenfry – give him a follow and tell him @TheTiercel says “Hi!”

Stoatally different

A lot of conservation focus is put upon control; be it habitat or species. The East Devon Water Vole Project successfully reduced mink populations on the Axe and Otter catchments to such a level that we were able to successfully reintroduce Water Voles on to the lower Axe.

These endeering little mammals have proved incredibly popular, as they are seen to within a few metres, feeding in the ditches around Black Hole Marsh.  I recently received a number of concerned reports that a stoat had been seen mooching about (if it is possible for something so agile to ‘mooch’) the ditches in which the voles have taken up residence. Subsequently the voles are a lot harder to spot!

People are worried that the stoat has eaten the voles and, as we got rid of mink for doing exactly the same, we ought to turn our attentions on the stoat. However, this ginger predator is an entirely different kettle of fish and its all to do with evolution.

Stoats and water voles have co-existed successfully in Britain because the stoat is unable to swim and therefor the only kills it can make are when it sneaks up on a Water Vole while it is feeding on the bank. Mink on the other hand only appeared here in the 1950s escaping from fur farms, and are able to follow a water vole into the sanctuary of its burrow as well as being excellent swimmers. A single mink can therefor consume an entire population of water voles; they have nowhere to hide.

So, while it might be a bit upsetting that the voles have put their heads down for a while, it would not be right to intervene in this native predator-prey relationship. Its not death that us conservationists attempt to address, its species loss; a subtle but very important distinction.

 
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Posted by on August 5, 2011 in Insects