 |
| Teeny vole pelt |
Saturday, 21 February 2015
Latest stuff
Taxidermy reprise: here's a lady stoat completed this week, carrying a wee field vole which was found along with the stoat when it was caught (in a legal, lethal spring trap, though not by me).
If you'd like to see more you can head over to Stuff Stef Stuffs facebook page :)
Wednesday, 4 February 2015
Build a little worm house in your gut!
I have, in my time kick sampling, come across more than a few amphipods of the Gammarus pulex variety with bright orange patches showing through the side of their body, and have never known what they were - UNTIL NOW!
Through the magic of learning (which is fun by the way) in the form of lectures on parasite biology at university, I am now excited to share that these orangey bits are actually internal parasites! Going by the beautifully unwieldy name Pomphorhynchus laevis, the eggs of these acanthocephalan (spiny headed) worms are eaten by, and make their way into the gut of unsuspecting Gammarids (freshwater shrimp). What is particularly interesting about these parasites is that they can change the behaviour of Gammarus to increase their chances of making their way to their definitive host - a fish.
It has been shown that the bright colouration of the infective stage of Pomphorhynchus laevis is more easily spotted by fish such as trout and three-spined stickleback, the natural predators of Gammarus in streams and rivers. The parasite also changes the normal behaviour of the amphipod, causing it to be less sensitive to light which results in it spending more time in the open, or against light coloured gravel. It may also alter its sense of smell, making it unable to detect the scent of predators and flee. This makes them 'sitting ducks' so that hungry hunting fish can easily gobble them up!
You might think this is bad news for the parasite, when it is actually exactly what it wants as it ends up in the gut of its ultimate host where it is able to reproduce, release eggs which are expelled in the fish's faeces and start the cycle all over again. Some parasite species have extremely complicated life histories, going through many life stages in different forms and enduring exposure to different environments. For me it's a marvel how intimately parasites and their hosts have co-evolved over millions of years: developing adaptations to their host's immune system to avoid detection and death, ensuring that the next generation is spread to where the intermediate host will be, and also in some cases altering their intermediate host's behaviour in order to get where they need to be for the next life stage.
Of course it can be bad news for the infected fish if it ends up with too many hangers on inside its gut! A heavy load of spiny headed worms can reduce the weight and condition of the fish host and eventually lead to death.
Ahem. Well it's not all doom and gloom, our hook-headed pal has enabled some cool strides to be made in healing wounds. The hooks have inspired a micro needle design which can be used to attach skin grafts which are less damaging and more secure than conventional surgical staples. Also other parasites are being used in trials to treat autoimmune disease such as MS.
Huzzah for parasites!
Oh and tiny bit of self-promotion - you can get my blog posts delivered right to your email by signing up via the box on the top right hand side, and if you like sporadic nature and taxidermy updates and links you can subscribe to my Twitter feed! :)
 |
| Gammarus pulex showing infection with Pomphorhynchus laevis. |
Through the magic of learning (which is fun by the way) in the form of lectures on parasite biology at university, I am now excited to share that these orangey bits are actually internal parasites! Going by the beautifully unwieldy name Pomphorhynchus laevis, the eggs of these acanthocephalan (spiny headed) worms are eaten by, and make their way into the gut of unsuspecting Gammarids (freshwater shrimp). What is particularly interesting about these parasites is that they can change the behaviour of Gammarus to increase their chances of making their way to their definitive host - a fish.
It has been shown that the bright colouration of the infective stage of Pomphorhynchus laevis is more easily spotted by fish such as trout and three-spined stickleback, the natural predators of Gammarus in streams and rivers. The parasite also changes the normal behaviour of the amphipod, causing it to be less sensitive to light which results in it spending more time in the open, or against light coloured gravel. It may also alter its sense of smell, making it unable to detect the scent of predators and flee. This makes them 'sitting ducks' so that hungry hunting fish can easily gobble them up!
You might think this is bad news for the parasite, when it is actually exactly what it wants as it ends up in the gut of its ultimate host where it is able to reproduce, release eggs which are expelled in the fish's faeces and start the cycle all over again. Some parasite species have extremely complicated life histories, going through many life stages in different forms and enduring exposure to different environments. For me it's a marvel how intimately parasites and their hosts have co-evolved over millions of years: developing adaptations to their host's immune system to avoid detection and death, ensuring that the next generation is spread to where the intermediate host will be, and also in some cases altering their intermediate host's behaviour in order to get where they need to be for the next life stage.
 |
| A scary acanthocephalan worm (From http://www.carlsbergfondet.dk/~/media/Images/Forskerartikler/torskens%20spaende%20indre%20liv/lille%20illustration_version%201.ashx) |
Of course it can be bad news for the infected fish if it ends up with too many hangers on inside its gut! A heavy load of spiny headed worms can reduce the weight and condition of the fish host and eventually lead to death.
Ahem. Well it's not all doom and gloom, our hook-headed pal has enabled some cool strides to be made in healing wounds. The hooks have inspired a micro needle design which can be used to attach skin grafts which are less damaging and more secure than conventional surgical staples. Also other parasites are being used in trials to treat autoimmune disease such as MS.
Huzzah for parasites!
Oh and tiny bit of self-promotion - you can get my blog posts delivered right to your email by signing up via the box on the top right hand side, and if you like sporadic nature and taxidermy updates and links you can subscribe to my Twitter feed! :)
Subscribe to:
Posts (Atom)