Red squirrels in British Isles showing immunity to disease
Apr 18, 2015 20:09:43 GMT -5
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Post by Marches on Apr 18, 2015 20:09:43 GMT -5
I know this is off topic, but it is interesting nevertheless. Makes one wonder as to whether plants such as Vitis vinifera and American chestnuts can develop some resistance over time.
Thought you guys would be interested in this sort of thing, I know I certainly am.
In the UK the introduced Eastern Grey Squirrel from America was introduced. It led to the decline of the native Eurasian red squirrel which has been in massive retreat mostly to Scotland and some isolated outposts in England and Wales.
The cause is thought to be a disease the greys pass on that has little affect to them (para pox virus) but is deadly to reds (a la phylloxera in Vitis vinifera).
But recently two interesting things have been found. Individuals which are seemingly immune have been found in England and an unlikely ally in a predator (pine marten) has been found in Ireland.
In the pine marten case, the study found that grey squirrels were actually retreating from areas where Pine martens were present. Apparently the reds that co-evolved with the predator can avoid it better whereas not only is the grey an easier target spending more time on the ground gathering food, but the study actually found the greys in such areas were malnourished, leading them to believe the greys are basically terrified of the predator, spend less time feeding as a result and starve. Thus the host of the disease doesn't get to the west of Ireland.
Why haven't pine martens done the same in England? Because they're virtually extinct here due to hunting. Game keepers disliking them ensured they're now mostly restricted to Scotland, pretty much the same areas where red squirrels thrive.
So hopefully by tracking the immune individuals and establishing breeding programmes and helping the pine marten reestablish the reds can spread back across much of their range.
Pine martens are slowly entering England again with sittings in the far north near Scotland. Pine martens might help explain why grey squirrels in Italy haven't spread north of the Alps yet (which would be a disaster - the reds range is from Ireland to the Russian far East as far as Sakhalin and Vladivostok).
I doubt greys will ever die out if reds reestablished. Greys are like pigeons or rats in that they're much less picky in their feeding habits and thus very successful here, I sometimes wonder if they're better adapted to the UK than the native reds. They're very successful in urban areas in any case where pine martens if they reestablish would be unlikely to colonise, and reds can't outcompete them. In any case, pine martens will take decades to colonise England even if they're left to do so, so there won't be a massive boom in reds any time soon.
But it's encouraging. Be nice to see areas of reds and areas of greys or both species eventually coexisting in my life time hopefully.
Makes me hopeful about other less resistant species such as vinifera and American chestnuts.
Squirrels and pine martens -
www.theguardian.com/environment/2013/feb/22/red-squirrel-pine-marten-survival
Red squirrel immunity -
www.theguardian.com/environment/2013/nov/22/red-squirrels-poxvirus-resistance
Red squirrel range change map. Note most of those areas have coniferous forests and pine martens -
rsst.org.uk/wp-content/uploads/2012/07/squirrel-maps.jpg
Thought you guys would be interested in this sort of thing, I know I certainly am.
In the UK the introduced Eastern Grey Squirrel from America was introduced. It led to the decline of the native Eurasian red squirrel which has been in massive retreat mostly to Scotland and some isolated outposts in England and Wales.
The cause is thought to be a disease the greys pass on that has little affect to them (para pox virus) but is deadly to reds (a la phylloxera in Vitis vinifera).
But recently two interesting things have been found. Individuals which are seemingly immune have been found in England and an unlikely ally in a predator (pine marten) has been found in Ireland.
In the pine marten case, the study found that grey squirrels were actually retreating from areas where Pine martens were present. Apparently the reds that co-evolved with the predator can avoid it better whereas not only is the grey an easier target spending more time on the ground gathering food, but the study actually found the greys in such areas were malnourished, leading them to believe the greys are basically terrified of the predator, spend less time feeding as a result and starve. Thus the host of the disease doesn't get to the west of Ireland.
Why haven't pine martens done the same in England? Because they're virtually extinct here due to hunting. Game keepers disliking them ensured they're now mostly restricted to Scotland, pretty much the same areas where red squirrels thrive.
So hopefully by tracking the immune individuals and establishing breeding programmes and helping the pine marten reestablish the reds can spread back across much of their range.
Pine martens are slowly entering England again with sittings in the far north near Scotland. Pine martens might help explain why grey squirrels in Italy haven't spread north of the Alps yet (which would be a disaster - the reds range is from Ireland to the Russian far East as far as Sakhalin and Vladivostok).
I doubt greys will ever die out if reds reestablished. Greys are like pigeons or rats in that they're much less picky in their feeding habits and thus very successful here, I sometimes wonder if they're better adapted to the UK than the native reds. They're very successful in urban areas in any case where pine martens if they reestablish would be unlikely to colonise, and reds can't outcompete them. In any case, pine martens will take decades to colonise England even if they're left to do so, so there won't be a massive boom in reds any time soon.
But it's encouraging. Be nice to see areas of reds and areas of greys or both species eventually coexisting in my life time hopefully.
Makes me hopeful about other less resistant species such as vinifera and American chestnuts.
Squirrels and pine martens -
www.theguardian.com/environment/2013/feb/22/red-squirrel-pine-marten-survival
Red squirrel immunity -
www.theguardian.com/environment/2013/nov/22/red-squirrels-poxvirus-resistance
Red squirrel range change map. Note most of those areas have coniferous forests and pine martens -
rsst.org.uk/wp-content/uploads/2012/07/squirrel-maps.jpg