Large Blue butterfly by David Attenborough

[robin wood]

The story of the large blue butterfly is one which every conservationist should know and I have never heard it told better than by David Attenborough in his great "life stories" series. Available for 3 days online here. Worth ten minutes of anyone's time.

http://www.bbc.co.uk/programmes/b00krkgt

 

[hammock monkey]

Great stuff - thanks

 

[VirusKiller]

Worth ten minutes of anyone's time.

Absolutely. A fascinating story. Thanks.

 

[Nagual]

Wonderfully interesting, thanks for sharing it.

 

[robin wood]

The story is so interesting on so many levels.

The blue went into serious decline due to overzealous collectors, folk who on the one hand must have had a deep knowledge of and interest in nature and yet the rarer the butterflies got the more keen they were to catch a rarity.

Then the conservationists tried to manage the site of the last British population but due to incomplete knowledge of the complexities of the lifecycle the butterfly continued to decline and eventually went extinct in the UK.

To me there are two messages, one is that managing for just one species even a rare one is rarely a good idea and dramatic changes in management eg grazing regime should only be done with thorough understanding, long term continuity of management has tended to produce our more interesting sites.

The second message for me is that nature and the interconnectedness of everything is always far more complex than we could possibly imagine. The lifecycle of the large blue is so utterly incredible it makes me question evolution...how on earth do you get to that situation in simple evolutionary steps?

 

[Nagual]

The story is so interesting on so many levels.

The blue went into serious decline due to overzealous collectors, folk who on the one hand must have had a deep knowledge of and interest in nature and yet the rarer the butterflies got the more keen they were to catch a rarity.

Then the conservationists tried to manage the site of the last British population but due to incomplete knowledge of the complexities of the lifecycle the butterfly continued to decline and eventually went extinct in the UK.

To me there are two messages, one is that managing for just one species even a rare one is rarely a good idea and dramatic changes in management eg grazing regime should only be done with thorough understanding, long term continuity of management has tended to produce our more interesting sites.

The second message for me is that nature and the interconnectedness of everything is always far more complex than we could possibly imagine. The lifecycle of the large blue is so utterly incredible it makes me question evolution...how on earth do you get to that situation in simple evolutionary steps?

Aye, it reminds me of something I read somewhere ages ago, where someone found a rare plant / flower growing on a farmers field. All kinds of folks went up to investigate and told the farmer it was rare etc, and that he shouldn't spray that area with any sort of sprays or whatnot as this may kill the plant. This of course came to a shock to the farmer who had been happily spraying for decades. However they were adamant that it should stop, so he did. With in a few weeks the plants had been eaten by sheep, where as before they didn't like the spray on the plants so left it well alone..

 

[gregorach]

The lifecycle of the large blue is so utterly incredible it makes me question evolution...how on earth do you get to that situation in simple evolutionary steps?

Over a very long period of time.

And it's really no weirder than that of many other parasites. It's not like it involves multiple species, like tapeworms or the malaria parasite.

EDIT:
Oh, and what's really amazing is the wasp which parasitizes the Large Blue...

 

[robin wood]

Over a very long period of time.

And it's really no weirder than that of many other parasites. It's not like it involves multiple species, like tapeworms or the malaria parasite.

EDIT:
Oh, and what's really amazing is the wasp which parasitizes the Large Blue...

Indeed the wasp is amazing, that has to be a pretty small and dead end evolutionary niche.

Don't get me wrong I am not saying this bizarre situation didn't happen by evolution it is just very very difficult to see it happening. It's not like the tortoises with long necks surviving better on dry islands gradually breeding more with longer necks. I mean one day the caterpillars must have been doing fine munching leaves and the next they are exuding protective pheromones and munching ant larvae, it's a big jump in one go and I don't see how you get there in little steps.

 

[BigShot]

No matter who you listen to it's all just an argument of internal consistency without a solid basis of fact and some rather hefty leaps of both faith and logic.

<edit> I'm not giving examples as it leaves the door wide open for nit-picking and distractionary discussion </edit> All pretty huge leaps from one useful thing to another useful thing with a gert big pile of useless bits and pieces in between - most of which would be a hinderance - without the necessary support systems and so on in place to actually make use of them.

Huge leaps all over the place.
All of them supported by vague/general arguments, sidesteps or faith.

The one thing that's for certain is that it's here and it's utterly amazing.


<edit> I'm starting to think I shouldn't have posted at all, I certainly don't want a debate. At least I'll make a Hurculean effort and get back OT... Robin - the segment you linked was fascinating and a great explanation of just how immensely complex ecosystems are. Thanks for posting it! </edit>

 

[gregorach]

I can think of a couple of ways... You could start with a larva close to pupation (and so not needing much more food) getting picked up and nurtured by the ants for whatever reason (who quite possibly weren't as selective as they are now, as the was nothing previously trying to parasitse them in this way). Once that happens, it's obviously got a major survival advantage, so the trait would sweep through the rest of the population fairly quickly. After that, it's just a question of further refinement to the mimicry, probably involving some co-evolution with the ants, and starting to eat ant larvae by get picked up earlier in its life cycle.

Or you could start off with butterfly larvae moving onto diverse insect food sources, then developing adaptations to allow it to fool the ants, and then becoming specialised to eat only ants.

I suspect the real story is probably neither of those, but whatever it was, it only takes a very marginal advantage at each step to get strongly selected in a fast reproducing r-selected species.