[NatureNS] Earwig bashing backlashing

Date: Tue, 17 Nov 2009 13:57:31 -0400
From: Stephen Shaw <srshaw@dal.ca>
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Hi Angus & other dermaptophobes:  Even in your likely role here as agent
provocateur, Angus, your nonchalance about the fate of the St Helena Giant
Earwig should raise a few eyebrows. It now appears to be extinct, and is not
being rescued by taxpayer ecodollars as far as I could make out from reading
some of the same sources as you (the last 3 searches for it by visiting
entomologists failed, on this small island -- surveying insects in unique
habitats is what some entomologists do professionally).

Turning this around, would you have been equally unhappy if a small 
part of some
state's funds were to be expended in an attempt to save the Great Auk, 
the last
couple of which were clubbed to death for food by sealers as I recall, or the
Dodo, likewise?  Birds, yeah, earwigs, nay?  If this is your position, then
closer to home for the SHGE, are you equally unconcerned that the SHGE`s bird
predator, the now extinct St Helena Giant Hoopoe, may have coughed its last in
part because an important food source disappeared?  The suspected cause of
extinction of the SHGE itself is destruction of the Gumwood Forest at one
end of St. Helena.  So, perhaps clear-cutting -> SHGE extinction -> SHG Hoopoe
extinction, reinforcing the interconnection of living things in complex
ecosystems, and the need to avoid disrupting same where possible.

As to how the particular (alien, unloved) earwigs here can survive under water
for a while, insects breath through lateral spiracles coupled to tracheae,
internal air tubes that run directly into the tissues.  At least in some cases
well investigated like the cockroaches you mention, the spiracles have both
protective guard hairs and associated muscles so that they can be closed off
completely by the insect, and in addition the outer parts of the 
tracheal tubes
are hydrophobic (unwettable), like the outer cuticle.  Thirsty roaches 
are quite
happy to submerge themselves for a while to drink.  No doubt earwigs have
similar specializations permitting their dunking, but I'm sure they can't
actually live under water indefinitely.  They certainly float and will swim
around in a toilet bowl, so the question would be how yours managed to get
under water in the first place -- presumably they didn't, but simply sank when
you pulled the plug and then hung on for dear life, to anything nearby (?).
Steve


Quoting Angus MacLean <angusmcl@ns.sympatico.ca>:
> Re recent discussion on possibly dwindling populations of earwigs, I 
> would personally be pleased to see the day when they are on the 
> endangered list. However, l liken earwigs to cockroaches in that they 
> will be here long after humans are gone from this earth.
>
> In any case we had an interesting case of an earwig which was 
> adaptable to another environment. We have a backyard pond in which 
> are a number of goldish. We remove them from the pond for the winter. 
> A few days ago my wife noted something on one of them when we took 
> them out. It was an earwig !!) latched on to the goldfish.
>
> We have to partially drain the pond in order to net them so only 
> about 3-4 ins of water is left. Although it is known that earwigs 
> like wet conditions (try leaving a wet mop out overnight), there is 
> no indication they can live in water. There must be an explanation 
> but...??
>
> Incidentally there is one earwig, the St. Helena Earwig, on the 
> endangered list. It is the largest earwig in the world and recovery 
> plans are already underway. How scarce resources and monies are 
> wasted! (I expect a backlash re the latter statement).
>
> Angus



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