RE: About those Piranha Bugs - LOOOOONG (and more LOOOOONG)

I would tend to model the pirahna bugs on a bee type system.  Some
comparisons first:

Pirahna bugs are relatively small and numerous, so are bees.

Assuming the pirahna bugs are living in nest because they are colony
type bugs, it would be implied that they are gathering food for the
hive, not the individual.  This in turn implies some sort of transport
capability as well as storage ability.	This again would make them
simlar to bees.

You can pack several hives of bees relatively close together (e.g.
beekeeping).  Bees roam miles and miles to gather their food even if
hives are in close proximity.  So it would be possible for several hives
to cover the same territory.

I suspect that bees are less competitive simply because it is difficult
to steal their nectar/pollen easily in transit.  Highly combative or
predatory insects tend to be over the types of food that are easily
stolen - whole leaves, grubs, insect parts.

If pirahna bugs operate on the idea that they are transporting food back
to the hive, I would think it unlikely that they are merely grabbing a
bite and taking back a mouthful.  At the other extreme, I think it
unlikely that they are ripping out large chunks (relative to body size)
and hauling those back either.	A more likely scenario is that they take
a few bites, store them in some type of internal sac and regurgitate
back at the hive.  It may even have the advantage of being pre-digested
for grubs or queens.  There is probably some type of liquid storage in
the hive.  

If the mechanism is somthing like this, it would seem more advantageous
to have greater numbers of workers to rapidly dissect and transport a
food source rather than wasting effort on breeding soldiers to intercept
or guard against opposing workers since you don't directly benefit by
killing opposing workers (i.e. you can't steal their package of food). 
It would be a more successful strategy of having overwhelming numbers of
workers so that if a food source does appear, you can grab more of it in
a shorter amount of time.

I would also think that this type of insect is more of a scavenger
rather than an active hunter, looking for non-moving flesh, rather than
actively hunting down moving creatures.  If this is the case, the local
fauna may not see them as a major threat and be willing to live among
such hives.  If there is a high concentration of fauna, there are
probably more carcasses for the hives to feed off of.  

Alternatively there may be a symbiotic relationship with some type of
animal or plant.  It may be that a fungus grows on their droppings, and
this fungus attracts various birds, small animals or even larger animals
in times of drought or famine.	Everyone wins - animals have a backup
food supply in times of famine, and if one or two gets eaten, everyone
else survives when they might have starved to death.  The fungus gets a
normally safe home and lots of material to grow on.  The pirahna bugs
get waste handling and a lure for food.

Alternatively the bugs can life off the fungus and merely supplement
their diet with the occasional high protein snack.  There are many
variations of this PSB to explain how they work.  I'm always amazed at
the stuff we find on earth - i.e. bacteria that lives in near boiling
water, creatures that can survive tremendous pressures in the depths of
ocean trenches, the fact that ravens can count up to 7 and make tools,
modified bacteria that lives inside our cells (mitochondria), beds of
fungus that stretch for acres and are estimated to have lived for
thousands of years, etc.

I've always been interested in the "Deathworld" type ecosystems and
trying to figure out how to generate one that seems plausible.	Some
examples are David Drake's "Surface Action" and "Redliners" and the
"Deathworld Trilogy" by Harry Harrison.

--Binhan

> -----Original Message-----
> From: Brian Bilderback [mailto:bbilderback@hotmail.com]
> Sent: Friday, January 11, 2002 1:14 PM
> To: gzg-l@csua.berkeley.edu
> Subject: About those Piranha Bugs - LOOOOONG
> 
> 
> I was lying awake last night thinking about the posts on the 
> Piranha bugs 
> scenario (I know, I know.... I'm shopping for a life this 
> weekend).  While I 
> have no problem with the idea of the bugs themselves, 
> something about it 
> didn't quite stick right, and I finally put together my 
> thoughts/suggestions 
> on the subject.
> 
> Let me preface them by making a couple of disclaimers.
> 
> First I am NOT a biologist.  If anything I say is incorrect, 
> I'm sure Beth 
> will set me straight in her usual gracious manner.  Heck, I'm 
> not an expert 
> at ANYTHING  -- but I am familiar with many subjects.  
> Unfortunately, the 
> downside of being so easily interested is I am also easily 
> distracted.  
> Anyone who knows me well but choses not to like me might even 
> accuse me of 
> being a bit of a dilletante.	But I think I've picked up 
> enough to make this 
> make sense.
> 
> Second, I will be making some comments based on general 
> observations.  I in 
> NO way claim that ANY of these are hard fast rules.  I will 
> do my best to 
> use phrases like it SEEMS, TENDS, GENERALLY, etc.  I know 
> that any time you 
> post an opinion about a general trend, many on the list like 
> to reply with 
> some example of something that bucks the trend.  I'm well 
> aware that there 
> are exceptions to these general tendencies, but I do NOT 
> think that detracts 
> from the validity of the observations.
> 
> Having said all that, away we go:
> 
> I noticed that it was stated that there were numerous mounds 
> of these bugs 
> within proximity to one another,  While the bugs themselves are quite 
> believable, I have a problem with this.  This is why.  
> Colonizing insects 
> TEND to protect their nests/lairs VERY violently - as the 
> scenario attests.  
> Predatory animals, particularly social ones, TEND to be very 
> territorial.	
> Combine the two, as in Colonizing Predatory Insects, and you 
> TEND to get 
> animals that are EXTREMELY turf-conscious.  I've seen footage 
> of ants going 
> at it with other ants over nests/territory - it ain't pretty. 
>  Makes many 
> human wars seem calm when taken in scale.
> 
> So these bugs aren't going to want bugs from another nest in their 
> territory.  Fair enough.  But why can't the territory be 
> small enough that 
> these mounds can be within a couple hundred metres?  Well, 
> remember they're 
> predatory.  Predator territories AS A GENERAL RULE have a 
> relationship to 
> the amount of food required by the predator and the amount of food 
> available.  The more a predator eats, and the more often it 
> has to eat, the 
> larger the territory it tends to try to defend.  And the 
> frequency (even 
> more than the amount at any one meal) that a predator must 
> eat tends to be 
> related to it's metabolism.  And small, quick, active, flying 
> animals (eg 
> hummingbirds) tend to need to eat more frequently.  Which 
> means these bugs 
> probably need to eat pretty frequently.  This means that 
> either the country 
> around them is carpeted in prey animals, or they must 
> maintain a fairly 
> large territory.  That's why I doubt there'll be many mounds 
> close together. 
>   I could be wrong.  But if I ran them in a scenario, I'd have a nest 
> density of maybe 1-2/Km2....
> 
> Brian B2
> 
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