Re: ants again

From: Anders Sandberg (asa@nada.kth.se)
Date: Tue Oct 23 2001 - 04:28:16 MDT


On Tue, Oct 23, 2001 at 04:15:25PM +0930, Emlyn O'regan wrote:
> This all takes me back... much "study" (ie: harrassment) of ants when I was
> a little tucker.

Amazing little creatures. By sheer coincidence, I watched a lengthy
documentary on ants on Discovery yesterday and when I turned on the
television this morning it was ants on the channel...

> 1 - Why do hive insects care if there is more than one queen? She doesn't
> seem to exert centralised control, so what's the big deal? Does she release
> signal hormones or something like that, which require atomicity?
>
> 2 - How do hive insects evolve??? The genes involved in reproduction seem to
> come from the queen & drones, who are far removed from the survival of the
> hive.

The workers are all the daughters of the queen, so they share a lot of
genetic material - the hive is really a big family. Having multiple
queens means that workers benefit less close relatives, and that likely
leads to defection (although many ant species do have multiple queens).
So in many situations it is likely stabler if there is just one queen.

As for evolution, the survival of the queen and drones is likely tightly
coupled with the hive survival - it provides the food, protection and
services they need, and if it fails they won't get the chance to swarm.
So I would say there is a strong selection pressure on the queen and
drones too.

> I would guess that drones must evolve to be better at mating with the queen,
> but the rest of it is a bit trickier. Are whole colonies analogous to a
> single organism in terms of reproductive fitness? If so, then we have the
> case that colonies are actually asexual reproducers, in that they split to
> reproduce; two colonies do not combine their DNA to form an offspring.

Actually, it seems that sometimes young queens from one colony mates
with drones from another colony. So they can reproduce both by splitting
(no new DNA), swarming with internal DNA mixture and swarming with
external DNA mixture.

> So, if the colony's reproduction is actually the splitting of the colony,
> then the production of individual insects is more akin to the creation of
> new cells in a human body, and plays the same role in terms of reproduction
> of the colony; that is, not much of a role at all.

Yes, this is my understanding.

> The colony would have a lifespan, or generation time, anyway, on the order
> of large animals, not on the order of non-colony insect generation times.
> How do they compete with insects which evolve far more quickly? Does the
> colony organisation put them out of direct competition with other insects,
> and into the same kind of space as larger animals???

Look at all the interesting parasites and symbionts ants have - ranging
from aphids giving them sugar excretions for protection to blue wing
butterfly larvae drugging ants to obey them. It seems that they are very
much involved in co-evolution with everything else - army ants in
Amazonas are apparently a strong selection factor among forest floor
animals.

I think ants can adapt very quickly; they seem to have switched from the
insect solution of fast reproduction and genetic change to the more
large animal solution of slower reproduction (of hives) and better
adaptation (as hives).

-- 
-----------------------------------------------------------------------
Anders Sandberg                                      Towards Ascension!
asa@nada.kth.se                            http://www.nada.kth.se/~asa/
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