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Go to: The Descent of Edward Wilson (with Polish translation)

candide94's Avatar Jump to comment 7 by candide94

@ brighterstill

Well, the door lockers wouldn't follow a specific genetic path because door lockers are never going to have children. The door lockers will have sisters who are going to grow up to be queens, who will often carry the door locking genes and spread them to the colonies they set up. In ants, caste is determined by either how an ant was raised or by its age. (e.g in some species, the youngest ants are the nursemaids, the next oldest are the nearby foragers, the oldest are the scouts). So (generalizing hugely) in most species every female ant has the potential to be of any caste, and depending on the temperature the egg from which she hatched was incubated will either be queen or worker) and the depending on her age will be of that caste or this. In a sense, there is a doorlocking caste in that on the evening the elderly ants happen to be last in the door, a behavioural switch is triiggered and the stereotypic responses locked in their genes are brought to life by the situation...

Admittedly, in species where caste is determined by morphological differences (usually size), you make a soldier of an ant by feeding more, a cleaner by feeding it less. So you could imagine that in a hypothetical ant colony evolution might have favoured for the nursemaids to feed the least food to the ants who were going to grow up to become the doorlockers. And by virtue of feeding them so little, a behaviour was triggered and the ants naturally did the door locking when left their by the nursemaids. Imagine that, kids being raised to go and die for the greater good...

Anyway, too much speculation is addictive!!!

Thu, 24 May 2012 17:19:10 UTC | #943316

Go to: The Descent of Edward Wilson (with Polish translation)

candide94's Avatar Jump to comment 3 by candide94

@Serdan @Antipodesman

Here is a lovely (as in fascinating) example of ants sacrificing themselves to help their kin.

http://www.newscientist.com/article/dn14821-heroic-ants-pay-the-ultimate-price-to-safeguard-nest.html

Every evening at sunset the ants seal the door to their nest. But a few ants always stay outside to kick sand over the entrance to disguise it better. A large proportion of the ants left outside die of the cold, are blown away or eaten by predators. Hence, every night a number of ants must sacrifice themselves to ensure the protection of the rest of the colony.

This is very interesting as there is no caste that does this, it seems to be a behaviour wired into all the ants which is activated by certain circumstances, i.e. being of the right age to be last in the door. (so they don't get in the door at all!)

Now if we consider Hamilton's rule, this all makes perfect sense. Think of all those genes for "sacrificing yourself to lock the door" swarming inside the colony (or rather inside the queen in the colony, and in the potential queens in the colony). The cost to the individual may be huge (i.e. death) but rB >>>>>>> C because of, first, the fact there are individuals carrying that gene in the nest who will go onto reproduce a helluva lot and second, the fact this behaviour is very important in letting the queen go onto reproduce as it prevents predators sneaking in and attacking the nest (and her) at night.

Obviously RD's book explain this far better than me, but I thought this was a good example.

Thu, 24 May 2012 16:31:04 UTC | #943305

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