So a queen propagates her colony by mating with her sons, until a new queen goes off to form a new colony by screwing her brother.
Wouldn’t this produce an unvaried genetic code meaning that a single disease should have wiped out ants ages ago? Each species might have their own anti-bodies, but eventually, every species should be wiped out by now. Am I wrong on the lack of genetic variance?
Not sure about ants. For bees, the hive welcomes all drones, who sit around eating honey and doing nothing, waiting for their chance to mate (hence the negative connotation of the name drone). This means the drones could be from down the road or across the forest, thereby creating diversity.
IIRC, the one who succeeds in mating dies in flagrante; the others are given the boot when the hive begins battening down the hatches for winter.
New queens also mate with males from other nests, so while each colony is “inbred”, there is plenty of sexual reproduction and genetic variation between colonies.
Bees only welcome drones from their own hive. Otherwise you are spot on. Drones sit around and eat and, whenever they feel like it, go out looking for someone to screw. If somebody were to create a video game system for bees, drones would bare a frightening resemblance to some young men I know.
Queens fly out to mate a few times when they are young and then settle down to make eggs for the rest of their lives. They don’t mate anymore once they are fertilized. I assume ants are the same.
That’s not now it works (well, not in the cases I’ve seen) - colonies produce winged males and females, they all swarm out and mate with individuals from other colonies - the males then die, the females tear off their own wings and some of them succeed in becoming new founder queens.
The swarms are synchronised across multiple colonies by weather cues and the like, ensuring that when the virgin queens take wing, there will probably be non-sibling males available to mate with them.
ETA: NB: I’m only describing some examples - I’m sure there are other strategies too, as there are a great many different ant species and they have quite diverse behaviours.
Except I heard on Radio Lab that there’s two families of Argentine Ants that don’t do that. They viciously attack any ants that aren’t from their colony, and as a result, ended up spreading quite successfully across large parts of the planet. There’s apparently a boundary line in California where the two families meet and kill each other by the millions. Link here, it’s fascinating stuff.
Presumably, these ants could experience a genetic wang-dang-doodle such as the one you describe, but they’re so prolific and spread out now that they may be able to evolve separately over time. Of course, that brings up the question of what gene expresses the “Argentine family” scent, and how much the separated groups of Argentine ants can evolve before they start turning on each other. The ants’ conquest of the globe only happened within the last century, so I figure they’ve got some time.
ETA: I guess they’re not going to evolve much if they don’t interbreed with other ants, so I guess they’d be dependent upon beneficial mutations?
Queen ants only mate once (except those who reproduce parthenogenetically, who don’t mate at all), and don’t start laying until afterwards, so it’s impossible for a queen ant to mate with her own son.
It’s possible, though not particularly likely, that one will mate with her brother- unlikely, as they form massive swarms of reproductives from many colonies. It’s no more likely than in other insects which mate in swarms.
Termites, incidently, mate repeatedly with the same partner through their lives, so have both a ‘queen’ and a ‘king’, which are again normally reproductives coming from seperate colonies.
Eta: Just discovered that ants (or bees, or wasps) very rarely suffer from any inbreeding problems, due to the pheomenon known as haplodiploidy- which means that males only have one copy of each allele, rather than two. This means that any problem alleles will be weeded out, as they can’t ‘hide’ by being recessive, as they will automatically be expressed by the male.
Researchers have observed pretty major population crashes of Argentine ants in New Zealand. They haven’t identified a mechanism, but it could be relevant to the OP. Being particularly genetically homogeneous, it stands to reason that it’s only a matter of time before a pathogen cracks their histocompatibility codes and wreaks havoc.
http://www.scoop.co.nz/stories/SC1111/S00064/populations-of-invasive-ants-die-out-naturally.htm
I just read in this book that insect immune systems are fixed at birth; as they age, they do not develop immunity to new pathogens to which they are exposed. Apparently they rely on huge population numbers (and the mutations that occur with new generations) to keep up in their struggles against infectious agents.
That might indeed indicate a monoculture of genetically-similar ants could eventually run into trouble.
In the case of the NZ ants, the issue is founder effect more than anything, I think.
Wikipedia, Drones
If I recall from my interest in bees back in the 1960’s, as mentioned by Wikipedia, drones drift from hive to hive; they are fed by the worker bees there regardless of origin.
Okay, thanks for all the info, guys. I guess I confused something I read. Ignorance fought.
Heh. For the record, I meant to link to a book, hence my use of “this book:”
The Genius Within: Discovering the Intelligence of Every Living Thing