[continued from previous message]   
      
   So here we see the benefits to us of reading the actual paper, in which   
   it turns out that all the workers are hybrids. The M. structor male does   
   indeed contribute to their genomes, which is presumably an advantage in   
   maintaining genetic diversity.   
      
   >>> My guess that initially the hybridization between the two species   
   >>> selected for queens prone to non disjunction in Meiosis I.  These   
   >>> defective queens would have been the ones to benefit from mating with   
   >>> another species whose DNA they didn't need.   
   >>   
   >> What benefit?   
   >   
   > Below.  A female prone to nondisjunction is at a disadvantage because   
   > she is producing empty eggs (0N) and 2N egg cells, so she will produce   
   > too many 1N male offspring, and not enough 2N workers and most of the   
   > workers that she does produce may have issues as triploids (they may be   
   > inviable).  Mating with a different species allowed the female to switch   
   > her egg fertilization strategy.  Normally she would produce just enough   
   > unfertilized eggs to produce males, but now she doesn't want the male to   
   > fertilize the eggs.  Her strategy had to switch to preventing male   
   > fertilization.  Initially the hybrid 2N hybrid progeny (they would have   
   > been produced until a high frequency of non disjunction was attained)   
   > were likely infertile queens, so the non disjuction females would have   
   > been selected for reproduction.  This probably allowed selection for   
   > increased frequency of non disjuction and an increse in producing   
   > unfertilized eggs.   
      
   All moot, given that the workers are all hybrids.   
      
   >>> For normal matings the triploids produced would have difficulty   
   >>> reproducing or there might have been a lot of dead triploid embryos   
   >>> produced, so the queens prone to non disjunction would have been   
   >>> selected against.   
   >>   
   >> The question isn't why the queens mate with non-conspecifics. The   
   >> question is why they mate at all.   
   > The females likely need to mate before completing their development into   
   > egg laying machines, and there is also the selective factors of evolving   
   > an animal prone to a high frequency of non disjunction.  Mating with   
   > another species where the hybrid had reproductive issues would select   
   > for the unfertilized non disjunction queens.  This would allow for   
   > selection for non disjunction and shifting to producing more   
   > unfertilized eggs.   
      
   Again, moot.   
      
   --- SoupGate-Win32 v1.05   
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