On Mon, Jan 26, 2004 at 04:43:33PM -0800, Julie Alipaz wrote: > First RSSD is not limited to birds: marine mammals--some Hyenas too, I thought. Bigger and more aggressive (more testosterone) than the males. (Why aren't they male themselves? Because they have even more estrogen.) > Other examples of RSSD: lizards, turtles (the norm here, 31 out of 32 > species) mustelids, insects and baleen whales show RSSD; jacanas > (another bird) And spiders. > parasitic on females; they attach themselves to a female, going so > far as to tap into her digestive tract, so the female actually feeds > them. The only thing the female needs from the male is sperm--they > are called parasite males--and possibly evolved due to the above > competition issue. I think sperm in general are parasite gametes in the sexual process; some thought is that the original sexual gametes would have been 'fair', or equal in size, but it makes sense for one half to cheat and make lots of smaller gametes and off the race goes. The same logic should probably apply to actual males, except when offset by competition-for-mating issues, which turns out to be pretty often. -xx- Damien X-)