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A male and female schistosome worm in all their mated-pair glory. The male is the larger individual; the female can be seen peeking out of his gynacophoric canal -- a ridge along his belly that serves as her home.
SEM photograph by Bruce Wetzel and Harry Schaefer, National Cancer Institute.
Posted by DianeAKelly on February 19, 2010 | Permalink
That's interesting. I originally guessed the opposite before I read the comment. Isn't large female, small male more common? Or have I been misled simply because the cases of female/male size disparity are popularized?
Thom H. |
March 01, 2010 at 12:29 PM
It depends on the particular species and the details of their life history. There are species with larger males that fight for territory and access to smaller females (like elk or lions), species with large females and tiny males (like many spiders or deep-sea anglerfish), species where the two sexes are about the same size (like garden snails or Canada geese), and species where size change eventually leads to a sex change. As it turns out, the size difference in schistosomes changes with the variable you measure: females are a bit longer than males, but males are a bit thicker than females.
March 02, 2010 at 10:57 PM
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