29 January 2010

How to spot a hermaphrodite

If you had no prior information about the reproductive biology of a group of animals, say, pulmonate land snails, how would you go about determining if a given species were hermaphroditic or not?

I can think of 2 ways of doing it. First, one may dissect and compare the genitalia of many individuals. If every individual is found to have the same set of reproductive organs, one may assume that they all are hermaphrodites and then try to identify the male and female parts.

Second, one may watch or separate many mating pairs and, if one is lucky and happens to see that each individual is using its penis simultaneously to inseminate its partner, one will then conclude that they all are hermaphrodites.

But what has luck got to do with it? It turns out that, even though all pulmonate snails are hermaphrodites, in some species mating may not be simultaneously reciprocal; instead, some individuals may act like "males", while others like "females". A previous posts on this subject is here.


Julia said...

I started a drawing series last year that would probably best be titled "Self-Portraits, Mating with Slugs." this post has inspired me to pick up that thread again...


Glad to be of help. Post the drawings on your blog so we can all see them.