It's a boy! Oh wait,
its a girl! No, its BOTH!
Hirudo medicinalis
is hermaphroditic, meaning it has both
male and female sex organs that produce male and female gametes. There
is a common misconception that hermaphroditic animals can fertilize
their own eggs, but in most cases, species do not self-fertilize. For
most, it is physically impossible due to the positioning of their sex
organs. So what are some benefits of hermaphrodism? Let's say that you
were an organism that occupied an area with few organisms of your own
species. If you were a male, you would have to worry about finding a
female to reproduce, and visa versa. Hermaphrodism takes the worry out
of that possible issue. If you found another member of your species,
you could cross fertilize and the BOTH of you can reproduce, making it
more likely to perpetuate the species.
Two leeches
presumably mating. Photo
courtesy of Lars L. Iverson
Talk
about different
Reproduction
in leeches is, well, weird to say the least and the exact details of
this process is still a little sketchy. During
mating season, which typically runs through early June to August,
leeches of reproductive maturity start producing sperm and eggs. The
clitellum (band of tissues that secretes the cocoon) may become
enlarged and visible during this time of year. When
two leeches find one another and decide to mate, they line up with
each other, and one will attach a sac filled with sperm
(called a spermatophore) to the other. The sperm are then released from
the sac and literally pierce through the skin of the leech, eventually
finding its way to the ovaries. When the sperm finally find their way
to the egg and fertilize it, the leech begins to make a cocoon by
secreting thick fluids from the clitellum. The eggs are then inserted
in the cocoon and the leech finds a good place to put it. Many
biologists are surprised by what most types of leeches do after the
cocoon is made. Since it can take several days for the
cocoon to harden, some leeches actually cover it with their bodies to
protect it from predators and the environment. Other species of leech
will actually wait until the eggs hatch and then transport their babies
to their first meal. Most people are surprised to hear that these blood
sucking parasites are in fact good mothers!
Click
HERE
to learn about how
Hirudo
medicinalis is used in medicine
Click
on the link below to visit the University of La Crosse website |
Click on the link below to see other
organism websites made by UW-L students at multipleorganisms.net |
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