The Weird Sex Habits of Water Striders: Part 3
In Part 2 we described mating between males and females of the water
strider (or pond skater) species. Gerris gracilicornis. The female has a
"shield" covering her genitals that she can withdraw at her choosing.
In response to this, male G. gracilicornis have evolved a ritual where
they tap the water surface. One explanation for this was that it help
s the female detect which males are the best so she can choose who to mate with.
Some comments interpreted this "song" in a romantic way. It certainly
appeals to us - the idea that a male has to serenade a female to get her
in the mood has a very human quality! Unfortunately, subsequent
research has torn this notion down; these songs are just another part of
a male's rape repertoire.
The backswimmer (seen approaching
the mating duo in the photo) is a natural predator of water striders. It
detects its prey using vibrations in the water (in fact, given a
choice, a backswimmer always headed towards mating water striders rather
than a silent male). And backswimmers attack from below - if it finds
mating water striders, it's the female getting eaten.
Several
other points hint at this conclusion. First, if females who have been
attacked by backswimmers before are mounted, they give in almost
instantly. Females who have not been previously attacked resist for
several minutes longer. The male ceases tapping when she allows him to
mate with her. As mentioned above, if a backswimmer does attack the male
will most likely escape. The most compelling evidence is that males
actually tap faster when backswimmers are around.
It's
possible that tapping behaviour was originally a way of communicating
quality, and this behaviour emerged from that. Certainly other species
of water striders use tapping to communicate, and males of the species
Aquarius najas tap their legs during sex. However, A. najas doesn't
create the ripples and their taps have no effect on females (supporting
the idea that taps are threats). It makes sense, in a warped kind of way
- the female evolves a way to protect herself, the male evolves a way
to stop her using it.
To read the paper, click here: http://bit.ly/R2kLss
A 30-second video, where you can clearly see the taps and following attack, is available here: http://www.youtube.com/
Photo credit: Chang S. Han.
http://
The Weird Sex Habits of Water Striders: Part 3
In Part 2 we described mating between males and females of the water strider (or pond skater) species. Gerris gracilicornis. The female has a "shield" covering her genitals that she can withdraw at her choosing. In response to this, male G. gracilicornis have evolved a ritual where they tap the water surface. One explanation for this was that it help
In Part 2 we described mating between males and females of the water strider (or pond skater) species. Gerris gracilicornis. The female has a "shield" covering her genitals that she can withdraw at her choosing. In response to this, male G. gracilicornis have evolved a ritual where they tap the water surface. One explanation for this was that it help
s the female detect which males are the best so she can choose who to mate with.
Some comments interpreted this "song" in a romantic way. It certainly appeals to us - the idea that a male has to serenade a female to get her in the mood has a very human quality! Unfortunately, subsequent research has torn this notion down; these songs are just another part of a male's rape repertoire.
The backswimmer (seen approaching the mating duo in the photo) is a natural predator of water striders. It detects its prey using vibrations in the water (in fact, given a choice, a backswimmer always headed towards mating water striders rather than a silent male). And backswimmers attack from below - if it finds mating water striders, it's the female getting eaten.
Several other points hint at this conclusion. First, if females who have been attacked by backswimmers before are mounted, they give in almost instantly. Females who have not been previously attacked resist for several minutes longer. The male ceases tapping when she allows him to mate with her. As mentioned above, if a backswimmer does attack the male will most likely escape. The most compelling evidence is that males actually tap faster when backswimmers are around.
It's possible that tapping behaviour was originally a way of communicating quality, and this behaviour emerged from that. Certainly other species of water striders use tapping to communicate, and males of the species Aquarius najas tap their legs during sex. However, A. najas doesn't create the ripples and their taps have no effect on females (supporting the idea that taps are threats). It makes sense, in a warped kind of way - the female evolves a way to protect herself, the male evolves a way to stop her using it.
To read the paper, click here: http://bit.ly/R2kLss
A 30-second video, where you can clearly see the taps and following attack, is available here: http://www.youtube.com/
Photo credit: Chang S. Han.
http://
Some comments interpreted this "song" in a romantic way. It certainly appeals to us - the idea that a male has to serenade a female to get her in the mood has a very human quality! Unfortunately, subsequent research has torn this notion down; these songs are just another part of a male's rape repertoire.
The backswimmer (seen approaching the mating duo in the photo) is a natural predator of water striders. It detects its prey using vibrations in the water (in fact, given a choice, a backswimmer always headed towards mating water striders rather than a silent male). And backswimmers attack from below - if it finds mating water striders, it's the female getting eaten.
Several other points hint at this conclusion. First, if females who have been attacked by backswimmers before are mounted, they give in almost instantly. Females who have not been previously attacked resist for several minutes longer. The male ceases tapping when she allows him to mate with her. As mentioned above, if a backswimmer does attack the male will most likely escape. The most compelling evidence is that males actually tap faster when backswimmers are around.
It's possible that tapping behaviour was originally a way of communicating quality, and this behaviour emerged from that. Certainly other species of water striders use tapping to communicate, and males of the species Aquarius najas tap their legs during sex. However, A. najas doesn't create the ripples and their taps have no effect on females (supporting the idea that taps are threats). It makes sense, in a warped kind of way - the female evolves a way to protect herself, the male evolves a way to stop her using it.
To read the paper, click here: http://bit.ly/R2kLss
A 30-second video, where you can clearly see the taps and following attack, is available here: http://www.youtube.com/
Photo credit: Chang S. Han.
http://
No comments:
Post a Comment