I*i
2 楼
英文名Damselfly
请看下面这篇有关蜻蜓、豆娘的科普文章
http://insects.about.com/od/dragonfliesanddamselflies/p/How-Dra
How Dragonflies Mate
By Debbie Hadley
Dragonfly sex is a rough and tumble affair. If you've ever seen a pair of
mating dragonflies in the throes of passion, you know that their sexual
coupling requires the flexibility and acrobatic skill of a Cirque de Soleil
performer. Females get bitten, males get scratched, and sperm winds up
everywhere. These strange mating habits have survived millions of years of
evolution, so the dragonflies must know what they're doing, right? Let's
take a closer look at how dragonflies mate.
Dragonfly Courtship:
As you might imagine, dragonflies don't engage in elaborate courtship
rituals. In a few families, the male dragonfly may display his colors, or
fly over his territory to show a potential mate what a good oviposition site
he's chosen for their offspring, but that's about it. Dragonfly foreplay
leaves much to be desired.
Because dragonflies have extraordinarily good vision, the males rely mostly
on their eyesight to find appropriate female partners. Since a typical pond
or lake habitat will support many species of dragonflies and damselflies, he
must be able to distinguish females of his own species from all the other
Odonates flying around. A male can recognize a conspecific female by
observing her flight style, her colors and patterns, and her size.
Dragonfly Mating:
As with many insects, male dragonflies make the first move to initiate sex.
When a male spots a female of his own species, he must first subdue her. He'
ll approach her from behind, usually while they are both in flight, and hold
onto her thorax with his legs. If he's feeling feisty, he might bite her,
too. If he hopes to mate successfully, he must get a firmer grip on her
quickly. The male dragonfly will pull his abdomen forward and use his anal
appendages, a pair of cerci, to clasp her by the neck (her prothorax). Once
he has her tightly by the neck, he can extend his body and continue to fly
with her, in tandem. This position is known as tandem linkage.
Now that he's got a hold of a mate, the male dragonfly needs to prepare for
sex. Dragonflies have secondary sex organs, meaning they don't store sperm
near the copulatory organ. He must transfer some sperm from a gonopore on
his ninth abdominal segment to his penis, which is located under his second
abdominal segment. Once he's charged his seminal vesicle with sperm, he's
ready to go.
Now for the acrobatics. The female's genital opening is near the tip of her
abdomen, while the male's penis is closer to his thorax (on the underside of
his second abdominal segment). The female must bend her abdomen forward,
sometimes with coaxing from the male, to bring her genitalia into contact
with his penis. This position during copulation, known as a wheel formation
because the couple forms a closed circle with their joined bodies, is unique
to the order Odonata. In dragonflies, the sex organs lock together briefly
(not so for damselflies). Some dragonflies will mate in flight, while others
will retire to a nearby perch to consummate their relationship.
Competition Among Male Dragonflies:
Female dragonflies operate by the "last in, first out" rule of fertilization
. If given the opportunity, she might mate with multiple partners, but the
sperm from her final sexual partner will fertilize her eggs, in most cases.
Male dragonflies, therefore, have an incentive to make sure their sperm is
the last to be deposited in her.
A male dragonfly can increase his chances of fatherhood by destroying the
sperm of his competitors, and he's well equipped to do so when he mates.
Some dragonflies have backwards-facing hooks or barbs on their penises,
which they can use to scoop out any sperm they find inside their partner
before depositing their own. Other dragonflies use their penises to tamp
down or move the offending sperm, pushing it aside before he places his own
in the ideal location for fertilization. Still other dragonfly males will
dilute any existing sperm they find. In all cases, his goal is to ensure
that his sperm supersedes that of any prior partners she has had.
Just to provide an added measure of security for his sperm, the male
dragonfly will often guard the female until she oviposits her eggs. He tries
to prevent her from mating with any other males, so his sperm is assured
the "last in" position that will make him a father. Male damselflies will
often continue to grasp their partners with their cerci, refusing to let go
until she oviposits. He'll even endure a dunking in the pond if she
submerges to place her eggs. Many dragonflies prefer to guard their partners
by simply chasing off any approaching males, even engaging in wing-to-wing
combat if necessary.
请看下面这篇有关蜻蜓、豆娘的科普文章
http://insects.about.com/od/dragonfliesanddamselflies/p/How-Dra
How Dragonflies Mate
By Debbie Hadley
Dragonfly sex is a rough and tumble affair. If you've ever seen a pair of
mating dragonflies in the throes of passion, you know that their sexual
coupling requires the flexibility and acrobatic skill of a Cirque de Soleil
performer. Females get bitten, males get scratched, and sperm winds up
everywhere. These strange mating habits have survived millions of years of
evolution, so the dragonflies must know what they're doing, right? Let's
take a closer look at how dragonflies mate.
Dragonfly Courtship:
As you might imagine, dragonflies don't engage in elaborate courtship
rituals. In a few families, the male dragonfly may display his colors, or
fly over his territory to show a potential mate what a good oviposition site
he's chosen for their offspring, but that's about it. Dragonfly foreplay
leaves much to be desired.
Because dragonflies have extraordinarily good vision, the males rely mostly
on their eyesight to find appropriate female partners. Since a typical pond
or lake habitat will support many species of dragonflies and damselflies, he
must be able to distinguish females of his own species from all the other
Odonates flying around. A male can recognize a conspecific female by
observing her flight style, her colors and patterns, and her size.
Dragonfly Mating:
As with many insects, male dragonflies make the first move to initiate sex.
When a male spots a female of his own species, he must first subdue her. He'
ll approach her from behind, usually while they are both in flight, and hold
onto her thorax with his legs. If he's feeling feisty, he might bite her,
too. If he hopes to mate successfully, he must get a firmer grip on her
quickly. The male dragonfly will pull his abdomen forward and use his anal
appendages, a pair of cerci, to clasp her by the neck (her prothorax). Once
he has her tightly by the neck, he can extend his body and continue to fly
with her, in tandem. This position is known as tandem linkage.
Now that he's got a hold of a mate, the male dragonfly needs to prepare for
sex. Dragonflies have secondary sex organs, meaning they don't store sperm
near the copulatory organ. He must transfer some sperm from a gonopore on
his ninth abdominal segment to his penis, which is located under his second
abdominal segment. Once he's charged his seminal vesicle with sperm, he's
ready to go.
Now for the acrobatics. The female's genital opening is near the tip of her
abdomen, while the male's penis is closer to his thorax (on the underside of
his second abdominal segment). The female must bend her abdomen forward,
sometimes with coaxing from the male, to bring her genitalia into contact
with his penis. This position during copulation, known as a wheel formation
because the couple forms a closed circle with their joined bodies, is unique
to the order Odonata. In dragonflies, the sex organs lock together briefly
(not so for damselflies). Some dragonflies will mate in flight, while others
will retire to a nearby perch to consummate their relationship.
Competition Among Male Dragonflies:
Female dragonflies operate by the "last in, first out" rule of fertilization
. If given the opportunity, she might mate with multiple partners, but the
sperm from her final sexual partner will fertilize her eggs, in most cases.
Male dragonflies, therefore, have an incentive to make sure their sperm is
the last to be deposited in her.
A male dragonfly can increase his chances of fatherhood by destroying the
sperm of his competitors, and he's well equipped to do so when he mates.
Some dragonflies have backwards-facing hooks or barbs on their penises,
which they can use to scoop out any sperm they find inside their partner
before depositing their own. Other dragonflies use their penises to tamp
down or move the offending sperm, pushing it aside before he places his own
in the ideal location for fertilization. Still other dragonfly males will
dilute any existing sperm they find. In all cases, his goal is to ensure
that his sperm supersedes that of any prior partners she has had.
Just to provide an added measure of security for his sperm, the male
dragonfly will often guard the female until she oviposits her eggs. He tries
to prevent her from mating with any other males, so his sperm is assured
the "last in" position that will make him a father. Male damselflies will
often continue to grasp their partners with their cerci, refusing to let go
until she oviposits. He'll even endure a dunking in the pond if she
submerges to place her eggs. Many dragonflies prefer to guard their partners
by simply chasing off any approaching males, even engaging in wing-to-wing
combat if necessary.
h*h
3 楼
高难度特技动作。
h*t
4 楼
我看了半天没看懂它们在搞什么,一个把尾巴贴到另一个的背上?
I*i
7 楼
科普文章在二楼:How Dragonflies Mate
e*o
8 楼
为啥叫豆娘豆叔?
d*y
9 楼
打喷嚏了,上来看看~~~~
F*s
12 楼
华丽丽的紫边啊~~~~~~~~~~~~
烧器材吧~~~~~~~~~~
嘻嘻~
烧器材吧~~~~~~~~~~
嘻嘻~
I*i
17 楼
l*t
25 楼
发散下...这个样子很像战斗机空中加油...
T*m
37 楼
都是高难动作啊!身体不好的人,请不要试。
a*a
39 楼
精彩瞬间,就是费眼,哈哈
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