Sperm warfare hots up

[Bcrazy]

I wonder if this is part cause of our loss of queens is that they suddenly become stale?


Females shut down male-male sperm competition in leafcutter ants
Leafcutter ant queens can live for twenty years, fertilizing millions of eggs with sperm stored after a single day of sexual activity.
Danish researchers who have studied ants at the Smithsonian Tropical Research Institute in Panama since 1992 discovered that in both ant and bee species in which queens have multiple mates, a male's seminal fluid favors the survival of its own sperm over the other males' sperm. However, once sperm has been stored, leafcutter ant queens neutralize male-male sperm competition with glandular secretions in their sperm-storage organ.
"Two things appear to be going on here," explains Jacobus Boomsma, professor at the University of Copenhagen and Research Associate at STRI. "Right after mating there is competition between sperm from different males. Sperm is expendable. Later, sperm becomes very precious to the female who will continue to use it for many years to fertilize her own eggs, producing the millions of workers it takes to maintain her colony."
With post-doctoral researchers Susanne den Boer in Copenhagen and Boris Baer at the University of Western Australia, professor Boomsma studied sperm competition in sister species of ants and bees that mate singlyeach queen with just one maleor multiplywith several males.
Their results, published this week in the prestigious journal, Science, show that the ability of a male's seminal fluid to harm the sperm of other males only occurs in species that mate multiply, and that their own seminal fluid does not protect sperm against these antagonistic effects.
"Females belonging to many speciesfrom vertebrates to insects-- have multiple male partners. Seminal products evolve rapidly, probably in response to the intense male-male competition that continues even after courtship and mating have taken place," said William Eberhard, Smithsonian staff scientist. "This study continues

Blimey if it aint one fing then its anover the poor queens

 

[Bcrazy]

Here is more folks!!!

Male Rivalry Extends to Sperm in
Female Reproductive Tract




SCIENCE VOL 327 19 MARCH 2010 1443
CREDIT: MOLLIE MANIER AND SCOTT PITNICK
NEWS OF THE WEEK
For males of some species, mating is just the first step toward winning the battle to pass on
their genes. Females sometimes mate more than once in quick succession, filling their
reproductive tract with rival sperm that must compete for access to the unfertilized eggs.
Two groups now show details of what life must be like for those sperm, with one offering
unprecedented movies of this sperm competition. On page 1506, Susanne P. A. den
Boer of the University of Copenhagen demonstrates that such rivalries in some ants
and bees have led to the evolution of seminal fluids containing toxins that impede rival
sperm and to female fluids that counter thes etoxins. Another team, reporting online in
Science (www.sciencemag.org/c g i / c o n t e n t / a b s t r a c t /science.1187096), followed redor
green-glowing sperm as they jockeyed their way through there productive tracts of fruit flies.
Both papers drive home the point that “the competition between males continues in a
very f ierce way” inside the female, says Tommaso Pizzari,an evolutionary biologist at the
University of Oxford in the United Kingdom. The papers provide a glimpse
of where evolutionary biology research is going: The female reproducti vetract is “one of the great, unexplored frontiersf or the fields of sexual selection and speciation,”says Scott Pitnick, an evolutionary biolog istat Syracuse University in New York state.Pitnick’s Syracuse colleague John Belote entered this frontier by developing two fruitfly lines that produce different fluorescent
proteins in the sperm head, one green and the other red. After allowing female fruit flies to
mate with one strain and then the other a few days later, Pitnick’s postdoctoral fellow Mollie
Manier videotaped the streams of red and green sperm, tracking their interactions in real
time. The first sperm in the reproductive tract swim to the fly’s sperm-storage organ, but
many are displaced by the second wave of sperm, she found. However, once both males’
sperm were settled, they all seemed to have an equal chance of fertilizing an egg.
“This is one of the most exciting development sin evolutionary and reproductive
biology—and will revolutionize the field,”says Tim Birkhead, an evolutionary biologist
at the University of Sheffield, United Kingdom.“After seeing these videos, researchers
will now think of sperm competition in anew way.”

Den Boer, University of Copenhagen colleague Jacobus Boomsma, and Boris Baer,
now at the University of Perth in Australia,find sperm in some bees and ants do more
than physically displace rivals. The team compared sperm dynamics within ant and
bee queens that mate only once with ones inwhich females mate multiple times during a
single courtship flight and store sperm foryears. For the multiple mating species studied,
two leafcutter ants and the honey bee, seminal fluid from a given male enhanced
the survival time of its own sperm in a labdish but damaged unrelated sperm and even
sperm from a brother. Adding spermatheca fluid that ant queens make within their reproductive
tract countered these effects, says Boomsma. In contrast, seminal fluids from
singly mated bumble bees and ants showed none of these negative effects.
Sperm facing competition have evolved some as-yet-to-be-defined seminal fluid
components that somehow recognize and thwart rivals, says Boomsma. But once the
sperm reach their destination for long-term storage, the female apparently wants to keep
all the sperm healthy and has evolved ways to counter the seminal fluid. This study
“beautifully reveals just how nuanced reproduction can be,” says Pitnick. “There will be
much to gain from combining our respective
approaches.” –ELIZABETH PENNISI

This could become a serious problem if not checked somehow.

Regards;