Male penile propulsion

[BlodwynPig]

This paper just "popped" into my inbox

Male penile propulsion into spiraled spermathecal ducts of female chrysomelid beetles: A numerical simulation approach

Alexander Filippova, Alexander Kovaleva, Yoko Matsumuraa, Stanislav N. Gorba

Abstract
Genital diversification in animals is an interesting evolutionary phenomenon. Sexual selection is the main driving force behind the diversification. However, evolutionary mechanisms that have established and maintained variations in genitalia shape parameters observed in related species are not well understood. Here, for the first time, we used numerical simulations to test the hypothesis that variations in female spermathecal duct shapes among related beetle species mechanically interfere with penile propulsion in varying ways. Our numerical simulations showed that high curvature of the spiraled spermathecal ducts of the female have effects with a threshold-based interaction on male penile insertion. The relative size of spirals observed in the beetle, Cassida rubiginosa, studied here is not small enough to interfere with penile propulsion. But the model revealed that propulsion is impeded by the presence of reverse turns in spermathecal ducts. This type of morphology leads to an increase in the velocity of the propulsion but also to an increase in the propulsion energy cost for males. Our results showed that quantitative differences in spermathecal duct shape can mediate qualitative differences in penile motion. This explains, in part, the mechanism behind origin and maintenance of genital divergence among closely related species in general.



A graph

[Paul Calf]

That's some quality spam. I only get viagra and 419 scam letters. I feel somewhat inadequate.

[mook]

mate... diagrams c & d are the cords from a trim phone. don't try & sex it up with talk of russians & A GRAPH.


this thread STINKS... 3/10... still better than anythinf birdie/dangerman can knock out though.

[BlodwynPig]

Aren't Spaniel's appendages also spirals?

[mook]

you're thinking of pig's outwardsnesses. again.

spaniels are only available in one form. & that is "gel". you tit.

[Birdie]

this thread STINKS... 3/10... still better than anythinf birdie/dangerman can knock out though.

Mean. But our names do look good together don't they?

Someone should tell Filipova et al that they have wasted their lives.