Two flatworms of the species Pseudobiceros bedfordi preparing for penis fencing. P. bedfordi is exceptional in that it applies sperm onto the partner's skin rather than injecting it.
Penis fencing is a mating behavior engaged in by many species of flatworm, such as Pseudobiceros hancockanus. Species which engage in the practice are hermaphroditic; each individual has both egg-producing ovaries and sperm-producing testes.[1]
The flatworms "fence" using extendable two-headed dagger-like stylets. These stylets are pointed (and in some species hooked) in order to pierce their mate's epidermis and inject sperm into the haemocoel in an act known as intradermal hypodermic insemination, or traumatic insemination. Pairs can either compete, with only one individual transferring sperm to the other, or the pair can transfer sperm bilaterally. Both forms of sperm transfer can occur in the same species, depending on various factors.[2]
^Leslie Newman. "Fighting to mate: flatworm penis fencing". PBS.
^Schmitt, Valerie; Anthes, Nils; Michiels, Nico K (2007-07-04). "Mating behaviour in the sea slug Elysia timida (Opisthobranchia, Sacoglossa): hypodermic injection, sperm transfer and balanced reciprocity". Frontiers in Zoology. 4: 17. doi:10.1186/1742-9994-4-17. ISSN 1742-9994. PMC 1934903. PMID 17610714.
Penisfencing is a mating behavior engaged in by many species of flatworm, such as Pseudobiceros hancockanus. Species which engage in the practice are...
also practice so-called penis-fencing, in which two males hang face to face from a branch while rubbing their erect penises together. ...Perhaps the...
internally by copulation. Some of the larger aquatic species mate by penisfencing, a duel in which each tries to impregnate the other, and the loser adopts...
two such worms involves penisfencing, as each worm tries to inject sperm into the other with one of its two stubby penises, while trying to avoid being...
the family Pseudocerotidae. This species has two penises, which it uses to engage in penisfencing, attempting to inject sperm into its opponent in order...
hermaphrodites. This particular genus engages in penisfencing. When the "winner" touches its penis to the "skin" of the other, insemination occurs, and...
hyenas, male and female, were born with what appeared to be a penis. The apparent penis in female spotted hyenas is in fact an enlarged clitoris, which...
internally by copulation. Some of the larger aquatic species mate by penisfencing – a duel in which each tries to impregnate the other, and the loser...
hang from a tree limb face-to-face while penisfencing. This also may occur when two males rub their penises together while in face-to-face position....
much more internal and invasive method displayed by flat-worms called Penisfencing where hermaphroditic organisms will flight to try and impregnate their...
Hermaphroditic flatworms reproduce by "penisfencing". Individuals "fence" with penises, attempting to use their penis to pierce the skin of the other and...
showed small genetic difference in the species Pseudoceros bifurcus. Penisfencing is not purely for reproduction and is not an aggressive battle of insemination...
S2CID 55535847. Chim, C. K.; Ong, Rene S. L.; Gan, B. Q. (2015). "Penisfencing, spawning, parental care and embryonic development in the cotylean flatworm...
tissue. These organisms participate in penisfencing, which is a behavior where the flatworms use their extended penises to stab and inseminate the other,...
impregnating them, forcing them to act as the female, an act commonly called "penisfencing." From here, the female lays eggs into a substrate, which hatch planktonic...
or athletic supporter, is an undergarment for protecting the scrotum and penis or vulva during contact sports or other vigorous physical activity. This...
theory of mind November 17, 2017 270 Dr. Danna Staaf Humboldt squid, penisfencing among hermaphroditic flatworms, calamari pre-date the dinosaurs, and...
prominent tower the capitol is popularly nicknamed "Tower on the Plains" or "Penis of the Plains." The capitol and its grounds are a frequent site of political...
slammed into face (6/10) Electric whisk on tongue (6/10) Electric whisk on penis (7/10) (Not broadcast) Onions squeezed into eyes (10/10) Alex Zane's Games:...
anything from rolled up socks to specially made packers, which resemble a penis. Some packers are also created for trans men to be able to urinate through...
during fights. Males sport a roughly egg-sized sack near the opening of the penis, which collects urine and emits a sharp odour. The function of this sack...
who brutally tortures and eventually castrates him. Ramsay sends Theon's penis in a box to Balon, with Ramsay threatening to mutilate Theon more unless...
December 2014, specialists at the university performed the first successful penis transplantation on a 21-year-old man. Stellenbosch University was the first...
Global Information