10 Interesting Facts About Sperm
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On io9 Staaf described the process, starting with the spermatophore cap popping off and the ejaculatory apparatus (every spermatophore has one) popping out and everting itself -- turning itself inside out -- pulling the sperm mass with it. But the peculiarity of squid insemination doesn’t end there. In the species known as Bleeker’s squid there are two types of male squid -- sneakers and consorts, which are kind of the Goofus and Gallant of the cephalopod world. Consorts, reports io9’s Joseph Bennington Castro, are larger, more attention-getting of the two, attracting females by “flashing bright colors across their bodies,” depositing the spermatophores in the female oviduct and then guarding her until the eggs are deposited.
Sneakers are not so, well…gallant. They sneak in between a mating pair and chuck a spermatophore in the female's external sperm storage unit so that when the eggs come forward “through her oviduct to a spot near her mouth,” the eggs that don’t get fertilized by the spermatophores of the consort -- who has put in all this courtship time -- will be fertilized by the spermatophores of the sneaker who didn’t do jack. Castro reports that Japanese researchers have found that sneaker sperm are bigger and travel in swarms; they will cluster not only with other sneaker sperm but but with consort sperm and even sperm from a breed of starfish. Figuring they might be attracted to a chemical being released by the other sperm, like CO2, the researchers did experiments in which they released C02 bubble into a tube and found that sneaker sperm “swarmed around it,” while consort sperm did not. Why C02 attracts the sneaker sperm is uncertain but one theory is that eggs may release C02.
Bottom line: squids should probably have their own soap opera, Tentacle Hospital or something. I’d watch it.
4. Animal Adaptations
So squid sperm is pretty fascinating but lots of other animals have intriguing sperm and insemination habits as well.
* Jennifer Welsh of LiveScience reports that the mallard duck has sperm that can kill bacteria and the brighter the bill the stronger the antibacterial effect, thus enabling females to avoid a sexually transmitted pathogen and identify males with better sperm,"
says Melissah Rowe of the University of Oslo.
* Science Magazine reports that moss shoots attract insects -- springtails and mites -- which then carry moss sperm and help fertilization like insects pollinating flowers.
* Christine Dell’Amore of National Geographic reports that some sea creatures like jellyfish, barnacles and sponges do what is known as “spermcasting,” sending their sperm out into the water for females to take, in other words, when it’s time, they just go out and pick up some fertilizer.
* The barnacle, Dell’Amore writes, is a special case: it has the biggest penis in the animal kingdom relative to its size and because it can’t move once it’s glued itself somewhere it uses its super-long wiener and “random penis movements” to seek out partners and deposit sperm in their mantle cavity (don’t we all know a guy like that?). If you think that’s nasty and wish to tell a barnacle to go fertilize itself, well, they already do. “Most barnacles are hermaphrodites though they tend to lean toward one gender,” Dell’Amore writes, but they are capable of self-fertilization.
* The grossest animal kingdom sperm transfer has to be the province of bed bugs. The male of the species has a saber-like penis which he uses to stab the female in the abdomen, releasing sperm into her bloodstream -- her reproductive system is used exclusively for egg-laying says this PBS Gross Science Video. It’s known as “traumatic” insemination, writes Alasdair Wilkins of io9 and all seems slightly less horrid when Isabella Rossellini puts on a bed bug costume and acts it out for you.