Phintella vittata: All upside-down and ready for love
Courtesy spiderman (Frank)Okay, maybe this isn't as titillating as a big flippered mammal trying to have its way with a bird in a tuxedo, but - hey - it's still about sex.

Scientists have determined for the first time that male jumping spiders (Phintella vittata) are using ultraviolet B (UVB) rays (medium wave) to communicate with their girlfriends and/or potential mates. The use of ultraviolet A (UVA) rays (long wave) in the animal world has been documented before but not UVB. Either way, since ultraviolet light is invisible to the human eye, this tricky technique isn't going to be much use next Saturday night at Larry's Bar and Disco.

But it seems to work as a successful mating strategy for the jumping spider. The researchers doing the study discovered that the male Phintella reflected the UVB rays from their bodies, and that the female objects of their affection were more likely to get it on with those sweet-talkers who could do so in the UVB wavelength. There is a video accompanying the source of this story but I found it neither prurient nor even revealing of the UVB ray method.

However, I did find some really great video of spider courtship behavior that’s worth watching. I’m not sure it’s the same species of jumping spider, but it doesn't matter. What's really interesting is how the audio has been amplified making spiderboy's love tango seem much more mechanical than biological.

I don't know how any of this helps those of you using Match.com or any other dating service, but if you think you need more information about ultraviolet spider love, go here.

You can also check out the journal Current Biology where the study results have been published.

Tags : spiders, sex, reproduction, mating, courtship

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Palau reef: where the party gets started
Courtesy zolas boxOver the next few days, the Palau reef in the West Pacific will experience a frenzy of activities as the reefs' coral denizens partake in their annual mating ritual. Although there won't be any of the usual Spring Break antics such as wet t-shirt or bikini contests, excessive drinking, or stupid male shenanigans, one thing there will be is lots and lots of rampant reproduction.

Just after sunset tonight, or perhaps tomorrow or maybe even the next night, billions upon billions of the coral colonies' eggs and sperm will be unleashed in cute little orange and pink packages that will rise to the surface where they'll lose their inhibitions, burst open, dance and intermingle under the moonlight, and develop into billions of coral larvae. If conditions are right the sheer number of the event's participants can sometimes form huge slicks on the surface that can be seen from space. In the end most of the spawn or larvae gets eaten before it develops fully, but since there's so many of them in the first place, it doesn't really matter.

Anyway, a few days later, any surviving coral larvae will float exhausted to the sea bottom in hopes of attaching themselves to some good solid structure where they develop into baby coral polyps, thus adding more coral to the reef, and living happily ever after. Sounds wonderful, doesn't it?

The 300 island archipelago making up the republic of Palau is located 155 miles above the equator about 550 miles east of the Philippines. The reefs in the vicinity are in good condition ecologically, but the annual spawning has attracted scientists from Great Britain, Australia, and the Philippines, who are in Palau to gather "seeding" material for other less fortunate coral reefs.

The research team won't be using spawning material from the open reefs but instead will harvest it from pieces of coral they've collected and keep in a controlled laboratory environment at the Palau International Coral Reef Center. The larvae from the experiment are then transplanted into a suitable environment conducive to reef-building.

With many of the world's coral reef environments suffering from the effects of pollution, over-fishing, and other factors, the researchers hope seeding damaged reefs with the harvested spawn from healthier ones will help restore the fragile ecosystems.

STORY SOURCE
BBC website

Tags : reproduction, oceans, mass reproduction, environment, coral reef, climate change, sex, spawning

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I've noticed a lot of dead fledglings and raided nests lately. Sometimes, mixed in with all the broken eggshells, I find an unhatched baby bird. And that got me wondering: are grocery store eggs fertilized? How come you never come across one with an embryo or a little chicken inside? If they're not, why does a chicken spend the energy required to produce unfertilized eggs?

Egg (and chicken): (Photo by Peter Cooper)

When you google "are chicken eggs fertilized?" you get a lot of responses. Guess lots of other people had the same question.

The answer is that chickens will lay eggs even when they've had no contact with a rooster. According to the "Ask a Scientist" feature of the Howard Hughes Medical Institute,

"If an egg has been fertilized, then the embryo inside has already divided several times but remains a group of unspecialized cells [at the time the egg is laid]. When the egg is incubated at about 37 to 38 °C, the embryonic cells differentiate to form a chick, which will hatch after 21 days. If the egg has not been fertilized, then the oocyte [or egg cell] within will never grow or divide, and the egg will never hatch. The eggs you buy at the supermarket are eggs that have never been fertilized.

Domestic chickens lay one egg every 26 to 28 hours (about one egg a day) for a period of 4 to 6 days. In between periods of egg laying, the hen rests. Wild birds may rest for months before laying more eggs, but domestic hens, specially bred for abundant egg production, may rest for as little as 1 day between egg-laying periods."

In commercial egg operations, hens are kept away from roosters, and the eggs are collected as they're laid. Chickens raised to produce eggs only need to mate to replace hens that get too old to lay eggs.

Sometimes you come across a grocery store egg that contains a blood spot. I was told, as a child, that a blood spot indicated a fertilized egg. But that's not so, according to the American Egg Board. Instead,

" Contrary to popular opinion, these tiny [blood] spots do not indicate a fertilized egg. Rather, they are caused by the rupture of a blood vessel on the yolk surface during formation of the egg or by a similar accident in the wall of the oviduct. Less than 1% of all eggs produced have blood spots.

Mass candling methods reveal most eggs with blood spots and those eggs are removed but, even with electronic spotters, it is impossible to catch all of them. As an egg ages, the yolk takes up water from the albumen to dilute the blood spot so, in actuality, a blood spot indicates that the egg is fresh. Both chemically and nutritionally, these eggs are fit to eat. The spot can be removed with the tip of a knife, if you wish."

What about those weird white stringy bits you see when you crack an egg? The American Egg Board says they're called chalazae:

"[Chalazae (singular=chalaza) are] ropey strands of egg white which anchor the yolk in place in the center of the thick white. They are neither imperfections nor beginning embryos.

The more prominent the chalazae, the fresher the egg. Chalazae do not interfere with the cooking or beating of the white and need not be removed, although some cooks like to strain them from stirred custard."

Here's a neat site about the structure of a chicken egg.

And another one about how a hen lays an egg.

Egg trivia

And a bunch of other resources about chickens and eggs.

Tags : sex, reproduction, eggs, chickens, birds, animals, no Rooster, no, chicken reproduction, good man was looking for that answer for ages ! i was begining to think it was a secret or somethin, Why would a grown chicken all of a sudden lay a real tiny egg?

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