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Loving, Fighting, Peeing: The Sex Lives of Crayfish

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When I'm not blogging for mental_floss, I can usually be found wearing bright orange rubber pants and gutting, cutting and selling fish at my local Whole Foods (and winning awards for it). Sometimes, my two worlds collide and I find some scientific research involving my ocean-dwelling friends that begs for a blog post. This is one of those times.

Let's pretend, all evidence to the contrary aside, that I am a beautiful woman and I want to have children, right here and right now. What do you think is the best way to go about communicating that to men? Make eyes at them from across the room? Approach and aggressively flirt?

If I were a lady crayfish (crawfish, crawdad, mudbug, whatever you prefer to call them), my plan of action would be to urinate all over the place and start throwing punches.

Female crayfish take "playing hard to get" to a whole new level. Naturally, they want the strongest, fittest mates available to produce exceptional offspring. But crayfish are in a tough spot when it comes to discerning the fitness of potential mates. Simply checking the guys out doesn't provide much info, and chemical cues aren't always reliable. So the simplest and best way for a female to find the best mate is to test males in claw-to-claw combat herself.

How does she get the ball rolling? By peeing.

In some animals, the female initiates mating with chemical stimuli, informing suitors of her receptivity to sex. In crayfish, these stimuli happen to be in the urine. Fiona Berry and Thomas Breithaupt from the University of Hull recently published the results of a study on these urine-based chemical signals. In their experiment, male and female American signal crayfish (Pacifastacus leniusculus) were introduced to each other in a tank after being blindfolded (to exclude visual disturbance from the researchers) and injected with a fluorescent dye that accumulated in the bladder (to visualize urine).

Berry and Breithaupt found that under normal conditions (well, except for the blindfolds), the females would urinate to attract the males and then respond aggressively when they approached. The females would give up the fight only if a male was able to flip her over and deposit his sperm. When females were kept from releasing urine (by the blocking of the nephropores), though, no mating behavior was observed.

Artificial introduction of female urine, via a syringe placed in the tank, re-established normal mating attempts, demonstrating that there is a sex-specific component in the females' urine that both signals aggression and elicits mating behavior (males also use urine to signal aggression when fighting other males). The mixed aggro-sexual message that the urine communicates should, the researchers say, favor strong, high-quality males.

Aside from making our own sex lives seem normal in comparison, the lessons learned from this study could aid the UK in its battle against the signal crayfish, which is an invasive species in English rivers and carries a fungus that's lethal to the country's native white clawed crayfish (Austropotamobius torrentium).

Citation: Berry, F. and Breithaupt, T. (2010). "To signal or not to signal? Chemical communication by urine-borne signals mirrors sexual conflict in crayfish." BMC Biology 8:25. DOI:10.1186/1741-7007-8-25

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6 Radiant Facts About Irène Joliot-Curie
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Hulton Archive/Getty Images

Though her accomplishments are often overshadowed by those of her parents, the elder daughter of Marie and Pierre Curie was a brilliant researcher in her own right.

1. SHE WAS BORN TO, AND FOR, GREATNESS.

A black and white photo of Irene and Marie Curie in the laboratory in 1925.
Irène and Marie in the laboratory, 1925.
Wellcome Images, Wikimedia Commons // CC BY 4.0

Irène’s birth in Paris in 1897 launched what would become a world-changing scientific dynasty. A restless Marie rejoined her loving husband in the laboratory shortly after the baby’s arrival. Over the next 10 years, the Curies discovered radium and polonium, founded the science of radioactivity, welcomed a second daughter, Eve, and won a Nobel Prize in Physics. The Curies expected their daughters to excel in their education and their work. And excel they did; by 1925, Irène had a doctorate in chemistry and was working in her mother’s laboratory.

2. HER PARENTS' MARRIAGE WAS A MODEL FOR HER OWN.

Like her mother, Irène fell in love in the lab—both with her work and with another scientist. Frédéric Joliot joined the Curie team as an assistant. He and Irène quickly bonded over shared interests in sports, the arts, and human rights. The two began collaborating on research and soon married, equitably combining their names and signing their work Irène and Frédéric Joliot-Curie.

3. SHE AND HER HUSBAND WERE AN UNSTOPPABLE PAIR.

Black and white photo of Irène and Fréderic Joliot-Curie working side by side in their laboratory.
Bibliothèque Nationale de France, Wikimedia Commons // Public Domain

Their passion for exploration drove them ever onward into exciting new territory. A decade of experimentation yielded advances in several disciplines. They learned how the thyroid gland absorbs radioiodine and how the body metabolizes radioactive phosphates. They found ways to coax radioactive isotopes from ordinarily non-radioactive materials—a discovery that would eventually enable both nuclear power and atomic weaponry, and one that earned them the Nobel Prize in Chemistry in 1935.

4. THEY FOUGHT FOR JUSTICE AND PEACE.

The humanist principles that initially drew Irène and Frédéric together only deepened as they grew older. Both were proud members of the Socialist Party and the Comité de Vigilance des Intellectuels Antifascistes (Vigilance Committee of Anti-Fascist Intellectuals). They took great pains to keep atomic research out of Nazi hands, sealing and hiding their research as Germany occupied their country, Irène also served as undersecretary of state for scientific research of the Popular Front government.

5. SHE WAS NOT CONTENT WITH THE STATUS QUO.

Irène eventually scaled back her time in the lab to raise her children Hélène and Pierre. But she never slowed down, nor did she stop fighting for equality and freedom for all. Especially active in women’s rights groups, she became a member of the Comité National de l'Union des Femmes Françaises and the World Peace Council.

6. SHE WORKED HERSELF TO DEATH.

Irène’s extraordinary life was a mirror of her mother’s. Tragically, her death was, too. Years of watching radiation poisoning and cancer taking their toll on Marie never dissuaded Irène from her work. In 1956, dying of leukemia, she entered the Curie Hospital, where she followed her mother’s luminous footsteps into the great beyond.

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You Can Now Order Food Through Facebook
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After a bit of controversy over its way of aggregating news feeds and some questionable content censoring policies, it’s nice to have Facebook roll out a feature everyone can agree on: allowing you to order food without leaving the social media site.

According to a press release, Facebook says that the company decided to begin offering food delivery options after realizing that many of its users come to the social media hub to rate and discuss local eateries. Rather than hop from Facebook to the restaurant or a delivery service, you’ll be able to stay within the app and select from a menu of food choices. Just click “Order Food” from the Explore menu on a desktop interface or under the “More” option on Android or iOS devices. There, you’ll be presented with options that will accept takeout or delivery orders, as well as businesses participating with services like Delivery.com or EatStreet.

If you need to sign up and create an account with Delivery.com or Jimmy John’s, for example, you can do that without leaving Facebook. The feature is expected to be available nationally, effective immediately.

[h/t Forbes]

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