Don’t let the bed bugs bite
January 30, 2009
They hide from the sunlight and come out at night to suck people’s blood. And the scariest part of all: They’re real.
Check out my very first cover story in the Indiana Daily Student about bed bugs!
To fight or not to fight: lessons from ants
January 23, 2009
All social organisms encounter conflict at some point in their lives. How they deal with it varies greatly across the animal kingdom, ranging from overtly aggressive great whites to the gentle giants known as whale sharks. Most strategies, however, fall somewhere in between, taking context into account for each competitive encounter.
Location, for example, can have a large impact on the escalation of a fight. Are you more willing to fight for a girl in 
the comfort of your favorite hometown pub or on the road in an intimidating biker bar?
Similarly, competitor familiarity may influence the outcome of the contest: are you more likely to fight for her with your friend or a stranger?
Furthermore, the perceived value of a resource often plays a big part in how voraciously an individual will fight for it, with more valuable things warranting extra effort. How hot is she really?
Finally, how your opponent behaves is also likely to affect your behavior. Perhaps one punch to the stomach will make you change your mind about the whole situation.
A recent study out of the University of Utah demonstrates that two closely related species of ants (Formica xerophila and F. integroides) take all of these factors into account when competing with each other for control of trees filled with food-providing bugs known as aphids. However, the two species appear to have different strategies when it comes to determining the intensity with which they will fight to defend their territories.
In this experiment, ants were pitted against a member of the other species either on the trees they were defending, in their home nests, or in a neutral arena. The ants were either from neighboring colonies or distant colonies, in which case it was unlikely that they would have ever before encountered one another. Finally, the researchers used glass beads that were chemically similar to the ants to simulate an intruder while eliminating any behavioral cues that are inherent in the live ant trials.
Both species of ants fought more aggressively when the contest took place on their own territory as opposed to the neutral arena. In addition, both species fought more aggressively when defending their nests, the more valuable resource, than when defending their trees. However, while F. xerophila fought more intensely against strangers than neighboring individuals regardless of competitor behavior (i.e., regardless of whether their competitor was a glass bead or a live ant), F. integroides only fought strangers more aggressively only when fighting a live ant.
The researchers conclude from this finding that F. integroides acts aggressively towards its competitor only when its competitor acts aggressively towards it. This reciprocity approach, known as Tit-for-Tat, was popularized in 1979 when a political science professor named Robert Axelrod was theorizing about the evolution of cooperation. He framed his questions about cooperation in a variation of a classic game theory problem known as the Prisoner’s Dilemma, and set about to determine the conditions under which cooperation would evolve.
The Prisoner’s Dilemma (PD) poses the following hypothetical situation:
Two suspects are arrested by the police. The police have insufficient evidence for a conviction, and, having separated both prisoners, visit each of them to offer the same deal. If one testifies (defects) for the prosecution against the other and the other remains silent, the betrayer goes free and the silent accomplice receives the full 10-year sentence. If both remain silent, both prisoners are sentenced to only six months in jail for a minor charge. If each betrays the other, each receives a five-year sentence. Each prisoner must choose to betray the other or to remain silent. Each one is assured that the other would not know about the betrayal before the end of the investigation. How should the prisoners act? (Taken from Wikipedia.com)
In a completely selfish world, it is always to the prisoners’ advantage to rat out their accomplice (defect). Regardless of how the other prisoner acts, defecting will always result in a shorter jail sentence: 5 years instead of 10 years if the other prisoner defects as well, or no time at all instead of 6 months if the other prisoner remains silent (cooperates).
However, if this situation were to arise repeatedly over the lifetimes of the prisoners, the decision may not be so simple. It may be to their advantage to remain silent, both suffer a 6-month sentence, but remain loyal to each other so that they are able to work together again in the future. In other words, while short-term thinking will always lead both prisoners to defect, there may be a long-term benefit to cooperating.
This is exactly what Axelrod proposed: what is the best strategy of defecting/cooperating individuals should employ when involved in repeated PD interactions. He called this new game the Iterated Prisoner’s Dilemma (IPD) and invited game theorists all over the world to develop strategies to compete in a computer-simulated tournament of 200 iterations of PD interactions.
After receiving 14 submissions in the form of computer algorithms, Axelrod pitted the strategies against each other in a round robin tournament. The winner, the strategy that obtained the highest score (or the shortest prison sentence), was the simplest of them all: Tit-for-Tat, submitted by Anatol Rapoport, a Russian-born mathematical psychologist from the University of Toronto.
Tit-for-Tat has only two rules: 1) cooperate in the first round, and 2) on each successive round, repeat the behavior of your opponent from the round before. Thus, the Tit-for-Tat strategy, which takes the behavior of the other individual into account, can be thought of as cooperation based on reciprocity.
Since this tournament, there have been numerous examples of Tit-for-Tat-like strategies in nature. From fish to birds to primates, social organisms are often observed cooperating with each other, particularly if they’ve been helped by the same individuals in the past.
Most of these examples, however, are framed in terms of cooperation. Examples of Tit-for-Tat strategies used in competitive interactions are harder to come by. The ant story described above is not only an excellent example of such a fighting strategy, but it is the first study to document such a strategy in competitions between two different species, as opposed to conflicts with members of the same species.
So to fight or not to fight…it’s still a difficult decision that depends on a variety of factors. But maybe these ants have the right idea: wait to see what your opponent does before diving head first into an potentially painful and unnecessary brawl.
Notes
For more on the Prisoner’s Dilemma
For more on the Tit-for Tat strategy
For Axelrod’s original paper written in collaboration with WD Hamilton: The Evolution of Cooperation
Why can’t we tickle ourselves?
January 17, 2009
Neuroscientist Sarah Blakemore explains. Interesting idea, but I beg to differ that tickling is a “pleasant” sensation.
Love Potion ‘09
January 14, 2009
In one fell swoop, a neuroscientist may have answered two age-old questions: for men, how do I make her fall in love with me? For women, why does he keep staring at my breasts? Dr. Larry Young of Yerkes Primate Research Center at Emory University published an impressively broad theory on love in last week’s issue of Nature, likening love to a drug that may be reproduced as a kind of real life love potion.
Studying monogamous rodents known as prairie voles, Young boils love down to a series of chemical reactions in the brain that can be studied, understood, and even manipulated.
In females, a hormone called oxytocin is released during mating, which floods the brain and interacts with the reward and reinforcement center. This reward system is driven by dopamine, and just like nicotine, cocaine, and heroine, the result is a feeling of euphoria and the potential for addiction.
Young believes this mechanism is an evolutionary extension of the mother-infant bond that is much more common among mammals that a lasting bond between partners. Oxytocin is also released in females during labor, delivery, and nursing, and is believed to be a major stimulus of motherly love.
It is this connection between romantic and maternal love that may explain men’s fascination with breasts. Originally associated with childbirth and breast feeding, stimulation of the cervix and nipples during sex still results in an impressive release of oxytocin in the brain, which may strengthen the emotional connection both partners feel.
For men, another hormone known as vasopressin, also activated by sex, appears to play a dominant role in the formation of social bonds. For example, variation in the number of vasopressin receptors expressed in the brain — and thus how sensitive the brain is to the release of the hormone — affects the likelihood of marriage and marital success in men.
In addition to its intended purpose of developing drugs to improve the social skills of autism and schizophrenia suffers, the implications of Young’s work include such controversial creations as magical love potions to whisk her off her feet.*
Previous studies have already demonstrated that a squirt of oxytocin up the nose increases trust between people and better tunes them in to one another’s emotions. Companies such as Enhanced Liquid Trust have attempted to market a similar oxytocin-rich concoction as date-enhancing cologne. While Young has his doubts about the effectiveness of such a product, he does suggest a possible role for an oxytocin spray in mending wounded marriages (in conjunction with marriage counseling, that is).
The obvious downside to such technology is the looming possibility that “an unscrupulous suitor could slip a pharmaceutical ‘love potion’ in our drink,” as Young puts it. In addition, the drug’s short-lasting effects certainly present the opportunity for an unwanted addiction, even among knowing users. But caution advised, the possibility for greatness exists. After all, can there ever really be too much love in this world?
*Or in John Tierney’s misanthropic opinion, this research may be better served by the production of a love vaccine.
Notes:
For more on Larry Young’s theory, see the original Nature article.
Apple peels? The Sooners are sold
January 6, 2009
“An apple a day keeps the doctor away.” “Eat an apple on going to bed, and you’ll keep the doctor from earning his bread.” While these catchy proverbs may be stretching the truth a bit — given the uncertain nature of our world, apples may not be a reliable replacement for your family’s health insurance plan – they are founded in fact. It’s no secret that apples are good for you, and their many health benefits have long prompted parents and the USDA alike to encourage the consumption of this delicious fruit.
The new news, then, is not that apples are healthy, but that most of their nutritional value lies in and just under the peel. For the last nine years, Cornell associate professor Rui Hai Liu has been conducting research to demonstrate that the benefits of apples, such as decreased risks of cancer and cardiovascular disease, can actually be found in the peel.
The evidence was so convincing, Liu decided to patent a process for removing and drying apples peels, forming a powered product containing all the valuable nutrients of intact apples. This product can be added to make a variety of other foods healthier, including, somewhat illogically, applesauce.
Jim Leahy (pictured on right), founder of Leahy Orchards, the fourth biggest applesauce producer in North America, was impressed by Liu’s research. Having been in the apple business for nearly 30 years, Leahy has always been a believer in the goodness of apples, but it was the new evidence about the benefits of apple peels that prompted him to team up with Dave Copeland to start AppleBoost Products Inc., producing and distributing products enhanced with dried apple peel.
Anecdotal evidence regarding anti-inflammatory properties of dried apple peel powder (DAPP) quickly attracted the attention of professional athletes, including major league baseball pitchers, who were among the first to try it. Leahy and Copeland took notice and decided to use this trend to their advantage. They began marketing their products to athletes by manufacturing DAPP-supplemented organic applesauce in convenient, portable packages, known as AppleBoost tubes.
The AppleBoost tubes debuted last August when the U.S. Olympic Committee doled out 6,000 of the snacks to American Olympians and their coaches on their way to China. More recently, AppleBoost made a large sale to the Oklahoma Sooners, scheduled to compete in the BCS national title game on January 8.
Under the advice of Jerry Schmidt, head strength and conditioning coach at the University of Oklahoma, the Sooners ordered 3,000 AppleBoost tubes, portable packages of the DAPP-supplemented applesauce, or ‘inside-out applesauce,’ as Schmidt puts it. The tubes were distributed to players at practices leading up to the national championship game.
High-performance athletes of any sport are under a tremendous amount of press, both on and off the field. Dave Ellis, a sports dietician advising the Sooners football team this week, think that such natural products as AppleBoost provide many advantages over vitamins and other dietary supplements alone.
More research is required to detail the effects of the apple peel supplement on the health and performance of dedicated athletes as well as the general benefits of apple peel consumption, but the evidence is mounting: from heart disease and cancer prevention to decreasing cholesterol and lower respiratory problems, the list of apple advantages is growing rapidly. It’s no wonder Johnny Appleseed never got sick.
For a slide show on the apple peeling process, see here.
Summing up 2008…in photos
January 1, 2009
Happy New Year! Check out National Geographic’s Best Science Images of 2008.
