(Press-News.org) Researchers have experimentally shown that some species of reef fish will enact punishment on the parasitic saber-tooth blennies that stealthily attack them from behind and take a bite, even though their behavior offers no immediate gain. The study, published online on November 4 in Current Biology, a Cell Press publication, shows that punishment ultimately serves all members of the reef fish species well.
In future attacks, blennies are more likely to go after "free-riding" individuals that don't take the time or expend the energy to punish their enemies, the researchers show, suggesting that reef fish punish blennies for reasons that are self-serving. Their self-serving behavior nonetheless creates a "public good." When given a choice, blennies are more apt to switch to another species for their next attack after their previous fare has punished them.
"Our study shows that public goods may arise due to self-serving behavior and without any consideration of the benefits to other group members," said Andrea Bshary of the University of Neuchâtel in Switzerland.
Cooperation in groups can be difficult to explain, since it would seem that "free riders" would win out as they take advantage of the efforts of their peers without contributing themselves. Human studies have explained this conundrum in two ways. Those who contribute may gain from the positive reputation it affords them, which may increase others' willingness to help them at another time. Alternatively, people might cooperate if cheaters can be punished. That raises another question: When does it make sense to punish, given that punishment has immediate costs to both the punisher and the punished?
To explore that question, Bshary and her colleague Redouan Bshary turned to scalefin anthias and the blennies they are known to chase. In this case, it was clear that the reef fish couldn't be acting out of concern for their close kin, because the shoaling fish are generally unrelated to one another.
In laboratory tests, the researchers showed that blennies were less likely to target a colored Plexiglas plate that had earlier chased them off than one that didn't. This showed the chasing behavior to be a bona fide example of punishment; chasing blennies has no immediate benefit, because the parasites almost always bite once per attack. The punishment instead leads to future gains as blennies become less likely to attack punishers.
In observational studies in a natural setting, the researchers found that punishment increased the likelihood that blennies would go for another species in their next attack. This means that all members of a species win when one of them punishes a blenny. Finally, the researchers showed in experiments that at least some blennies could tell the difference between look-alike pairs of plates in which one "punished" them and the other did not, and they would selectively bite nonpunishers. As a result, free riders are at a disadvantage.
The findings in fish suggest that humans, too, might sometimes appear to work together in the real world for reasons that are directly self-serving at their core, the researchers say. They point out that their study differs in an important regard from standard tests of game theory in humans in that the blennies interacted with only one individual of their own choosing. In human experiments, people often interact in groups.
"As a consequence," the researchers write, "it is always clear which individual of a shoal has to punish the blenny for its cheating. A victim cannot expect others to do the punishment, because they did not have a negative experience. We think that such conditions often apply to humans as well, in which punishment is a self-serving response to being cheated while benefiting the community as well. A person whose house gets broken into or who gets attacked by robbers will have to take action (call the police or fight back) even though all the neighbors may profit from this."
###
The researchers include Andrea Bshary, and Redouan Bshary, of University of Neuchatel, Institute of Biology, Neuchatel, Switzerland.
END
The adult human skeleton undergoes constant remodeling, with new bone forming at sites that have been broken down by a precise process called resorption. During remodeling, skeletal stem cells are recruited to resorption sites and directed to differentiate into bone-forming cells. Osteoporosis, a condition characterized by weak and fragile bones, develops when there is an imbalance in the remodeling process and more bone is lost than replaced. Now, new research published by Cell Press in the November issue of the journal Cell Stem Cell uncovers a mechanism that may guide ...
Although human and chimpanzee immune systems have many identical components, this is not the case for the family of killer cell immunoglobulin-like receptors (KIR) controlling white blood cells known as natural killer (NK) cells. Published in the open-access journal PloS Genetics on November 4, a paper by Stanford University researchers describes qualitative KIR differences, acquired after humans and chimpanzees separated 6 million years ago and mainly a consequence of innovation in the human line. These differences open up an exciting avenue for explaining the differential ...
A new study published today shows a genetic 'battle of the sexes' could be much harder to resolve and even more important to evolution than previously thought.
This battle, observed across many species and known as intralocus sexual conflict, happens when the genes for a trait which is good for the breeding success of one sex are bad for the other – sparking an 'evolutionary tug-o-war' between the sexes.
It has previously been thought these issues were only resolved when the trait in question evolves to become sex-specific in its development – meaning the trait only ...
ASDs include a range of neurodevelopmental conditions that are being diagnosed at an increasing rate. The Center for Disease Control and Prevention estimates that ASD currently affects 1 in 110 people. The prevalence of schizophrenia, with a diagnostic rate of 1 in 100 to 1 in 20, is similar. ASD and schizophrenia affect males more often than females, and both are thought to have a strong and overlapping genetic component. "The genetic overlap between ASD and schizophrenia, both of which have a high heritability, has been the focus of several recent studies; however, no ...
A research team led by Teh-hui Kao, professor of biochemistry and molecular biology at Penn State University, in collaboration with a team lead by Professor Seiji Takayama at the Nara Institute of Science and Technology in Japan, has discovered a large suite of genes in the petunia plant that acts to prevent it from breeding with itself or with its close relatives, and to promote breeding with unrelated individuals. In much the same way that human inbreeding sometimes results in genetic disease and inferior health, some inbred plants also experience decreased fitness, and ...
Tiny variants in a protein that alerts the immune system to the presence of infection may underlie the rare ability of some individuals to control HIV infection without the need for medications. In a report that will appear in Science and is receiving early online release, an international research team led by investigators from the Ragon Institute of Massachusetts General Hospital (MGH), MIT and Harvard and from the Broad Institute of MIT and Harvard describe finding that differences in five amino acids in a protein called HLA-B are associated with whether or not HIV-infected ...
A registry of health care information on patients with mild to moderate chronic kidney disease (CKD) could help physicians improve care for affected individuals, according to a study appearing in an upcoming issue of the Clinical Journal of the American Society Nephrology (CJASN). The results suggest that officials could use such a registry to develop a national surveillance system to identify and track various aspects of CKD.
The incidence and health care costs of CKD are growing. A national reporting system that collects health care details on dialysis patients and ...
Today, individuals with lupus nephritis benefit from better treatments than a decade ago, according to a review appearing in an upcoming issue of the Journal of the American Society Nephrology (JASN). The article suggests that patients with the disease can now live full lives without suffering from many treatment-related side effects that plagued them in the past. In the future, patients will likely experience additional benefits from treatment strategies currently being explored in clinical trials.
Individuals with the autoimmune disease systemic lupus erythematosus ...
Lasofoxifene statistically reduced the overall risk of breast cancer, as well as ER positive invasive breast cancer in postmenopausal women with low bone density, according to a study published online in The Journal of the National Cancer Institute.
Lasofoxifene is a SERM, or selective estrogen receptor modulator, that, like tamoxifen, blocks the effects of estrogen in breast tissue. Another SERM, raloxifene, has been shown to reduce breast cancer risk. In the Postmenopausal Evaluation and Risk-Reduction with Lasofoxifene (PEARL) trial, a double-blind, placebo-controlled, ...
CAMBRIDGE, Mass. -- Researchers at Harvard University say America's obesity epidemic won't plateau until at least 42 percent of adults are obese, an estimate derived by applying mathematical modeling to 40 years of Framingham Heart Study data.
Their work, published this week in the journal PLoS Computational Biology, runs counter to recent assertions by some experts that the obesity rate, which has been at 34 percent for the past five years, may have peaked. An additional 34 percent of American adults are overweight but not obese, according to the federal government's ...
