Facebook makes us feel good about ourselves: study

People love social networks. That's the obvious conclusion from Facebook's 900 million active users and its current standing as one of the most visited sites on the web, second only to Google. New research from the University of Georgia finds what people may really "like" about social networking are themselves.

"Despite the name 'social networks,' much user activity on networking sites is self-focused," said Brittany Gentile, a UGA doctoral candidate who looked at the effects of social networks on self-esteem and narcissism.

According to the research, published online this month by the journal Computers in Human Behavior, the 526 million people who log on to Facebook every day may be boosting their self-esteem in the process.

Gentile, along with UGA psychology professor Keith Campbell and San Diego State University professor Jean Twenge, asked college students to either edit their social networking page on MySpace or Facebook or to use Google Maps. Those who edited their MySpace page later scored higher on a measure of narcissism, while those who spent time on their Facebook page scored higher on self-esteem.

"Editing yourself and constructing yourself on these social networking sites, even for a short period of time, seems to have an effect on how you see yourself," said Campbell, who heads the department of psychology in the UGA Franklin College of Arts and Sciences and co-authored the book "The Narcissism Epidemic: Living in the Age of Entitlement." "They are feeling better about themselves in both cases. But in one they are tapping into narcissism and in the other into self-esteem."

MySpace reported 25 million users as of June 2012. MySpace users participated in the experiment in 2008, when the site had 115 million active users. Facebook users participated in 2011. On both MySpace and Facebook, students scoring higher in narcissism reported having more friends on the site.

A total of 151 students, ages 18-22, completed the Narcissistic Personality Inventory as a part of the study.

"The NPI measures trait narcissism, which is a stable personality trait," Gentile said. "But spending 15 minutes editing a MySpace page and writing about its meaning was enough to alter self-reports of this trait, suggesting that social networking sites may be a significant influence on the development of personality and identity."

The differences in site format may be one reason why MySpace led to higher narcissism whereas Facebook merely produced higher self-esteem.

"The two sites operate differently," Gentile said. "On MySpace you don't really interact with other people. The pages resemble personal webpages, and a lot of people have become famous on MySpace, whereas Facebook has a standard profile and a company message that sharing will improve the world."

Several previous studies found increases over the generations in both self-esteem and narcissism. These new experiments suggest the increasing popularity of social networking sites may play a role in those trends.

"Social networking sites are a product and a cause of a society that is self-absorbed," Campbell said. "Narcissism and self-esteem began to rise in the 1980s. Because Facebook came on the scene only seven years ago, it wasn't the original cause of the increases. It may be just another enforcer."

Social networking should not be seen as an answer to building self-esteem, he said, but the fact that people may get a jolt when logging on doesn't mean they should stop either.

"Ideally, you get self-esteem from having strong relationships and achieving goals that are reasonable and age-appropriate," Campbell said. "Ideally, self-esteem is not something you should take a short cut to find. It is a consequence of a good life, not something you chase."

More information: For the full research article, see http://www.science … 563212001409

Provided by University of Georgia

"Facebook makes us feel good about ourselves: study." June 26th, 2012.http://medicalxpress.com/news/2012-06-facebook-good.html

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Robert Karl Stonjek

New way to view atoms

MONASH UNIVERSITY

Share on print A new high-tech method for imaging the electric fields of atoms could lead to advances in areas as diverse as data storage, solar cells and batteries. Research published today in the prestigious journal Nature Physics detailed how physicists from Monash University and Japanese institutions, including the University of Tokyo and the Japan Science and Technology Agency, viewed the electric fields of atoms using a new advanced scanning transmission electron microscopy technique. Electric fields are produced by the electrically charged particles within atoms, known as protons and electrons. The electrical forces between the positively and negatively charged particles play an important structural role—they hold the atoms together. By visualising the pattern of the fields produced by these charges, scientists will gain further insight into the electrical properties of materials. For instance, manufacturing electric field patterns on small length scales is a route to high-capacity data storage. Co-author Dr Scott Findlay of Monash University's School of Physics said the technique he developed with his Japanese colleagues was a breakthrough. "Electron microscopy is a fast-developing field. Recent advances have let us see where individual atoms sit in a material, but it has been much harder to see their electric fields," Dr Findlay said. The new technique allows the researchers to view electric field patterns by the deflections they induced in a beam of electrons. "It’s like rolling marbles to look for slight slopes in the ground. If the marble deflects to the left, that must be downhill; if the beam of electrons deflects to the left, that must be the direction the field points," Dr Findlay said. Dr Findlay said that viewing materials on the atomic level gave an entirely new perspective. "We're seeing things that we've never seen before. Understanding the behaviour of materials and their electric fields on a very small scale expands what we can do with them," Dr Findlay said. A number of groups internationally had been working on picturing electric fields. Dr Findlay will continue to work with collaborators in Japan to further refine their technique and apply it to developing new materials. Editor's Note: Original news release can be found here.

What is breast cancer in men?

Aside from prostate cancer, did you know that men can also have breast cancer? Know the early warning signs and symptoms.

What is breast cancer in men?

A breast cancer is a malignant tumor that starts from cells of the breast. A malignant tumor is a group of cancer cells that may grow into (invade) surrounding tissues or spread (metastasize) to distant areas of the body. Breast cancer occurs mainly in women, but men can get it, too. Many people do not realize that men have breast tissue and that they can develop breast cancer.

Normal breast structure

To understand breast cancer, it helps to have some basic knowledge about the normal structure of the breasts.

The breast is made up mainly of lobules (milk-producing glands in women), ducts (tiny tubes that carry the milk from the lobules to the nipple), and stroma (fatty tissue and connective tissue surrounding the ducts and lobules, blood vessels, and lymphatic vessels).

Until puberty (usually around 13 or 14), young boys and girls have a small amount of breast tissue consisting of a few ducts located under the nipple and areola (area around the nipple). At puberty, a girl's ovaries make female hormones, causing breast ducts to grow, lobules to form at the ends of ducts, and the amount of stroma to increase. In boys, hormones made by the testicles keep breast tissue from growing much. Men's breast tissue has ducts, but only a few if any lobules.

Like all cells of the body, a man's breast duct cells can undergo cancerous changes. But breast cancer is less common in men because their breast duct cells are less developed than those of women and because their breast cells are not constantly exposed to the growth-promoting effects of female hormones.

The lymph (lymphatic) system of the breast

The lymph system is important to understand because it is one of the ways that breast cancers can spread. This system has several parts.

Lymph nodes are small, bean-shaped collections of immune system cells (cells that are important in fighting infections) that are connected by lymphatic vessels. Lymphatic vessels are like small veins, except that they carry a clear fluid called lymph (instead of blood) away from the breast. Lymph contains tissue fluid and waste products, as well as immune system cells. Breast cancer cells can enter lymphatic vessels and begin to grow in lymph nodes.

Most lymphatic vessels in the breast connect to lymph nodes under the arm (axillary nodes). Some lymphatic vessels connect to lymph nodes near the breast bone (internal mammary nodes) and either above or below the collarbone (supraclavicular or infraclavicular nodes).

It's important to know if the cancer cells have spread to lymph nodes. If they have, there is a higher chance that the cells could have gotten into the bloodstream and spread (metastasized) to other sites in the body. This is important to know when you are choosing a treatment. The more lymph nodes with breast cancer cells (positive lymph nodes), the more likely it is that the cancer might be found in other organs as well. Still, not all men who have positive lymph nodes develop metastases, and in some cases a man can have negative lymph nodes and later develop metastases.

Benign breast conditions

Men can also have some benign (not cancerous) breast disorders.

Benign breast tumors

There are many types of benign breast tumors (abnormal lumps or masses of tissue), such as papillomas and fibroadenomas. Benign breast tumors do not spread outside the breast and are not life threatening. Benign tumors are common in women but are very rare in men.

Gynecomastia

Gynecomastia is the most common male breast disorder. It is not a tumor but rather an increase in the amount of a man's breast tissue. Usually, men have too little breast tissue to be felt or noticed. A man with gynecomastia has a button-like or disk-like growth under his nipple and areola, which can be felt and sometimes seen. Although gynecomastia is much more common than breast cancer in men, both can be felt as a growth under the nipple, which is why it's important to have any such lumps checked by your doctor.

Gynecomastia is common among teenage boys because the balance of hormones in the body changes during adolescence. It is also common in older men due to changes in their hormone balance.

In rare cases, gynecomastia occurs because tumors or diseases of certain endocrine (hormone-producing) glands cause a man's body to make more estrogen (the main female hormone). Men's glands normally make some estrogen, but it is not enough to cause breast growth. Diseases of the liver, which is an important organ in male and female hormone metabolism, can change a man's hormone balance and lead to gynecomastia. Obesity (being extremely overweight) can also cause higher levels of estrogens in men.

Some medicines can cause gynecomastia. These include some drugs used to treat ulcers and heartburn, high blood pressure, and heart failure. Men with gynecomastia should ask their doctors if any medicines they are taking might be causing this condition.

Breast cancer general terms

Here are some of the key words used to describe breast cancer.

Carcinoma

This is a term used to describe a cancer that begins in the lining layer (epithelial cells) of organs such as the breast. Nearly all breast cancers are carcinomas (either ductal carcinomas or lobular carcinomas).

Adenocarcinoma

An adenocarcinoma is a type of carcinoma that starts in glandular tissue (tissue that makes and secretes a substance). The ducts and lobules of the breast are glandular tissue (they make breast milk in women), so cancers starting in these areas are sometimes called adenocarcinomas.

Carcinoma in situ

This term is used for an early stage of cancer, when it is confined to the layer of cells where it began. In breast cancer, in situmeans that the abnormal cells remain confined to ducts (ductal carcinoma in situ, or DCIS). These cells have not grown into (invaded) deeper tissues in the breast or spread to other organs in the body. Ductal carcinoma in situ of the breast is sometimes referred to as non-invasive or pre-invasive breast cancer because it may develop into an invasive breast cancer if left untreated.

When cancer cells are confined to the lobules it is called lobular carcinoma in situ. This is not actually a true pre-invasive cancer because it does not turn into an invasive cancer if left untreated.

Invasive (infiltrating) carcinoma

An invasive cancer is one that has already grown beyond the layer of cells where it started (as opposed to carcinoma in situ). Most breast cancers are invasive carcinomas, either invasive ductal carcinoma or invasive lobular carcinoma.

Types of breast cancer in men

Ductal carcinoma in situ (DCIS)

In DCIS (also known as intraductal carcinoma), cancer cells form in the breast ducts but do not grow through the walls of the ducts into the fatty tissue of the breast or spread outside the breast. DCIS accounts for about 1 in 10 cases of breast cancer in men. It is almost always curable with surgery.

Infiltrating (or invasive) ductal carcinoma (IDC)

This type of breast cancer breaks through the wall of the duct and grows through the fatty tissue of the breast. At this point, it can spread (metastasize) to other parts of the body. At least 8 out of 10 male breast cancers are IDCs (alone or mixed with other types of invasive or in situ breast cancer). Because the male breast is much smaller than the female breast, all male breast cancers start relatively close to the nipple, so they are more likely to spread to the nipple. This is different from Paget disease as described below.

Infiltrating (or invasive) lobular carcinoma (ILC)

This type of breast cancer starts in the breast lobules (collections of cells that, in women, produce breast milk) and grows into the fatty tissue of the breast. ILC is very rare in men, accounting for only about 2% of male breast cancers. This is because men do not usually have much lobular tissue.

Lobular carcinoma in situ (LCIS)

In LCIS, abnormal cells form in the lobules, but they do not grow into the fatty tissue of the breast or spread outside the breast. Although LCIS is sometimes grouped with DCIS as a type of non-invasive breast cancer, most breast specialists think it is a risk factor for developing breast cancer rather than a true non-invasive cancer. As with invasive lobular carcinoma, LCIS is very rare in men.

Paget disease of the nipple

This type of breast cancer starts in the breast ducts and spreads to the nipple. It may also spread to the areola (the dark circle around the nipple). The skin of the nipple usually appears crusted, scaly, and red, with areas of itching, oozing, burning, or bleeding. The fingertips can be used to detect a possible lump within the breast.

Paget disease may be associated with DCIS or with infiltrating ductal carcinoma. It accounts for about 1% of female breast cancers and a higher percentage of male breast cancers.

Inflammatory breast cancer

Inflammatory breast cancer is an aggressive, but rare type of breast cancer. It causes the breast to be swollen, red, warm and tender rather than forming a lump. It can be mistaken for an infection of the breast. This is very rare in men.

Breast Cancer in Men

Although it is a rare form of cancer, breast cancer does occur in men. It is estimated that 1,970 new cases in males will develop in 2010, with 390 deaths. It tends to occur at a later age in men than in women, with the male peak age being 71 years old as opposed to peaks at 51 and 71 years old in women.⁽¹⁾⁽²⁾

Symptoms^(1) (2)

• Painless lump in the breast (over 75% of cases)
• Nipple retraction, discharge, or ulceration
• Painful lump in the breast
• Paget's Disease (only about 1% of cases): This is a rare type of cancer that can appear as a skin rash (dermatitis) around the nipple. Note that this is NOT related to Paget's disease of the bone.

Detection and Diagnosis

Diagnosis of breast cancer in men is generally delayed 6 - 10 months (the time from the onset of symptoms until the patient seeks treatment). This delay is partially due to a) the rarity of the disease and b) a lack of awareness of (suspicion of) the disease by patients and their doctors. Because of this delay, men present with the disease at a later stage than women:

• Stage I - ~40%
• Stage II - ~20%
• Stage III/IV - Over 40%

When symptoms are present, doctors generally use the Triple Test (TT) method to determine stage and treatment plan. The TT is the use of clinical exam, mammography or ultrasound, and fine needle aspiration (FNA) or core needle biopsy (CNB). ⁽²⁾⁽¹⁾ Watch a video about mammography, ultrasound, and/or biopsy.

Mammography has been shown to have a sensitivity of 92% and a specificity of 90% in male breast cancer, but is not used as a screening tool. 

Pathology

Male breast tissue is mostly fat and the lobules needed to form milk are undeveloped. Over 90% of male breast tumors are invasive (infiltrating) ductal carcinoma and ER positive.^(1) (2)

Risk Factors⁽²⁾⁽¹⁾

• Obesity
• Alcohol consumption
• Liver damage or dysfunction
• Testicular abnormality or damage
• Radiotherapy, especially to the chest
• Family history of breast cancer (especially with a BRCA2 mutation)
• Klinefelter's Syndrome

Treatment

Surgery

Simple or modified radical mastectomy and surgical assessment of the lymph nodes are used when cancer is found in its early stages. Assessment of the lymph nodes is accomplished using either axillary dissection or sentinel lymph node biopsy.

Radiotherapy

Males are more likely to receive radiotherapy than females, probably due to the fact that males present with breast cancer at a later stage than females. Radiation dosages used to treat men are generally the standard amounts used to treat women. Radiotherapy has been shown effective in preventing local recurrence in men with breast cancer.⁽³⁾⁽⁴⁾

Systemic Therapy

Because about 90% of men with breast cancer are hormone receptor positive (HR+), treatment with tamoxifen is standard in HR+ men. Men treated with tamoxifen have shown higher overall survival rates. Men may also receive systemic chemotherapy.^(3) (2)

Quality of Life

Men with breast cancer face a different environment than women coping with breast cancer. There is a large amount of information and public support for women. On the other hand there is a lack of information and added stressors for men. Men deal with issues of masculinity and stigmatism in addition to the other physical and emotional concerns that come along with having breast cancer.⁽⁵⁾⁽⁶⁾

Shirdi Saibaba - Jai Jagdish Hare swami Jai Jagdish Hare

Snacking on Raisins Significantly Reduces Overall Post-Meal Blood Sugar Levels

 

New research debuted at the American Diabetes Association’s 72nd Annual Scientific Session suggests eating raisins three times a day may significantly lower postprandial (post-meal) glucose levels when compared to common alternative snacks of equal caloric value.

Raisins have a relatively low glycemic index and contain fiber and antioxidants.

The study was conducted at the Louisville Metabolic and Atherosclerosis Center (L-MARC) by lead researcher, Harold Bays, MD, medical director and president of L-MARC.

The study was conducted among 46 men and women who had not previously been diagnosed with diabetes mellitus, but who had mild elevations in glucose levels. Participants were randomly assigned to snack on raisins or pre-packaged commercial snacks that did not contain raisins or other fruits or vegetables, three times a day for 12 weeks. Findings included:

• Compared to control snacks, raisins significantly decreased mean post-meal glucose levels by 16 percent
• Compared to baseline within group paired analysis, raisins significantly reduced mean hemoglobin A1c by 0.12 percent
• Consumption of the control snacks in the study did not significantly reduce mean post-meal glucose or hemoglobin A1c

“Compared to the snacking control group, the group consuming raisins had a significant statistical reduction in their after-liquid meal blood sugar levels among study participants who had mean baseline fasting glucose levels between 90 and 100 mg/dl.,” said Dr. Bays. “This favorable glucose effect of raisins was further supported by the statistically significant reduction in hemoglobin A1c (a standard test for overall blood sugar control in diabetes mellitus) in the within group comparison to baseline. The within group comparisons from baseline with snacks did not demonstrate a reduction in hemoglobin A1c.”

VIDEO: Raisins and glucose a randomized controlled trial

The study was funded by the California Raisin Marketing Board through a grant to the L-MARC Research Center in Louisville, Kentucky.

“Raisins have a relatively low glycemic index and contain fiber and antioxidants, all factors which contribute to blood sugar control,” said James Painter, Ph.D., R.D., and nutrition research advisor for the California Raisin Marketing Board. “Decreasing blood sugar and maintaining normal hemoglobin A1c levels is important because it can prevent long-term damage to the heart and circulatory system.”

This research is part of a two-part study by L-MARC that looked at raisins and possible impacts to blood pressure and blood sugar levels. The first part of the study announced at the American College of Cardiology’s 61st Annual Scientific Session suggests eating raisins three times a day may significantly lower blood pressure among individuals with slightly higher than normal blood pressure, otherwise known as prehypertension.

Visit www.loveyourraisins.com for further information and summaries of California Raisins’ nutrition research. 

_________

Courtesy MultiVu

Researchers develop new method for analyzing cell function

 Researchers in Finland and Germany have developed an open-source software that will make it significantly easier to process bioimaging data. The software, named BioImageXD, will help in analysing cell and tissue functions.

BioImageXD is a free open-source multi-purpose post-processing tool for bioimaging. The software can be used for simple visualization of multi-channel temporal image stacks to complex 3D rendering of multiple channels at once. Animations of 3D renderings can be created using flying paths or keyframes.

The work to develop the software has been funded by the Academy of Finland (through the FinNano Research Programme), the European Union and Tekes – the Finnish Funding Agency for Technology and Innovation. Version 1.0 of BioImageXD has been accepted for publication in Nature Methods, the top journal in the field.

Among other things, the BioImageXD software is a tool for analysing how molecules move on cell surfaces and how they bond together. With the software, scientists can analyse the composition of cell surfaces, study how cancer cells spread in a three-dimensional environment, or measure how effectively viruses and targeted drugs enter cells. Such calculations have not been possible before.

In recent years, cell and tissue imaging with new, specialised microscopes has considerably advanced research in bioscience and biomedicine. The new methods also allow for studies on living cells. However, the microscopic images are not displayable as such and need to be rendered into three-dimensional models. These 3D renderings carry significant weight as evidence already by themselves, but reliable scientific data also requires numerical values, which can then be used in mathematical calculations. In addition, these calculations must be feasible with extremely large datasets.

So far, the lack of suitable software has clogged up this development. To solve the problem, researchers in Turku, Jyväskylä and Dresden drew up precise specifications for software for processing of imaging data. A key criterion was that the software would be based on the principles of open source, freely available to all researchers.

The work resulted in BioImageXD, a software program that thanks to its versatile and open-source nature has received much positive feedback from hundreds of researchers around the world.

From extensive development to test success 

One of the unique features of BioImageXD is that it can be used to create completely new analysis methods (and users do not even need programming skills), process thousands of images at the same time and analyse millions of molecules. Comparison tests have shown that BioImageXD is faster and more sensitive than other similar programs.

The development of the BioImageXD software began ten years ago in a University of Jyväskylä research team led by Jyrki Heino. Since then, the work has continued through active collaboration between Heino’s team, Varpu Marjomäki’s team and Daniel White from Max Planck Institute of Molecular Cell Biology and Genetics.

The main development has been led by Pasi Kankaanpää, who now works at Turku Centre for Biotechnology as Coordinator of the Cell Imaging Core.

The BioImageXD software will be featured in a special issue of Nature Methods, focusing on the processing of biomedical images.

__________

Courtesy Academy of Finland

For model images and videos on the BioImageXD software, and its use in visualising intracellular molecules, for instance, please contact Pasi Kankaanpää.

More information:

• Coordinator Pasi Kankaanpää (University of Turku), tel. +358 40 522 1090, pkanka@utu.fi
• Professor Jyrki Heino (University of Turku), tel. +358 50 523 8351,jyrki.heino@utu.fi
• Adjunct Professor Varpu Marjomäki (University of Jyväskylä), tel. +358 40 563 4422, varpu.s.marjomaki@jyu.fi

Article: P. Kankaanpää, L. Paavolainen, S. Tiitta, M. Karjalainen, J. Päivärinne, J. Nieminen, V. Marjomäki, J. Heino and D. White (2012). “BioImageXD: an open, general-purpose and high-throughput image-processing platform”. Nature Methods 9: 683-689.

Biologists reveal potential ‘fatal flaw’ in iconic sexual selection study

 

A classic study from more than 60 years ago suggesting that males are more promiscuous and females more choosy in selecting mates may, in fact, be wrong, say life scientists who are the first to repeat the historical experiment using the same methods as the original.

In 1948, English geneticist Angus John Bateman published a study showing that male fruit flies gain an evolutionary advantage from having multiple mates, while their female counterparts do not. Bateman’s conclusions have informed and influenced an entire sub-field of evolutionary biology for decades.

“Bateman’s 1948 study is the most-cited experimental paper in sexual selection today because of its conclusions about how the number of mates influences fitness in males and females,” said Patricia Adair Gowaty, a distinguished professor of ecology and evolutionary biology at UCLA. “Yet despite its important status, the experiment has never been repeated with the methods that Bateman himself used initially, until now.

“Our team repeated Bateman’s experiment and found that what some accepted as bedrock may actually be quicksand. It is possible that Bateman’s paper should never have been published.”

Gowaty’s study was published June 11 in the online edition of Proceedings of the National Academy of Sciences and is scheduled for publication in an upcoming print edition.

The original experiment on Drosophila melanogaster, also known as the common fruit fly, was performed by creating multiple, isolated populations with either five males and five females or three of each gender in a jar. The insects mated freely in the experimental populations, and Bateman examined the children that made it to adulthood. To count the number of adult offspring engendered by each of his original insect subjects, Bateman needed a reliable way to match parents with children.

Nowadays, modern geneticists would use molecular evidence to determine the genetic parentage of each child, but DNA analysis was not available in the 1940s. Instead, Bateman chose his initial specimens carefully, selectingD. melanogaster flies that each had a unique, visible mutation that could be transferred from parent to child, Gowaty said.

The mutations were extreme. Some of the flies had curly wings, others thick bristles, and still others had eyes reduced in size to narrow slits. The outward differences in each breeding subject allowed Bateman to work backward to determine the parentage of some of the fly progeny and to document each mating pair among the original insects. A child with curly wings and thick bristles, for example, could only have come from one possible pairing.

Yet Bateman’s method, which was cutting-edge for its time, had a “fatal flaw,” according to Gowaty.

Imagine the child of a curly-winged mother and an eyeless father. The child has an equal chance of having both mutations, only the father’s mutation, only the mother’s mutation or no mutation at all. In order to know who mated with whom, Bateman used only the children with two mutations, because these were the only ones for which he could specifically identify both the mother and father. But by counting only the children with two mutations, Bateman probably got a skewed sample, Gowaty said. In repeating Bateman’s experiment, she and her colleagues found that the flies with two severe mutations are less likely to survive into adulthood.

Flies use their wings not only to hover but also to sing during courtship, which is why curly wings present a huge disadvantage. Specimens with deformed eyes might have an even tougher time surviving. The 25 percent of children born with both mutations were even more likely to die before being counted by Bateman or Gowaty.

“It’s not surprising that the kids died like flies when they got one dramatic mutation from mom and another dramatic mutation from dad,” she said.

Gowaty found that the fraction of double-mutant offspring was significantly below the expected 25 percent, which means Bateman would have been unable to accurately quantify the number of mates for each adult subject. Further, his methodology resulted in more offspring being assigned to fathers than mothers, something that is impossible when each child must have both a father and a mother, Gowaty said.

Bateman concluded that male fruit flies produce many more viable offspring when they have multiple mates but that females produce the same number of adult children whether they have one mate or many. But Gowaty and her colleagues, by performing the same experiment, found that the data were decidedly inconclusive.

In their repetition — and possibly in Bateman’s original study — the data failed to match a fundamental assumption of genetic parentage assignments. Specifically, the markers used to identify individual subjects were influencing the parameters being measured (the number of mates and the number of offspring). When offspring die from inherited marker mutations, the results become biased, indicating that the method is unable to reliably address the relationship between the number of mates and the number of offspring, said Gowaty. Nonetheless, Bateman’s figures are featured in numerous biology textbooks, and the paper has been cited in nearly 2,000 other scientific studies.

“Here was a classic paper that has been read by legions of graduate students, any one of whom is competent enough to see this error,” Gowaty said. “Bateman’s results were believed so wholeheartedly that the paper characterized what is and isn’t worth investigating in the biology of female behavior.”

Repeating key studies is a tenet of science, which is why Bateman’s methodology should have been retried as soon as it became important in the 1970s, she said. Those who blindly accept that females are choosy while males are promiscuous might be missing a big piece of the puzzle.

“Our worldviews constrain our imaginations,” Gowaty said. “For some people, Bateman’s result was so comforting that it wasn’t worth challenging. I think people just accepted it.”

Shaking the foundation

Biologists studying sexual selection examine mating habits of organisms ranging from fruit flies to gorillas, both in the lab and in the wild, in order to better understand how certain traits or behaviors confer evolutionary advantages.

Sexual selection began as a discipline following Charles Darwin’s publication of “The Descent of Man, and Selection in Relation to Sex,” considered Darwin’s defense against critics of his theory of evolution through natural selection. He argued that while the unwieldy, colorful tails of peacocks hindered flight and made males easy targets for hungry tigers, the flamboyant plumage served a vital role in attracting potential mates. The overdressed birds had an unexpected evolutionary advantage that did not help when it came to escaping predators but did help when it came to producing offspring through sexual selection, said Gowaty.

Darwin, and later Bateman, cleaved to the notion that females of a species tended to be discriminating and passive while the far more promiscuous males competed for their attention. In the last few decades, however, evolutionary biologists have shown that the story is far more complicated. Gowaty, who has been interested in female mating habits in insects and birds since the beginning of her career, spent 30 years in the field studying Eastern bluebirds. She published the first molecular genetics study showing that females in a socially monogamous species mated outside their traditional pairs regularly.

Gowaty describes the benefits of multiple mates as an answer to the never-ending evolutionary struggle against what may be the world’s greatest predator: disease.

“Our pathogens have much shorter generation times than we do as the hosts, and they evolve offences much more rapidly than we can evolve defences,” she said. “One of the rules of nature is that our pathogens are going to get us.”

In this illness-driven arms race, organisms that produce offspring from multiple mates are more likely to produce some children with the right antibodies to survive the next generation of viruses, bacteria and parasites. Fruit fly males are likely to give females the additional variation in the genome that they need to build strong immune systems in their kids, Gowaty said.

For Gowaty, many open questions are remaining when it comes to female mating habits, whether in fruit flies or other organisms. Yet shaking the bedrock of the Bateman paradigm may help the field examine new perspectives.

“Paradigms are like glue, they constrain what you can see,” she said. “It’s like being stuck in sludge — it’s hard to lift your foot out and take a step in a new direction.”

________

Courtesy University of California – Los Angeles 

This study was federally funded by the National Science Foundation. Other co-authors included Wyatt Anderson, a professor of genetics at the University of Georgia and a member of the National Academy of Sciences, and Yong-Kyu Kim, a research scientist at Emory University.