Aggression in male chimpanzees leads to mating success

November 13, 2014

In the animal kingdom, the battle of the sexes often truly becomes a battle. Among chimpanzees, males may violently attack females, sometimes resulting in serious wounds. While unpleasant to watch, the frequent occurrence of such violence at several East African field sites suggests that aggression toward females functions as a form of sexual coercion.

Previous research from the Kanyawara chimpanzee community in Kibale National Park, Uganda, has supported the sexual coercion hypothesis. Males who directed aggression at certain females mated more often with those females than did other males. Moreover, these aggressive males were actively solicited for mating by those females at the time of peak fertility. Critically, aggression over the long term had a greater effect than violence in the immediate context of mating. Ian Gilby in the field Download Full Image

However, until now, it has been unclear whether aggression toward females increases male chimpanzee reproductive success.

A new study published this week in Current Biology by Feldblum et al., including ASU scientist Ian Gilby, a senior author on the study, provides strong evidence that male aggression toward females is indeed adaptive. The authors analyzed 17 years of observations of the Kasekela chimpanzee community in Gombe National Park, Tanzania.

Researchers used DNA obtained from fecal material to determine the paternity of 31 infants born during the study period. This is the first study to present genetic evidence of long-term sexual coercion as an adaptive strategy in a social mammal.

The rate at which a male directed aggression at a female not only increased the pair’s mating frequency, but also significantly increased the probability that he sired her offspring. This strategy was most effective for high-ranking males, and aggression toward females outside of their periods of sexual receptivity was the best predictor of paternity. Male aggression was not used to force sexual encounters either during or immediately following aggression.

“This indicates that males, particularly those of high rank, successfully employ a strategy of long-term sexual intimidation,” says Ian Gilby, an assistant professor in the School of Human Evolution and Social Change and research affiliate with the Institute of Human Origins at Arizona State University.

Although there could be female preference for dominant males, the fact that aggression increased paternity likelihood for high-ranking males indicates that the patterns of paternity did not arise as a result of female choice but rather from mate guarding by strong alpha males.

Gilby cautions that while these results may provide clues about the origins of sexual violence in humans, he says, “We should be careful not to jump to conclusions. Chimpanzees are one of our closest living relatives, but 7 million years of evolution separate us, and our mating systems are very different. Nevertheless, recognizing the adaptive value of male-female aggression in chimpanzees may ultimately help us to understand, and hopefully prevent, similar behavior among humans.”

Julie Russ

Assistant director, Institute of Human Origins


ASU-Mayo seed grants advance new research in cancer, obesity

November 13, 2014

Each year, the ASU-Mayo Seed Grant Program funds promising new research projects aimed at improving human health. This year, 10 teams have been selected for the 2015 program to advance research in critical areas that include cancer, bioinformatics, neuroscience technology, detection and imaging, health care delivery, and metabolic disease and obesity

The seed grant program, which has funded 64 projects since it was established in 2004, is yet another aspect of the ASU-Mayo Clinic relationship, with its long history of successful collaborations in health care, medical research and education. The partnership includes joint faculty appointments, degree programs and research projects, and the ASU Department of Biomedical Informatics, which is located at the Mayo Clinic Scottsdale campus. doctor examining x-ray Download Full Image

“The program is directed at forming cross-institutional collaborations between researchers whose expertise is complementary. They develop vigorous research projects combining basic biomedical and behavior research with clinical research,” says William Petuskey, associate vice president of science, engineering and technology for Knowledge Enterprise Development at ASU and an administrator of the seed grant program. “The synergies that have evolved from these initial connections have resulted in much larger research programs that have translated to tangible and valuable benefits to patients.”

Creating funding opportunities

Seed grants launch promising new research projects and bring them to the point where they can attract more substantial funding from external sources. For example, Ariel Anbar, President’s Professor from ASU’s School of Earth and Space Exploration, and Rafael Fonseca from Mayo Clinic received a seed grant in 2012 to study calcium isotopes as indicators of the progress of multiple myeloma, a type of cancer. Since then, the team has received $1.2 million in additional funding from organizations including NASA, Flinn Foundation and Arizona Science Foundation.

“The ASU-Mayo Seed Grant Program enabled us to generate pilot data showing that our geochemical technique could provide insight into a disease,” says Anbar. “This allowed us to secure a new round of funding from NASA’s human research program, generate the data for a recent paper in (the journal) Leukemia, and positions us well to pursue funding from the National Institutes of Health."

Due to a significant increase in applicants over last year, the program doubled the number of awards given, from five in 2014 to 10 in 2015. Next year, the program will raise the total potential award to $50,000 for eight winning teams.

"The seed grant program has served as a platform for innovative, medically relevant scientific research for over a decade,” says Dean Wingerchuk, professor of neurology and vice chair for clinical research at Mayo Clinic in Arizona. “It continues to facilitate productive investigative teamwork between Mayo Clinic and ASU, resulting in substantial growth of programs in areas of mutual interest and priority.”

2015 projects

• “Electrocorticographic recordings from human cortex for mapping cortical information processing and decoding dextrous hand movements.” Bradley Greger, associate professor, ASU School of Biological and Health Systems Engineering; Joseph Drazkowski, professor of neurology, Mayo Clinic.

• “Continuous blood lactate monitoring in critically ill patients.” Jeffrey LaBelle, assistant professor, ASU School of Biological and Health Systems Engineering; Ayan Sen, assistant professor of emergency medicine, Mayo Clinic.

• “Robust intensity-modulated proton therapy.” Jianming Liang, associate professor, ASU Department of Biomedical Informatics; Wei Liu, assistant professor of radiation oncology, Mayo Clinic.

• “Single cell analysis of breast cancer tumor heterogeneity.” Karen Anderson, associate professor, ASU Biodesign Institute; Michael Barrett, associate professor of neurology, Mayo Clinic.

• “Magnetic resonance imaging texture analysis for the discrimination of human papilloma virus related oropharyngeal cancer.” Jing Li, associate professor, ASU School of Computing, Informatics and Decision Systems Engineering; Joseph Hoxworth, assistant professor of radiology, Mayo Clinic.

• “New emotion-focused interventions for smoking prevention and cessation.” Michelle Shiota, associate professor, ASU Department of Psychology; Scott Leischow, professor of health services research, Mayo Clinic.

• “A new dimension in modeling irritable bowel syndrome (IBS) to elucidate novel diagnostic biomarkers and microbiome signatures.” Cheryl Nickerson, professor, ASU Biodesign Institute; Amy Foxx-Orenstein, professor of medicine, Mayo Clinic.

• “Development of an in vivo canine larynx with full neuromuscular control.” Juergen Neubauer, associate research professor, ASU School of Human Evolution and Social Change; David Lott, assistant professor of otolaryngology, Mayo Clinic.

• “Multivariable models of brain structure that classify post-traumatic headache and differentiate it from migraine.” Visar Berisha, assistant professor, ASU College of Health Solutions; Todd Schwedt, associate professor of neurology, Mayo Clinic.

• “Anticipatory analytics for post-cardiac surgery cognitive impairment.” Daniel Bliss, associate professor, ASU School of Electrical, Computer and Energy Engineering; Amy Crepeau, assistant professor of neurology, Mayo Clinic.

Learn more about past seed grant recipients. If you are an ASU researcher, sign up to receive notifications about funding.

Written by Kelsey Wharton, Office of Knowledge Enterprise Development.

Kelsey Wharton

Science Writer, Knowledge Enterprise Development