(Press-News.org) VIDEO: Reverse cannibalism: Some male spiders prefer to eat old females rather than mate with them.
Click here for more information.
The Black Widow spider gets its name from the popular belief that female spiders eat their male suitors after mating. However, a new study has shown that the tendency to consume a potential mate is also true of some types of male spider. The study by Lenka Sentenska and Stano Pekar from Masaryk University in the Czech Republic finds that male spiders of the Micaria sociabilis species are more likely to eat the females than be eaten. The paper, published in Springer's journal Behavioral Ecology and Sociobiology, outlines possible reasons for this behavior.
In nature, female choice of mate is commonly seen as the overriding factor affecting male mating success. Sexual cannibalism is a form of female mate choice with low-quality mates more likely to be cannibalized. However, there is not as much evidence about how males may sometimes dictate the choice of partner. The researchers suggest that in the Micaria sociabilis species, reverse cannibalism seen may be a type of male mate choice.
The researchers collected male and female Micaria sociabilis spiders over a two-year period and studied their behavior by mixing males and females of the species at different time points. All spiders were well fed to discount cannibalism due to hunger. The authors observed what happened when they paired young adult male spiders with single female spiders either from the same generation (young female) or from another generation (old female). By pairing males with females of different size, age and mating status, the researchers hoped to be able to identify whether the reversed form of sexual cannibalism was an adaptive mechanism for male mate choice.
Their study found that cannibalism took place early after the first contact and before any mating took place. The researchers also observed that reverse cannibalism differed significantly, depending on what month it was – most of the incidences were in July. Males from the summer generation tended to be bigger than males from the spring generation and they were more cannibalistic. This would suggest that male aggression may be related to male size.
The authors noted that the highest frequency of reverse cannibalism occurred when these larger, young males from the summer generation met old females from the previous spring generation. This suggests they may have based their choice on female age. Female body size, even though considered to be a sign of quality, did not affect rates of cannibalism. The authors also noted no difference in male cannibalization of females who had previously mated or virgin females. This evidence demonstrates that in some species and some cases, the males make a very clear choice about who they will mate with.
The authors remark: "Our study provides an insight into an unusual mating system, which differs significantly from the general model. Even males may choose their potential partners and apparently, in some cases, they can present their choice as extremely as females do by cannibalizing unpreferred mates."
Reference: Sentenska, L. and Pekar, S. (2013), Mate with young, kill old: reverse sexual cannibalism and male mate choice in the spider Micaria sociabilis (Araneae: Gnaphosidae), Behavioral Ecology and Sociobiology. DOI 10.1007/s00265-013-1538-1
The full-text article, photos and a video-clip are available to journalists on request.
Reversal of the black widow myth
Some male spiders prefer to eat old females rather than mate with them
ELSE PRESS RELEASES FROM THIS DATE:
Possible treatment for serious blood cancer
A single antibody could be the key to treating multiple myeloma, or cancer of the blood, currently without cure or long-term treatment. "We tested the antibody in various ways, including on tumour cells from myeloma patients that have been transplanted into mice. The tests showed that the antibody is able to destroy myeloma cells", explains Markus Hansson, a researcher at Lund University in Sweden. Using a 'biological library' of thousands of antibodies from the company BioInvent in Lund, the team singled out antibody BI-505, shown to have a powerful effect on the ...
Researchers reveal new more precise method of performing electroconvulsive therapy
Philadelphia, PA, May 6, 2013 - Electroconvulsive therapy (ECT) is the most effective acute treatment for severe major depression. However, even with newer forms of ECT, there remains a significant risk of adverse cognitive effects, particularly memory problems. Current theories hold that the regions that need to be stimulated to treat the depression (the cortex) are different and separate from the regions that result in memory problems (the hippocampus and temporal lobes). Theoretically, a more precise form of ECT could have all of the efficacy and few or none of the ...
Columbia engineers manipulate a buckyball by inserting a single water molecule
New York, NY—May 3, 2013—Columbia Engineering researchers have developed a technique to isolate a single water molecule inside a buckyball, or C60, and to drive motion of the so-called "big" nonpolar ball through the encapsulated "small" polar H2O molecule, a controlling transport mechanism in a nanochannel under an external electric field. They expect this method will lead to an array of new applications, including effective ways to control drug delivery and to assemble C60-based functional 3D structures at the nanoscale level, as well as expanding our understanding of ...
The nocebo effect: Media reports may trigger symptoms of a disease
Media reports about substances that are supposedly hazardous to health may cause suggestible people to develop symptoms of a disease even though there is no objective reason for doing so. This is the conclusion of a study of the phenomenon known as electromagnetic hypersensitivity. Those affected report experiencing certain symptoms on exposure to electromagnetic waves, such as those emitted by cell phones, and these take the form of physical reactions. With the help of magnetic resonance imaging, it has been demonstrated that the regions of the brain responsible for pain ...
Do-it-yourself invisibility with 3-D printing
DURHAM, N.C. – Seven years ago, Duke University engineers demonstrated the first working invisibility cloak in complex laboratory experiments. Now it appears creating a simple cloak has become a lot simpler. "I would argue that essentially anyone who can spend a couple thousand dollars on a non-industry grade 3-D printer can literally make a plastic cloak overnight," said Yaroslav Urzhumov, assistant research professor in electrical and computer engineering at Duke's Pratt School of Engineering. Three-dimensional printing, technically known as stereolithographic fabrication, ...
A KAIST research team developed in vivo flexible large scale integrated circuits
Daejeon, Republic of Korea, May 6th, 2013–-A team led by Professor Keon Jae Lee from the Department of Materials Science and Engineering at KAIST has developed in vivo silicon-based flexible large scale integrated circuits (LSI) for bio-medical wireless communication. Silicon-based semiconductors have played significant roles in signal processing, nerve stimulation, memory storage, and wireless communication in implantable electronics. However, the rigid and bulky LSI chips have limited uses in in vivo devices due to incongruent contact with the curvilinear surfaces of ...
Occupational data in medical billing records could prevent workplace injuries
PHILADELPHIA (May 6, 2013)— A subtle change to hospital data collection policies could make a big difference in preventing occupational health and safety hazards, according to workplace safety researchers at the Drexel University School of Public Health. In a new article published in the Journal of Occupational and Environmental Medicine, the researchers call on industry, occupational medicine and public health communities to support a change to data collection methods to include industry and occupation data. Every year, nearly four million Americans suffer a workplace ...
More than a good eye: Carnegie Mellon robot uses arms, location and more to discover objects
PITTSBURGH—A robot can struggle to discover objects in its surroundings when it relies on computer vision alone. But by taking advantage of all of the information available to it — an object's location, size, shape and even whether it can be lifted — a robot can continually discover and refine its understanding of objects, say researchers at Carnegie Mellon University's Robotics Institute. The Lifelong Robotic Object Discovery (LROD) process developed by the research team enabled a two-armed, mobile robot to use color video, a Kinect depth camera and non-visual information ...
Commands from the matrix
Environment moulds behaviour - and not just that of people in society, but also at the microscopic level. This is because, for their function, neurons are dependent on the cell environment, the so-termed extracellular matrix. Researchers at the Ruhr-Universität have found evidence that this complex network of molecules controls the formation and activity of the neuronal connections. The team led by Dr. Maren Geißler und Prof. Andreas Faissner from the Department of Cell Morphology and Molecular Neurobiology reports in the "Journal of Neuroscience" in collaboration with ...
Weight gain linked with personality trait changes
People who gain weight are more likely to give in to temptations but also are more thoughtful about their actions, according to a new study published in Psychological Science, a journal of the Association for Psychological Science. To understand how fluctuations in body weight might relate to personality changes, psychological scientist Angelina Sutin of the Florida State University College of Medicine and colleagues at the National Institutes of Health (NIH) examined data from two large-scale longitudinal studies of Baltimore residents. "We know a great deal about ...
LAST 30 PRESS RELEASES:
Ghent University’s research team envisions a bright future with active machine learning in chemical engineering
Climate change and carnivores: shifts in the distribution and effectiveness of protected areas in the Amazon
Can ChatGPT help us form personal narratives?
An intelligent control method reduces carbon emissions in energy-intensive equipment
Groundbreaking control method reduces carbon emissions from zinc oxide rotary kilns, boosting profits for zinc smelting industry
Small but mighty new gene editor
Study finds SARS-CoV-2-associated sepsis was more common, deadly than previously thought
Use of electronic clinical data to track incidence and mortality for SARS-CoV-2–associated sepsis
Misinformation, trust, and use of ivermectin and hydroxychloroquine for COVID-19
Neighborhood factors, individual stressors, and cardiovascular health among Black and white adults
New research reveals link between childhood mental health problems and quality of life for young adults
New insights into how the human brain organises language
Visual search: Context facilitates more effective strategies
Malaria: Treatment of Plasmodium falciparum malaria patients under threat in the Horn of Africa
New post-translational modification of the glycolytic enzyme enolase
New frontier in biomedical engineering: Protein coacervates engineered into adhesive for unprecedented skin repair speed
New study unveils insights into ethylene copolymerization with linear and end-cyclized olefins using a metallocene catalyst
Study identifies new pathway to suppressing autoimmunity
Diabetes may accelerate blood cancer growth, yet survival outcomes differ by race
Groundbreaking mathematical proof: new insights into typhoon dynamics unveiled
Teams invent a new metallization method of modified tannic acid photoresist patterning
MoMFs could be central to liver regeneration
A lethal parasite’s secret weapon: Infecting non-immune cells
Ball milling provides high pressure benefits to battery materials
Congenital Heart Surgeons' Society (CHSS) and fourteen professional organizations announce recommendations for performing pediatric heart surgery in US
Mouthwash for dogs: water additive with pomegranate helps to keep canine teeth healthy
Racial/ethnic minority patients may be less likely than white patients to receive palliative care during breast cancer treatment
Spanish-speaking men in sexual minority groups may lack knowledge about cancers linked to HPV
Structural racism may play a role in increased cancer mortality rates among racial minorities
Racial and ethnic minorities may be less willing than others to participate in clinical trials[Press-News.org] Reversal of the black widow myth
Some male spiders prefer to eat old females rather than mate with them