Orb web spiders found to be better guards after sex

first_img More information: Emasculation: gloves-off strategy enhances eunuch spider endurance, Biology Letters, Published online before print June 13, 2012, doi: 10.1098/rsbl.2012.0285AbstractMales of sexually cannibalistic spiders commonly mutilate parts of their paired genitals (palps) during copulation, which may result in complete emasculation or the ‘eunuch phenomenon’. In an orb-web nephilid spider, Nephilengys malabarensis, about 75 per cent of males fall victim to sexual cannibalism, and the surviving males become half-eunuchs (one palp emasculated) or full-eunuchs (both palps emasculated). While it has been shown that surviving eunuchs are better fighters compared with intact males when guarding the females with which they have mated, mechanisms behind eunuchs’ superior fighting abilities are unknown. The previously proposed ‘gloves-off’ hypothesis, attributing eunuchs’ enhanced locomotor endurance to the reduction in total body weight caused by genital mutilation, is plausible but has remained untested. Here, we tested the gloves-off hypothesis in N. malabarensis by comparing the time until exhaustion (i.e. endurance) of intact males with half- and full-eunuchs created experimentally. We found that by reducing body weight up to 4 per cent in half-eunuchs and 9 per cent in full-eunuchs through emasculation, endurance increases significantly in half-eunuchs (32%) and particularly strongly in full-eunuchs (80%). Our results corroborate the gloves-off hypothesis and further point towards the adaptive significance of male emasculation. Previously, Daiqin Li and colleagues at the National University of Singapore found that the male orb web spider loses its sex organ, called a palp, due to it breaking off during sex because it allowed the male to continue pumping in sperm even as the male was either eaten by the female or fled the scene. Now new research by the same team has found that for those males that escape the female after mating, the loss of the heavy palp affords the survivors more stamina in warding off other would be suitors, thus helping to ensure that the original male produces offspring. The team has published a paper on their findings in the journal Biology Letters. Sex for male orb web spiders is truly a risky business. The researchers found that only about twenty five percent of them survive the encounter as the females are bigger and stronger and eat the males whenever they get the chance. Because of this, the researchers say, the male has evolved to where it allows its palp to break off during the tryst so that he might better escape being eaten, while still finishing the job he set out to do, namely, copulate to produce progeny. After he’s dead or gone, his palp continues to push his sperm into the female, thus increasing his chances of producing offspring. But the researchers have now found that those that do survive make much better guards than they would were their palps still attached due to increased stamina. This is because the palps are pretty big and heavy compared to the rest of the spider’s anatomy.To find out just how much more stamina the spiders have without their palps, the researchers removed them manually from several volunteers and then subjected them to endurance testing. In so doing, they found that spiders with one palp removed (which reduced its body weight by four percent) had 32% more endurance than did spiders that retained both. Even more remarkably, when both palps were removed, reducing its body weight by nine percent, the spiders showed an increase in endurance of up to 80%.This is important for the spiders because once they’ve mated, their sole reason for living is warding off other suitors seeking to replace the original mater’s sperm with some of their own. With their lowered weight, those spiders that have already mated not only have more endurance but are lighter on their feet so to speak, giving them a huge advantage over other males still carrying around their cumbersome palps. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Journal information: Biology Letters Citation: Orb web spiders found to be better guards after sex (2012, June 14) retrieved 18 August 2019 from https://phys.org/news/2012-06-orb-web-spiders-sex.htmlcenter_img © 2012 Phys.Org Nephilengys malabarensis. Image (c) Daiqin Li/University of Singapore Explore further Male spiders of one species lose their genitals after sex to increase sperm count in femaleslast_img read more

Researchers find evidence of speedy core formation in solar system planetesimals

first_img New study finds ‘geologic clock’ that helps determine Moon’s age (Phys.org) —A combined team of researchers from Germany, Switzerland and the U.S. has found evidence of faster than thought core formation of planetesimals in our solar system. In their paper published in the journal Science, the team describes how they came up with a new approach to using tungsten isotope dating in a way that overcame the problem of cosmic rays affecting accuracy. Tim Elliot offers a Perspective piece in the same issue delving further into the work by the team and explains how the new findings are likely to lead to better dating for planetary development in general. Citation: Researchers find evidence of speedy core formation in solar system planetesimals (2014, June 6) retrieved 18 August 2019 from https://phys.org/news/2014-06-evidence-speedy-core-formation-solar.html Journal information: Science © 2014 Phys.org Planetary core formation. Credit: Speed metal, Science 6 June 2014.center_img Scientists believe approximately 4.6 billion years ago, our solar system was little more than a star surrounded by a molecular cloud. That cloud eventually coalesced into a proto-planetary disk which eventually coalesced further into planetesimals. Planets and moons and other bodies in the solar system came about as a result. But, one thing that has puzzled space scientists was the rate at which the cores of the planetesimals formed, or put another way, how soon after the formation of solar system, did the cores start to form? To come up with a good approximation, the researchers looked to existing iron meteorites—they are believed to been the creative force behind core formation.To determine the age of five existing iron meteorites, the researchers used tungsten radioactive isotope dating, an approach used before. Such prior efforts were hobbled in their accuracy, however, by the impact of cosmic rays over time. To get around that problem, the researchers used platinum isotope compositions. Doing so allowed the researchers to calculate that core formation of early planetesimals likely began as early as 100,000 years to 300,000 years after the formation of the solar system.These findings help explain why the materials that made up the bodies currently in our solar system weren’t blown away by the sun—previous estimates suggested core formation took up to twenty million years, enough time to push such materials beyond our stars’ gravitational pull. With such a short formation time, however, the cores of the developing planetesimals would have formed before they were pushed too far out, allowing them to be captured by the tug of the sun’s gravity. More information: Protracted core formation and rapid accretion of protoplanets, Science 6 June 2014: Vol. 344 no. 6188 pp. 1150-1154 DOI: 10.1126/science.1251766ABSTRACTUnderstanding core formation in meteorite parent bodies is critical for constraining the fundamental processes of protoplanet accretion and differentiation within the solar protoplanetary disk. We report variations of 5 to 20 parts per million in 182W, resulting from the decay of now-extinct 182Hf, among five magmatic iron meteorite groups. These 182W variations indicate that core formation occurred over an interval of ~1 million years and may have involved an early segregation of Fe-FeS and a later segregation of Fe melts. Despite this protracted interval of core formation, the iron meteorite parent bodies probably accreted concurrently ~0.1 to 0.3 million years after the formation of Ca-Al–rich inclusions. Variations in volatile contents among these bodies, therefore, did not result from accretion at different times from an incompletely condensed solar nebula but must reflect local processes within the nebula. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore furtherlast_img read more

Research efforts yielding major advances in understanding immunological memory

first_img(Phys.org)—Two teams of researchers both working in the U.S. have announced new breakthroughs in better understanding how immunological memory works. Both teams have published their findings in the journal Nature. The first team, made up of members from several academic institutions across the country, describe their study of part of the process by which bacteria fend off secondary viral attacks. The second team, with Rockefeller University, describes a system they devised for in vitro study of immunological memory at the bacterial level. Ido Yosef and Udi Qimron with Tel Aviv University offer a News and Views piece on the work done by the two teams in the same journal issue. Escherichia coli. Credit: Rocky Mountain Laboratories, NIAID, NIH More information: Paper 1: Integrase-mediated spacer acquisition during CRISPR–Cas adaptive immunity, Nature (2015) DOI: 10.1038/nature14237Paper 2: Cas9 specifies functional viral targets during CRISPR–Cas adaptation, Nature (2015) DOI: 10.1038/nature14245News and Views: Microbiology: How bacteria get spacers from invaders, Nature (2015) DOI: 10.1038/nature14204 Bacterial immune system has a better memory than expected Explore further Citation: Research efforts yielding major advances in understanding immunological memory (2015, February 19) retrieved 18 August 2019 from https://phys.org/news/2015-02-efforts-yielding-major-advances-immunological.htmlcenter_img In humans and many other animals, part of the work of immunity involves storing information about previous viral or bacterial attacks so those of the same type can be more easily thwarted in the future. Until very recently, scientists believed this “memory” type of immunity was unique to vertebrates. Over the past few years, researchers have found this assumption to be false—they have found, as one example, that bacteria too have immunological memory that helps them fight off viral infections.To remember viral infections, bacteria grab short snippets of its DNA during an attack—the snippets are called protospacers and make their way into bacterium DNA. Once entrenched they are called clustered regularly interspaced short pallindronic repeats (CRISPRs)—as a group they are referred to as spacers. The researchers with the first effort sought to uncover how it is that spacers are “chosen” by an individual bacterium in such a way as to prevent damage to its own sequences as pieces are cleaved to allow for retention. They found that a protein called Cas9 drives the selection process.To learn more about how the immune system works, in all species, studies are done both in vitro and in vivo. Most work done to date at the bacterial level has been conducted in vivo. The team at RU has developed a system whereby future research using an in vitro approach can be used—it is based on E. coli memorizing proteins.Learning more about how the immune system works in simple organisms allows researchers to uncover some of the basic properties involved, which hopefully can be applicable to those in larger organisms, such as human beings. Journal information: Nature This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. © 2015 Phys.orglast_img read more

Four new shortperiod giant planets discovered

first_imgUnbinned transit light curves for HATS-43. Credit: Brahm et al., 2017. HATSouth is a network of six astrograph telescope systems located in South America, Africa, and Australia. These telescopes are designed to detect transiting extrasolar planets in orbit around relatively bright stars visible from the Southern hemisphere. Since its launch in 2009, the network has already detected dozens of transiting exoplanets.Now, the list of planets detected by HATSouth has expanded. In a recent paper, a team of researchers led by Rafael Brahm of the Pontifical Catholic University of Chile in Santiago presents the discovery of four new planets, HATS-43b, HATS-44b, HATS-45b, and HATS-46b. The planetary nature of transiting signals detected by HATSouth was confirmed by follow-up spectroscopic and photometric observations using various instruments, including the Las Cumbres Observatory Global Telescope (LCOGT) network at the Cerro Tololo International Observatory (CTIO) in Chile.This extensive observational campaign that led to the discovery of four new alien worlds was carried out from December 2009 to October 2016.”We have presented the discovery of four new short-period transiting systems from the HATSouth network. The systems were identified as planetary candidates using HATSouth photometric light curves and then confirmed as planetary mass objects by measuring precise radial velocities for the host stars,” the astronomers wrote in the paper.According to the paper, HATS-45b is the largest and most massive exoworld of all the newly discovered exoplanets. It has a radius of about 1.29 Jupiter radii and is 30 percent less massive than our solar system’s biggest planet. It orbits its parent star every 4.19 days.HATS-46b has the longest orbital period and is the least massive of the newly found quartet. It has only 17 percent of the mass of Jupiter, however a radius of approximately 0.9 Jupiter radii. It takes this planet 4.74 days to fully circle its host.HATS-43b and HATS-44b are similar in radius—1.18 and 1.07 Jupiter radii respectively. HATS-43b has a mass of 0.26 Jupiter masses, while HATS-44b is about two times more massive—0.56 Jupiter masses. The shortest orbital period among the four newly identified planets belongs to HATS-44b, which orbits its star in just 2.74 days. When it comes to HATS-43b, it takes it approximately 4.39 days to circle its parent star.In general, the newly found planets have orbital periods shorter than five days and masses in the Neptune to Jupiter mass range, however all of them have radii similar to that of Jupiter.The researchers concluded that their finding is an important addition to the still-growing collection of planetary systems with determined basic parameters.”These four new systems add to the valuable population of extrasolar planets transiting stars with precisely determined masses and radii,” the paper reads. Citation: Four new short-period giant planets discovered (2017, July 26) retrieved 18 August 2019 from https://phys.org/news/2017-07-short-period-giant-planets.html Explore further New ‘hot Jupiter’ with short orbital period discovered More information: HATS-43b, HATS-44b, HATS-45b, and HATS-46b: Four Short Period Transiting Giant Planets in the Neptune-Jupiter Mass Range, arXiv:1707.07093 [astro-ph.EP] arxiv.org/abs/1707.07093AbstractWe report the discovery of four short period extrasolar planets transiting moderately bright stars from photometric measurements of the HATSouth network coupled to additional spectroscopic and photometric follow-up observations. While the planet masses range from 0.26 to 0.90 MJ, the radii are all approximately a Jupiter radii, resulting in a wide range of bulk densities. The orbital period of the planets range from 2.7d to 4.7d, with HATS-43b having an orbit that appears to be marginally non-circular (e= 0.173±0.089). HATS-44 is notable for a high metallicity ([Fe/H]= 0.320±0.071). The host stars spectral types range from late F to early K, and all of them are moderately bright (13.3 © 2017 Phys.org (Phys.org)—Astronomers have detected four new giant exoplanets as part of the Hungarian-made Automated Telescope Network-South (HATSouth) exoplanet survey. The newly found alien worlds are about the size of Jupiter, but less massive. They transit moderately bright stars and have short orbital periods. The findings were presented July 22 in a paper published on arXiv.org. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Reviving Indian craft and culture

first_imgThe fair showcases the richness and diversity of the handicrafts, handlooms and the cultural heritage of India. The aim of this event is to recreate a pristine rural ambience for foreign and domestic tourists, tell the patrons of arts and crafts of the skills involved in creative arts, to introduce craft persons directly to the buyers, and to identify, nurture and preserve the languishing crafts of the country.  Chhattisgarh is theme state this year. It will showcase its tribal heritage and culture, which is still found well-preserved in the forests of Bastar. The skilled craft persons, talented artistes and master chefs from the state will participate in the mela. Also, an ethnic ambience representing the state’s rural ethos is created on the mela grounds. 18 countries are expected to participate in this fair.  Lebanon, the partner nation of the mela this year, will unveil its ancient heritage of creating crafts in style. Lebanon will showcase to the world their identity as a nation, its history, culture, arts, cuisine, customs and traditions; and leave an everlasting memory in the hearts and minds of the people of India who come to Surajkund. To enliven the visitors’ mood, scintillating performances will be presented by international folk artistes from Lebanon, Sri Lanka, Armenia, Azerbaijan, Russia  Also Read – ‘Playing Jojo was emotionally exhausting’Federation (Moscow), Belarus, Kyrgyzstan, Kazakhstan, Uzbekistan, Georgia and Tajikistan.Vivanta by Taj, Surajkund is also celebrating the event by recreating the highlights of the fair within the property. It features varied activities that would capture the interest of guests across age groups. From wine-tasting and themed evenings to special kids’ activities and menu, there is something for everyone.Also, Pawan Hans is commencing Helicopter Joy Ride during the mela to take visitors on a joy ride flight by Pawan Hans Helicopter and experience the breathtaking beauty through aerial view of Surajkund Mela and surrounding areas.  The rate of per ticket is Rs. 2,000/- which can be booked on the spot.last_img read more

Network18 slips to sharp Rs 27cr quarterly loss

first_imgNetwork18 Media and Investments on Wednesday reported a consolidated net loss of Rs 27.42 crore for the second quarter ended September 30. The company had registered a consolidated net loss of Rs 36.46 crore in the same period a year ago. Network18’s total income from operations for this quarter stood at Rs 795.1 crore. It was Rs 736.12 crore during the same period of the previous fiscal.last_img

Villagers clash after morphed images go viral 25 injured

first_imgBardhaman(WB): Twenty-five people have been injured in a clash between villagers of Purba Goalpara and Dangapur over morphed pictures of local women doing the rounds on social media, a police officer said today. Twenty-nine people have been arrested till now in connection with the incident that took place yesterday and raids are on in the two villages, Additional Superintendent of Police(Rural), East Bardhaman, Raj Narayan Mukherjee said. The residents of Dangapur village suspected the involvement of Sheikh Rakibul of neighbouring Purba Goalpara village in uploading the morphed pictures of the women on social networking sites on Tuesday. Also Read – Rain batters Kolkata, cripples normal life Sheikh Rakibul’s brother Sheikh Hijbullah claimed that the matter had been sorted out at a meeting held in Madanghat Police Station on Tuesday. The police, however, said no such meeting had been held at the police station. Yesterday, some people supporting Sheikh Rakibul clashed with villagers at Dangapur and both the groups attacked each other with rods, stones and sharp weapons, a local police officer said. He said 16 of the injured were admitted to the Kalna sub-divisional hospital and the rest were taken to nearby hospitals.last_img read more

Body of driver found inside truck

first_imgKOLKATA: A truck driver’s dead body was found inside an abandoned truck at Chanditala in Hooghly. The driver was later identified as Keshto Bhagat. His throat was slit using some sharp weapon.According to police sources, the truck was coming from Durgapur loaded with iron materials. The owner of the truck lost contact with Bhagat after 9 pm on Sunday. Despite repeated efforts, Bhagat could not be reached as his phone was found to be switched off. Having no other way, the owner tried to locate the truck as well but failed. On Monday late night, some locals from Panchghora at Chanditala noticed a truck was standing for quite a long time on the Kolkata bound flank of Durgapur Expressway. Being curious some locals went to investigate and after getting near, one noticed blood on the truck. Immediately, Chanditala Police Station was informed. Police later recovered Bhagat’s body from the driver’s cabin. A murder case has been initiated by the police. The sleuths are suspecting that Bhagat might have been killed by some miscreants over robbery. Police are checking the whereabouts of local miscreants. Till Tuesday night no one was arrested.last_img read more

Reap the benefits of pudina

first_imgPudina (mint leaves) aids in digestion, improves oral health, treats cold and more, say experts.Mint leaves are loaded with anti-oxidants and phytonutrients which provide relief to the stomach muscles and help in digestion. It soothes the stomach instantly and works wonders when it comes to treating tummy troubles. For example, pudina chutney that is served with samosa is not only just to enhance our taste buds but for better digestion of the junk food. The herb is a naturally soothing substance, so it can alleviate the inflammation and temperature rise that is often associated with headaches and migraines.Improving the health of a person’s mouth is a well-known benefit of mint. Since it has germicidal qualities and quickly freshens breath, it adds to oral health by inhibiting harmful bacterial growth inside the mouth and by cleaning the tongue and teeth.The anti-inflammatory and anti-bacterial properties work wonders for acne-prone skin. Also, when applied topically, mint has the effect of calming and cooling the skin affected by insect bites, a rash or other reactions.Pudina is one of those herbs which not only has general benefits but also has therapeutic values. If people have any kind of digestion problem like gas formation, indigestion, vomiting and diarrhoea, pudina can be used effectively in different formats.last_img read more

Student falls off window dies

first_imgDarjeeling: A Class-IX student of Narayana School in Jatiakhali, Siliguri, fell from the second floor out of an open window and died. Another student, who also fell off the window, is admitted to a private hospital with injuries.Prima facie the two boys pushed each other while playing and they fell off the sliding windows on Monday. The deceased Rishab Arya was from Purnia, Bihar. “The grill of the classroom had loosened and had been removed for replacement. The workman was not present as had gone to his sister’s wedding,” said Santosh Kumar Yadav, deputy general manager of the school. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataThe school remained closed on Tuesday and will remain closed on Wednesday also for maintainance work stated Yadav. The body of the deceased student was handed over to his father on Thursday. “We have nothing to say. Rishab had plans to go for higher studies to Delhi. Everything has ended,” stated Arun Kumar, his father. The other student Ritwick Kumar Singh is a day scholar. He suffered multiple fractures. These two students were near the window which had the open slide. They were rushed to a private nursing home. “We feel that there has been a sheer lapse on the part of the authorities. How can a student fall out of a window during school hours? They should have a safety and security monitoring system in place,” stated Sandipan Bhattacharya, president, Guardian’s Forum of North Bengal.last_img read more