(Press-News.org) Like gangsters running a protection racket, drongos in the Kalahari Desert act as lookouts for other birds in order to steal a cut of their food catch. The behaviour, revealed in research funded by the Biotechnology and Biological Sciences Research Council (BBSRC) published in Evolution and reported in Nature's Research Highlights today (18 November), may represent a rare example of two species evolving from a parasitic to a mutualistic relationship.
The team from the Universities of Bristol, Cambridge and Cape Town showed that victimised pied babblers gained a mitigating benefit from the presence of thieving drongos because, by keeping watch for predators, the drongos allowed the babblers to focus on foraging and so catch more insects.
Many apparently harmful parasites seem to be tolerated by their hosts and the provision of compensatory benefits to victims could underpin a range of host-parasite relationships. The insight the research provides into complex co-evolution between species gives scientists a valuable way of understanding other important relationships, such as those between drugs and bacteria and between pathogens and hosts.
Dr Andrew Radford, who led the research funded through a BBSRC David Phillips Fellowship, said: "Because drongos are parasitic birds who swoop in to steal food from other species, you'd expect them to keep a low profile while waiting. Rather surprisingly, however, drongos perched above foraging babblers advertise their presence by issuing a call called a 'twank' every 4 or 5 seconds.
"When we played back these 'twank' calls to a babbler group, we found that they spread out over a larger area and lifted their heads less often, indicating that they were less fearful of predators when they thought a drongo was keeping watch. We think that drongos have evolved to alert babblers to their presence because helping the group forage more effectively leads to more frequent opportunities for theft."
Drongos have an ingenious way of catching food: by crying wolf about the presence of predators, they scare other animals into dropping their catch, which the birds then pounce on. This research indicates that pied babblers have evolved to tolerate the drongos giving false warnings and stealing some of their hard-earned gains in exchange for the chance to forage in relative safety when a drongo is keeping watch.
Dr Radford continued: "Like any good gangster, as well as lying and stealing, the drongos also provide protection by mobbing aerial predators and giving true alarm calls on some occasions. But, despite all of the useful services drongos provide, the foraging birds are still more responsive to calls from other babblers. It seems likely that the babblers simply don't trust the drongo mafia as much as their own flesh and blood."
Professor Douglas Kell, BBSRC Chief Executive said: "Evolutionary arms-races, including those between parasites and their hosts, and plants and animals and the diseases that they suffer, underlie a whole range of socially and economically important areas of biology. From drug and pesticide resistance to the biodiversity of ecosystems, deepening our understanding how a range of organisms have evolved into complex relationships will help us address important social issues in a smarter, more holistic way."
INFORMATION:
The research was carried out with the support of the Percy FitzPatrick Institute of African Ornithology at the University of Cape Town, Magdalene College, Cambridge, and the EU.
END
Different techniques should be used to remove single stones that have become lodged in the distal ureter after being expelled by the kidney, depending on whether they are under or above one centimetre, according to the December issue of BJUI.
Surgeons from the Department of Urology at University Federico II, Naples, Italy, believe that extracorporeal shockwave lithotripsy (ESWL) - which uses a non-invasive acoustic pulse to break down ureteric stones - should be the treatment of first choice in patients with a stone of up to 1cm. Patients with a stone over 1cm should ...
The video games industry is leading the overall trend of transformation of digital products into e-services, according to the report "Born digital/ Grown digital – Assessing the future competitiveness of the EU video games software industry" published today by the European Commission's Joint Research Centre. Online games, for example, play a major role in the digital content convergence process based on digital distribution of different types of content and the diffusion of interactive capabilities for consumers. This phenomenon is having an effect on the movie, video, ...
Scientists and engineers at the internationally acclaimed Space Research Centre at the University of Leicester are developing a conceptual motor design for a Mars 'hopping' vehicle which should lead to a greater understanding of the 'Red Planet'.
Their research findings have been published this month by the Proceedings of the Royal Society A (http://rspa.royalsocietypublishing.org/content/early/2010/11/11/rspa.2010.0438.short?rss=1 )
Robots exploring Mars can carry scientific instruments that measure the physical and chemical characteristics of the Martian surface ...
Researchers funded by the BBSRC Crop Science Initiative have made a discovery that could instigate a paradigm shift in breeding resistance to late blight – a devastating disease of potatoes and tomatoes costing the industry £5-6 billion a year worldwide. They will share this research with industry at an event in London later today (18 November).
Professor Paul Birch of the University of Dundee and his team at the Scottish Crop Research Institute (SCRI), the University of Dundee, and the University of Aberdeen have developed a new approach to breeding resistance to the ...
Researchers have uncovered the genetic basis of remarkable broad-spectrum resistance to a viral infection that, in some parts of the world, is the most important pathogen affecting leafy and arable brassica crops including broccoli, cauliflower, cabbage, kale, swede and oilseed rape. They have tested resistant plants against a range of different strains of the virus taken from all over the world and so far, no strain has been able to overcome the resistance.
The research on the so-called Turnip mosaic virus (TuMV), led by Dr John Walsh of the University of Warwick and ...
The transplant community was largely unaware of sub-standard transportation practices for donor organs until a number of fatal air crashes took the lives of transplant personnel, calling attention to procurement aviation safety. A new report highlighting the need for improved safety measures in organ procurement travel appears in the December issue of Liver Transplantation, a peer-reviewed journal published by Wiley-Blackwell on behalf of the American Association for the Study of Liver Diseases (AASLD).
In the U.S., the Organ Procurement and Transplantation Network (OPTN) ...
OAKLAND, Calif. – Compared to women never on hormone therapy, those taking hormone therapy only at midlife had a 26 percent decreased risk of dementia; while women taking HT only in late life had a 48 percent increased risk of dementia, according to Kaiser Permanente researchers.
Women taking HT at both midlife (mean age 48.7 years) and late life had a similar risk of dementia as women not on HT, according to the study which appears in the Annals of Neurology. The study was funded in part by the National Institutes of Health.
Although previous research has shown that ...
A protein known to exist in the brain for more than 30 years, called 5-lipoxygenase, has been found to play a regulatory role in the formation of the amyloid beta in the brain, the major component of plaques implicated in the development of Alzheimer's disease, according to researchers at Temple University's School of Medicine.
The researchers also found that inhibitors of this protein currently used to control asthma could possibly be used to prevent or treat Alzheimer's disease.
The researchers published their findings, "5-Lipoxygenase as Endogenous Modulator of Amyloid ...
Retinitis pigmentosa is an inherited eye disorder characterized by progressive loss of vision that in many instances leads to legal blindness at the end stage.
In a ChIP-Seq based approach, the researchers identified a key regulatory role of the transcription factor Crx (Cone-rod homeobox) in the expression of retina-specific genes and thus described an important genetic basis for visual perception. In-depth analysis of Crx mediated regulation in photoreceptors with latest technology provided by Genomatix lead then to the identification of nonsense mutations in the human ...
New stars are born in the Universe around the clock – on the Milky Way, currently about ten per year. From the birth rate in the past, we can generally calculate how populated space should actually be. But the problem is that the results of such calculations do not match our actual observations. "There should actually be a lot more stars that we can see," says Dr. Jan Pflamm-Altenburg, astrophysicist at the Argelander-Institut für Astronomie of the University of Bonn.
So, where are those stars?
For years, astronomers worldwide have been looking for a plausible explanation ...
