| Deceptive daisy’s ability to create fake flies explained | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9819 | | Deceptive daisy’s ability to create fake flies explained | Faculty of Science (media and communication) | <p></p><p><strong>Researchers have discovered how a South African daisy makes fake lady flies on its petals to trick male flies into pollinating it.</strong></p><p><img src="/english/PublishingImages/Lists/dualnews/My%20Items%20View/3.%20Fly%20(right)%20alongside%20fake%20lady%20fly%20(left)%20for%20comparison.%20Credit_A.Ellis.jpg" alt="3. Fly (right) alongside fake lady fly (left) for comparison. Credit_A.Ellis.jpg" class="ms-rtePosition-2" style="margin:5px;width:474px;height:255px;" />A male fly approaches a flower, lands on top of what he thinks is a female fly, and jiggles around. He's trying to mate, but it isn't quite working. He has another go. Eventually he gives up and buzzes off, unsuccessful. The plant, meanwhile, has got what it wanted: pollen.</p><p>“More than a decade ago we described how the South African daisy, <a href="https://www.journals.uchicago.edu/doi/10.1086/656487"><em>Gorteria diffusa</em></a>, uses complicated three-dimensional structures on its petals, complete with hairy bumps and white highlights, to deceive male flies. Since then we have been trying to unravel the evolutionary mechanism behind this deception," explains Prof. Allan Ellis from the Department of Botany and Zoology at Stellenbosch University and part of the team of international scientists working on this puzzle.</p><p>The results of their search was published in the journal <a href="https://www.sciencedirect.com/science/article/pii/S0960982223002701?via%3Dihub"><em>Current Biology</em></a> this week.</p><p>The researchers have identified three sets of genes involved in building the fake fly on the daisy's petals. The big surprise is that all three sets already have other functions in the plant: one moves iron around, one makes root hairs grow, and one controls when flowers are made.</p><p>The study found that the three sets of genes have been brought together in the daisy petals in a new way to build fake lady flies. The 'iron moving' genes add iron to the petal's normally reddish-purple pigments, changing the colour to a more fly-like blue-green. The root hair genes make hairs expand on the petal to give texture. And the third set of genes make the fake flies appear in apparently random positions on the petals. </p><p>“This daisy didn't evolve a new 'make a fly' gene. Instead it did something even cleverer - it brought together existing genes, which already do other things in different parts of the plant, to make a complicated spot on the petals that deceives male flies," says Prof. Beverley Glover in the University of Cambridge's Department of Plant Sciences and Director of the University's Botanic Garden, senior author of the study.<br></p><p>The researchers say the daisy's petals give it an evolutionary advantage, by attracting more male flies to pollinate it. The plants grow in a harsh desert environment in South Africa, with only a short rainy season in which to produce flowers, get pollinated, and set seed before they die. This creates intense competition to attract pollinators - and the petals with fake lady flies make the South African daisy stand out from the crowd.</p><p>Compared to most living organisms, the group of plants including the sexually deceptive daisy is very young in evolutionary terms at 1.5 to 2 million years old. The earliest daisies of this family tree didn't have the fake fly spots, which means they must have appeared on the daisy petals very rapidly.</p><p>“We'd expect that something as complex as a fake fly would take a long time to evolve, involving lots of genes and lots of mutations. But actually by bringing together three existing sets of genes it has happened much more quickly," says Dr Roman Kellenberger, a postdoctoral researcher in the University of Cambridge's Department of Plant Sciences and first author of the study.</p><p>To get their results, the researchers compared which genes were switched on in petals with, and without fake flies in the same type of daisy plant. They also compared these to petals from a different type of daisy that produces a simple spot pattern, to work out which genes were specifically involved in making the daisy's spots so deceptive.</p><p>This is the only example of a flower that produces multiple fake flies on top of its petals. Other members of the daisy family make much simpler spots – for example spots in a ring around all the petals - that aren't very convincing to real flies. By comparing the different daisies in the family tree, the researchers were able to work out the order that the fake flies came into being: colour first, then random positioning, then texture.</p><p>“It's almost like evolving a whole new organ in a very short time-frame. Male flies don't stay long on flowers with simple spots, but they're so convinced by these fake flies that they spend extra time trying to mate, and rub off more pollen onto the flower – helping to pollinate it," said Kellenberger.</p><p>This research was funded by the Swiss National Science Foundation, the Natural Environment Research Council, and the Biotechnology and Biological Sciences Research Council.<br></p><p><strong><em>Reference</em></strong></p><p><em>Kellenberger</em><em>, R. et al: '</em><em>Multiple gene co-options underlie the rapid evolution of sexually deceptive flowers in Gorteria diffusa</em><em>.'</em><em> </em><em>Current Biology, March</em><em> 2023</em>. <em>https://doi.org/10.1016/j.cub.2023.03.003</em></p><p><strong></strong></p><p><em>Image credit: Allan Ellis</em></p><p><strong>Contact details</strong></p><p>Prof. Allan Ellis, Department of Botany and Zoology, Stellenbosch University <a href="mailto:agellis@sun.ac.za">agellis@sun.ac.za</a><br></p><div>Prof. Beverley Glover, Department of Plant Sciences, University of Cambridge <a href="mailto:bjg26@cam.ac.uk">bjg26@cam.ac.uk</a><br></div><p><br></p><ul><li>The media release was issued by Cambridge University and adapted by Stellenbosch University.</li></ul><br> |
| SU improves its position on QS subject rankings | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9814 | | SU improves its position on QS subject rankings | Corporate Communication & Marketing / Korporatiewe Kommunikasie & Bemarking [Alec Basson] | <p>Stellenbosch University (SU) can count itself among the leading higher education institutions globally in the broad subject areas of Life Science and Medicine, Arts and Humanities, Social Sciences and Management, Engineering & Technology, and Natural Sciences. This is according to the <a href="https://www.topuniversities.com/subject-rankings/2023"><span class="ms-rteThemeForeColor-5-0"><strong>2023 Quacquarelli Symonds (QS) World University Rankings by Subjec</strong></span><span class="ms-rteThemeForeColor-5-0"><strong>t</strong></span></a><span class="ms-rteThemeForeColor-5-0"> </span>released on Wednesday (22 March 2023). </p><p>For the 2023 edition, 1 597 institutions were ranked across 54 subjects in the abovementioned five broad subject areas. More than 16,4 million unique papers published between 2016-2020, producing close to 117,8 million citations in 2016–2021, were analysed.<br></p><p>SU improved its standing in four of these subject areas. It achieved a top 250 spot in Life Science and Medicine and is now ranked in the top 350 in Arts and Humanities, top 450 in Engineering & Technology, top 400 in Social Sciences and Management, and top 500 in Natural Sciences.</p><p><strong>Leading in SA</strong></p><p>As far as specific subject categories are concerned, SU improved its global position in Environmental Sciences and Medicine having moved into the top 250. It is the leading university in South Africa in Agriculture & Forestry (74th in the world) and Theology, Divinity & Religious Studies, and Development Studies (both in the top 100), Chemical Engineering (top 300) and Mechanical, Aeronautical & Manufacturing Engineering (top 350). For a second year in a row, SU is ranked number one in South Africa in Agriculture & Forestry and Theology, Divinity & Religious Studies, and second in Education (top 350), Pharmacy & Pharmacology (top 300), Business & Management Studies (top 500), Psychology (top 330), Biological Sciences (top
350), and Electrical and Electronic Engineering (top 450). SU also moved into second position in English
Language & Literature (top 250) after having finished third in 2022. In Accounting & Finance, SU is among the top 330 institutions globally.<br></p><p>“In line with our vision to be Africa's leading research-intensive university, we also want to discern ourselves in higher education globally, so we are pleased that our reputation in Agriculture & Forestry and Theology, Divinity & Religious Studies has been ranked number one. As the only university in South Africa that offers viticulture and oenology due to our unique wine region, we are especially proud that Agriculture received such recognition," says Prof Hester Klopper, Deputy Vice-Chancellor for Strategy, Global and Corporate Affairs.</p><p><strong>Indicators</strong></p><p>The QS subject tables use academic reputation, employer reputation, research citations per paper, H-index and International Research Network (IRN) as indicators to rank universities. The first two of these are based on global surveys of academics and employers that are used to assess an institution's international reputation in each subject. Research citations per paper measures the average number of citations obtained per publication, and is an estimate of the impact and quality of the scientific work done by universities. The H-index assesses the stability of impact and quality of the work published by an institution's academics. The IRN is a measure of a university's efficiency in establishing stable research collaborations in each of the five broad subject areas.</p><p>Over the last few years, SU has been consistently ranked among the best tertiary institutions globally on the <a href="/english/Lists/news/DispForm.aspx?ID=9049"><strong class="ms-rteThemeForeColor-5-0">QS World University Rankings by Subject</strong></a>, the <a href="/english/Lists/news/DispForm.aspx?ID=8646"><strong class="ms-rteThemeForeColor-5-0">Times Higher Education World University Subject Rankings</strong></a>, and the<a href="/english/Lists/news/DispForm.aspx?ID=9329"> <strong class="ms-rteThemeForeColor-5-0">ShanghaiRanking's Global Ranking of Academic Subjects</strong></a>. These rankings all use different methodologies and indicators to determine universities' position on their ranking.<br></p><p><br></p> |
| World Water Day: Are there pesticides in my water? | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9812 | | World Water Day: Are there pesticides in my water? | Emma Davies & Reynold Chow | <p>World Water Day is celebrated annually on 22 March. In an opinion piece for the <em>Cape Times</em>, Master's student Emma Davies and Dr Reynold Chow from the Department of Earth Sciences emphasise the importance of monitoring our rivers for pesticides that can contaminate our water resources.<br></p><ul><li>Read the article below or click <a href="https://storage.googleapis.com/marketiq/134B0AD/MMG-1679026217353_134B3B4.pdf"><strong class="ms-rteThemeForeColor-5-0">here</strong></a><strong class="ms-rteThemeForeColor-5-0"> </strong>for the piece as published.</li></ul><p><strong>Emma Davies & Reynold Chow*</strong><br></p><p>South Africa is the leading user of pesticides in Sub-Saharan Africa, which means that our water resources are potentially at risk of being contaminated by pesticides. Pesticides are essential for large-scale crop production; however, after application they can enter surface water or groundwater where they can potentially persist and cause harm to aquatic organisms or human health. </p><p style="text-align:justify;">The theme of this year's World Water Day (22 March) is “Accelerating Change" with a focus on solving the water crisis amidst climate change. With South Africa being a drought-prone country and climate change potentially increasing the occurrence and intensity of droughts, we cannot afford to have our water resources polluted. Thus, it is key that we preserve and protect our water resources by sustainably managing activities that can affect them. To do this, we must gain a better understanding of pollutants that could contaminate our water, which includes pesticides.<br></p><p style="text-align:justify;">While there are strong regulations in place to monitor the levels of pesticide residues on produce that is exported from South Africa, we do not have regulations for restricting the levels of pesticide pollution in the environment, particularly in water. This means that our government (i.e., Department of Water and Sanitation) does not have a strategy in place to monitor our rivers for pesticides. Thus, we do not know which pesticides are persistent in the environment, and how much or how many of them are entering our waters? This can be an issue for our country's aquatic ecosystems, as well as people in rural communities that rely on surface water or groundwater. As South Africans, we will have to live with the consequences of environmental pesticide pollution, while countries that import our produce do not. <br></p><p style="text-align:justify;">The use of pesticides for agriculture is the main driver of pesticide pollution; however, non-agricultural (e.g., forestry, roadside weed control) and residential use are additional sources. It is also important to understand how these contaminants enter our ecosystem – it could be from runoff, air deposition, groundwater input, wastewater input and many others. It is essential to understand these sources and pathways because we can use this information to create compound-specific solutions, which ultimately minimizes the risks involved with pesticide use and the negative effects on communities and aquatic organisms.<br></p><p style="text-align:justify;">To help address the knowledge gaps associated with pesticide contamination, we have been monitoring for a list of 50 compounds in the Western Cape by using passive samplers. Passive samplers are small disks that are placed into rivers, where they collect pesticides via diffusion and sorption. Diffusion is when molecules move from an area of high concentration (i.e., the water) to an area of low concentration (i.e., passive sampler). Sorption is when a compound (i.e., pesticides) attaches itself to another (i.e., passive sampler) via physical or chemical processes. </p><p style="text-align:justify;">Passive sampling is useful because it is a cheap and simple alternative to other forms of environmental sampling, requiring low-cost equipment without the need of a continuous energy source (it is loadshedding-proof). Additionally, passive sampling captures pesticides over an extended period. For instance, we deploy passive samplers over a 14-day period, which allows us to calculate a 14-day average concentration of the river water. Conversely, grab sampling (i.e., taking a water sample with a bottle) only provides a single snapshot in time of the water quality. </p><p style="text-align:justify;">We deployed passive samplers in three well-known agricultural areas in Grabouw, Piketberg, and the Hex River Valley. Each catchment has a specific crop type making up most of its arable land use. For instance, the majority of Grabouw's arable land is used to grow pomme fruit, while Piketberg and the Hex River Valley are for wheat and table grapes, respectively. Looking at an area with a specific crop type helps us understand if a crop type is related to specific pesticides in the water. The samplers have been placed in rivers every month from March 2022 to March 2023. We are currently building upon a pre-existing dataset from 2017-2019. Our samples were processed and measured using instruments at Stellenbosch University's Central Analytical Facilities (SU-CAF). The methods used at SU-CAF were developed by collaborating partners from the Swiss Federal Institute of Aquatic Science and Technology (Eawag). </p><p style="text-align:justify;">Our study so far has detected 30 different pesticide compounds, with a select few showing up in high amounts. This illustrates that specific compounds are causing most of the contamination and thus should be the focus for mitigation measures. Of particular concern were two compounds, chlorpyrifos and imidacloprid, which exceeded Environmental Quality Standards (EQS). An EQS value is the minimum concentration at which the most sensitive aquatic organisms may be affected. Comparing pesticide concentrations in the water to an EQS value helps us identify which pesticides may pose a risk to aquatic life. Imidacloprid, a pesticide commonly used to treat mealy bugs in vineyards, is particularly concerning because it has exceeded its EQS value in all our samples since 2017. </p><p style="text-align:justify;">To better understand the potential environmental and human health risks of pesticide pollution, we need continuous and consistent monitoring programmes for pesticide pollution in agriculturally intensive catchment areas, combined with a recording system of the pesticides farmers use. With this information, targeted solutions can be developed which will help promote sustainable agricultural practices that will, in turn, benefit both the environment and the farmers (i.e., Integrated Pest Management). Such programmes are vital in ensuring that freshwater resources are not further polluted by pesticides, and that the health and wellbeing of communities that rely on these resources are protected.</p><p style="text-align:justify;">As we celebrate World Water Day, it is important to recognize how various types of pollution can affect our precious water resources. By gaining a comprehensive understanding of the problem, we can accelerate the development of effective solutions.</p><p style="text-align:justify;"><strong>*Emma Davies is a master's student and Dr Reynold Chow a lecturer in the </strong><strong>Department of Earth Sciences </strong><strong>at Stellenbosch University.</strong><strong> </strong><strong>Dr Chow is also affiliated with</strong><strong> </strong><strong>the</strong><strong> </strong><strong>Soil Physics and Land Management Group at the Wageningen University in The Netherlands.</strong></p><p style="text-align:justify;"> </p><p><br></p> |
| L’Oreal-UNESCO grant will support research to combat antimalarial resistance | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9788 | | L’Oreal-UNESCO grant will support research to combat antimalarial resistance | Wiida Fourie-Basson (media: Fakulteit Natuurwetenskappe) | <p>A PhD-student in chemistry at Stellenbosch University, Jessica Thibaud, is one of six South African female scientists to have received a generous grant from L'Oréal's <em>Fondation L'Oreal</em> and UNESCO (the United Nations Educational, Scientific and Cultural Organisation).<br></p><p>The <a href="https://www.unesco.org/en/prizes/women-science">L'Oréal-UNESCO For Women in Science international programme</a> provides support to female scientists at all stages in their scientific careers. According to an official media release, women still represent just 33.3% of researchers globally, and their work rarely gains the recognition it deserves.</p><p>Jessica's research focuses on identifying new chemical compounds to disrupt the life cycle of the malaria parasite <em>Plasmodium falciparum </em>after it enters the human host. It is no easy task to identify these compounds, however, as there are literally thousands/millions stored in databanks all over the world. </p><p>In 2020, malaria, a mosquito-borne parasitic disease was responsible for some 627 000 deaths worldwide, of which 96% were in Africa. The parasite is also showing increased resistance to antimalarial medication currently in use.</p><p> Jessica's research is just one aspect of a larger research focus on the design and development of antimalarial drugs, led by <a href="http://www0.sun.ac.za/chemistry/antimalarial-drug-design-and-development/">Dr Katherine de Villiers</a> in SU's Department of Chemistry and Polymer Science. Dr de Villiers' research group recently developed a two-dimensional map of antiplasmodium chemical space. Generated using a simple principal component analysis algorithm, the map visually clusters together those compounds with known antimalarial activity. For her MSc-studies under Dr de Villiers, Jessica combined this map with recently acquired skills in machine learning to identify a subset of 6 000 compounds that showed potential of targeting a specific enzyme in the parasite's life cycle. </p><p>Since beginning her PhD, Jessica has benefitted from further training provided through the <a href="https://h3dfoundation.org/about/">H3D Foundation</a> at the University of Cape Town and <a href="https://www.ersilia.io/">Ersilia</a> in the use of machine learning and Artificial Intelligence to speed up the process of discovering new drugs. Using these computational methods, she was able to narrow down the search even further to a potential 30 compounds. She is now in the process of testing these compounds in the laboratory to find the one or two with the most potential for further development. </p><p>“Apart from their anti-malarial activity, these compounds also have to show important drug-like characteristics such as solubility, selectivity, and potency before they can be considered for further development," she explains.</p><p>She plans to use the L'Oreal grant for a more powerful computer to use in the laboratory, and to attend an international congress on bioinorganic chemistry later this year. As part of the grant she also attended a week-long training programme for the 25 African L'Oreal-UNESCO laureates in the Côte d'Ivoire.<br></p><p><br></p> |
| Artificial Intelligence boost for SU research on long-Covid | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9777 | | Artificial Intelligence boost for SU research on long-Covid | Faculty of Science (Wiida Fourie-Basson) | <p>Research at Stellenbosch University (SU) into long Covid has received an “Artificial Intelligence" boost worth over R11.75 million (€600 000) over the next three years via the <a href="https://www.erasmus.ai/">Erasmus.AI search engine</a>.</p><p>The Erasmus.AI engine, lead by SU alumnus <a href="https://danielerasmus.com/">Daniel Erasmus</a>, is an immensely powerful search engine that can analyse web-scale large bodies of unstructured text – in practice over 250 000 000 URL's are processed per day and translating from fifteen different languages. This includes all open access research articles and abstracts published on <a href="https://pubmed.ncbi.nlm.nih.gov/about/">PubMed</a>.</p><p>“If you consider that nearly 5 000 medical articles are published each day, one realises there is no way that a medical specialist or researcher can remain current. We are here to give overview, enhance collaboration, in short − to change the architecture of discovery," Erasmus explains during a recent visit to SU.</p><p>The purpose of the visit was to sign a research agreement with physiologist Prof Resia Pretorius, head of the Department of Physiological Sciences and currently at the forefront of research efforts worldwide to understand <a href="https://cardiab.biomedcentral.com/articles/10.1186/s12933-021-01359-7">the role of persistent microclots</a> in the blood samples of individuals suffering from long COVID. Current thinking is that these insoluble microclots inhibit or even temporarily block blood flow in capillaries and subsequent oxygen transfer to tissue. The lack of oxygen in various parts of the body can account for many of the symptoms of long Covid. </p><p>Even more intriguing, however, is the presence of a significant number of large molecules known to significantly reduce the body's ability to regulate clot formation, trapped in these microclots, as well as a range of antibodies. In an article published in October 2022 in the journal <a href="https://pubmed.ncbi.nlm.nih.gov/36131342/">Cardiovascular Diabetology</a>, Pretorius and co-authors write that these antibodies may have significance in the immune response following acute Covid-19 illness, or driving auto-immunity in some individuals with long Covid. There is however little to no data available on these antibodies.</p><p>Pretorius and her research team have since been combing research data bases for clues to better understand the role and function of some of these antibodies.</p><p>Now, with access to the Erasmus.AI search engine and platform, they can harness the super-computing power of AI to do the searching for them, as well as visualise in one go what is out there by means of a user-friendly interface.</p><p>Pretorius is also curious to better understand the ability of enzymes such as serrapeptase and nattokinase to break down blood clots: “Currently we only have anecdotal evidence from individuals who reported improved symptoms after taking these enzymes," she explains. But maybe there is something in the literature out there that we have overlooked.</p><p>According to Erasmus, AI can provide researchers with clinical, laboratory and anecdotal reports from billions of sources out there: “AI can provide an overview where none existed. It is like a 'super Google' for professionals. Generative AI brings together the insight associated with a large-scale view, and when combined with serendipitous discovery, it most often leads to new insight and understanding," he explains.</p><p>This combination of human and artificial intelligence is what is needed to tackle the global health crisis brought on by long Covid, he adds: “The impact of long Covid is going to dwarf the pandemic phase. We need to deal with long Covid as a matter of urgency," he warns.</p><p>Erasmus, who obtained his degree in engineering at SU, is currently based in Amsterdam in The Netherlands.<br></p><p><em>On the photo above, from left to right, Prof. Louise Warnich, Daniel Erasmus, and Prof. Resia Pretorius. Photo: Ignus Dreyer</em><br></p><p><br></p> |
| Wood Science students are supporting the STEM@Maties programme | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9754 | | Wood Science students are supporting the STEM@Maties programme | Prof Martina Meincken | <p>The STEM@Maties programme is aimed at previously disadvantaged high schools to familiarise learners with experimental techniques and possible project ideas. About ten schools from the Stellenbosch / Winelands region participated.</p><p>Karl Kutzer and Keenan Nefdt from the Department of Forest and Wood Science presented various analytical techniques used to characterise the acoustical properties of wood and explained how properties, such as density, or moisture content affect sound propagation.<br></p><br> |
| Results from recent MSc study provides design values for SA Pine CLT | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9746 | | Results from recent MSc study provides design values for SA Pine CLT | Prof Brand Wessels | <p>Mr MJ Jacobs (centre) successfully defended his MSc thesis with the title 'Out-of-plane strength and stiffness prediction of SA Pine cross-laminated timber'. The most important conclusion was that the shear analogy method gave the best predictions for strength and stiffness of SA Pine cross laminated timber (CLT). A table of unfactored resistance for three-, and five-layer layups using South African strength classes was produced and structural engineers in South Africa can use that table for designing CLT buildings from SA Pine. Since submitting his thesis, MJ has worked at XLAM South Africa and has now been appointed as Director at Holzbau CPT where he was responsible for setting up a new local glulam factory. MJ is pictured here with Mr Michael Kloos (left), a structural engineer who often designs CLT buildings, and his supervisor Prof. Brand Wessels (right). The future for CLT looks bright and we wish MJ well as he embarks on his career! <br></p> |
| When climate change leaves you with the only (most expensive) option to adapt | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9739 | | When climate change leaves you with the only (most expensive) option to adapt | Wiida Fourie-Basson (Faculty of Science) | <p>There may come a time in our efforts to gradually adapt to climate change that we are pushed over a tipping point – when the only choice we face is either a completely transformed way of doing things, or nothing.<br></p><p>These so-called tipping points in adaptation are, however, going to be very capital and technology intensive, warns Prof Guy Midgley, interim director of the School for Climate Studies (SCS) at Stellenbosch University. He is the main author on a recent article, “<a href="https://stellenbosch-my.sharepoint.com/personal/science_sun_ac_za/Documents/Departemente/Botany%20and%20Zoology/Guy%20Midgley/2023_Tipping%20points/Potential%20tipping%20points%20for%20climate%20change%20adaptation%20costs">Potential tipping points for climate change adaptation costs</a>", published in the journal <em>Climate and Development</em>. The other authors are Prof Arthur Chapman, also from SCS, and Julio Araujo from SouthSouthNorth, a non-profit organisation working in the field of climate change resilience in Africa.</p><p>According to Prof Midgley there tends to be a focus on low-risk adaptation responses in the literature, mostly due to high levels of uncertainty about the impacts of climate change. </p><p>In the case of Africa, however, our adaptation capacity is already regarded as limited. In the latest Intergovernmental Panel on Climate Change (IPCC) report on Africa, breaching adaptation limits is one of the critical risks facing African countries.</p><p>In the article, they identify three phases of human adaptation to a changing climate. Firstly, in the “coping adaptation phase", the responses are inexpensive, largely reactive, and involve low-cost beneficiation of existing technologies. </p><p>Once these coping mechanisms are no longer effective, there is a transition to more deliberate efforts to find alternative technologies or practices, accompanied by an increase in costs. However, the essential characteristics of the sector are still retained.</p><p>The third phase is "strongly technology dependent and/or capital-intensive" and characterised by novel management techniques and practices that alter the essential character of the sector in question and transform it, often associated with a further steep rise in costs. </p><p><strong>What does this mean for food production and nature-based livelihoods in Africa?</strong></p><p>According to the authors, one of Africa's key vulnerabilities is the sensitivity of agricultural production to drought and heat stress, and the link between crop failures and nature-based livelihoods. </p><p>This means many communities rely on indigenous knowledge systems and local knowledge to adapt to the impacts of climate change. This is typical of the low-cost adaptation response phase. In the case of Rwanda, for example, tea production is currently limited to elevations between 1600 and 2100 metres above sea level, due to its sensitivity to heat stress.</p><p>Warming of 1 degree Celsius will shift this suitable elevation band about 160 metres higher. Tea production is also impacted by rainfall variability – less rain resulting in a smaller crop. Relying on their intimate knowledge of the area and its vegetation, local farmers can still adapt by relying on these signals.</p><p>However, as future warming and greater rainfall variability are predicted for that region, the adaptation responses become more costly, such as planting shade-providing trees and physically relocating tea plantations upslope, or using shade cloths and misting. When these do not work anymore, we enter the third and much more expensive phase, such as the physical relocation of the cropping area. </p><p>In this phase, local farmer's knowledge loses its effectiveness. </p><p>According to the authors, as indigenous knowledge systems start to fail, it will require even more costly technological solutions: “If this is the case," they write, “then African countries face a significant loss of value that is not currently considered in economic terms – the loss of generations of hard-won indigenous local knowledge".</p><p><strong>Strengthening policy making and planning in Africa</strong></p><p>Prof Midgley says they hope their identification of these tipping points in adaptation investment will help policy-makers and planners to better understand what lies ahead, as well as strengthen their stance during negotiations on the global mitigation goal.</p><p>“A focus on identifying adaptation cost tipping points would enhance the immediate value of climate impacts and adaptation research for policy makers and planners, especially in developing country regions such as Africa," they conclude. <br></p><p><em>Contact science@sun.ac.za for media interviews.</em><br></p><p>Photo: Rwandan tea plantations around Nyungwe national park. Photo credit: Ben Ayobi wikicommons - <span></span>https://commons.wikimedia.org/wiki/File:Foggy-sunrise-rwanda.ngsversion.1474048474112.adapt.1900.1.jpg<br></p> |
| Welcome to our new 1st year Forest and Wood Product Science students -2023! | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9726 | | Welcome to our new 1st year Forest and Wood Product Science students -2023! | Prof Bruce Talbot | <p>Welcome to our new 1st year Forest and Wood Product Science students -2023!<br></p> |
| New study reveals unexpected diversity of South Africa’s ecologically important long-tongued flies | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9710 | | New study reveals unexpected diversity of South Africa’s ecologically important long-tongued flies | Wiida Fourie-Basson (Faculty of Science) | <p></p><p>A detailed study of over 50 long-tongued fly species endemic to Southern Africa has shown that species known to science only account for about half of the diversity of this ecologically important pollinator group.</p><p>Southern Africa's long-tongued flies (Nemestrinidae) are unique for their exceptionally long proboscises. The most well-known is <a href="/english/Lists/news/DispForm.aspx?ID=6593"><em>Moegistorhynchus longirostris</em> </a>with a proboscis that reaches a remarkable 90 to 100mm in length – with a body length of 15 mm, the proboscis is more than five times the length of its body. These long-tongued flies are the only pollinators of many long-tubed flowers such as the critically endangered <em>Hesperantha oligantha</em>,<em> </em>endangered species such as <em>Disa scullyi</em> and the dwarf nerine (<em>Nerine humillis</em>), as well as various <em>Pelargonium</em>, <em>Plectranthus</em>, <em>Gladiolus</em>, <em>Watsonia</em> and <em>Lapeirousia</em> species. </p><p>Yet, despite being so charismatic, the family has received little taxonomic attention. The last revision of known southern African nemistrinid species was published more than 90 years ago, and included 44 named species.</p><p>In a recent paper, published in the journal <em>Invertebrate Systematics</em>, <a href="https://pollinationresearch.wordpress.com/genevieve-theron/">Dr Genevieve Theron</a> and colleagues estimates that more than half of the South African species in the Nemestrinidae family are currently undescribed. The work formed part of her doctoral research at the Centre for Functional Biodiversity at the University of KwaZulu-Natal, and included contributions from scientists at UKZN, Stellenbosch University and Rhodes University.<br></p><p><img src="/english/PublishingImages/Lists/dualnews/My%20Items%20View/edits_Genevieve%20Theron_Photocredit_Wiida%20Fourie-Basson%20(10).jpg" alt="edits_Genevieve Theron_Photocredit_Wiida Fourie-Basson (10).jpg" class="ms-rtePosition-2" style="margin:5px;width:216px;" /></p><p>Population ecologists use mark-recapture techniques to estimate the population sizes of animals like rhinos. Here, they have a known number of marked animals in a population and by using the ratio of marked to unmarked animals observed during surveys, it is possible to estimate the total population size. Dr Theron used a similar technique to estimate long-tongued fly diversity. </p><p>The research team collected 136 specimens from their known range in South Africa, Eswatini and Lesotho. Dr Theron then used DNA sequencing and morphological analysis to show that there were actually at least 58 distinct species, of which only 29 were currently recognised species. The remaining 29 could not be identified and therefore probably represent species that have not yet been described, suggesting that actual fly diversity is double the described diversity.</p><p>“We estimate that the total nemestrinid diversity in southern Africa may eventually add up to more than 80 species," she explains.</p><p>According to <a href="https://pollinationresearch.wordpress.com/dr-timo-van-der-niet/">Prof Timo van der Niet</a>, associate professor at the Centre for Functional Biodiversity at UKZN and senior author on the paper, the paper challenges the common perception among the public that most species are known to science.</p><p>“This study shows that even in a country like South Africa, with a strong tradition of natural history, much of the invertebrate diversity is likely undescribed. If this is the case for a charismatic group like long-tongued flies, it is likely even more the case for smaller insects," he warns.<br></p><p><a href="https://www.bruce-anderson-stellenbosch-university.com/">Prof Bruce Anderson</a>, an evolutionary biologist in the Department of Botany and Zoology at Stellenbosch University (SU) and co-author, says studies such as this one contribute significantly towards improved estimates of global insect diversity and are important for a better understanding of local ecology and conservation.</p><p>“We used to think that there were about 150 plant species that were completely reliant on about nine long-tongue fly species for pollination. If these flies were to disappear, many rare and endangered South African plants would probably go extinct," he explains.</p><p>But this study suggests that the ecologically important long-tongue fly species may represent more than nine distinct taxa. Furthermore, many of the undescribed fly species are likely to be involved in intricate plant interactions of their own, expanding their importance well beyond what is currently thought, he adds.</p><p>Dr Theron's task for the next three years, as a postdoctoral fellow at the KwaZulu-Natal Museum, will be to identify and describe those 29 unknown species (and many others held in collections all over the world). </p><p>The researchers hope that the findings from the study will provide a valuable basis for future conservation strategies for this important pollinator group.</p><ul><li>The paper titled “We don't know half of it: morphological and molecular evidence reveal dramatic underestimation of diversity in a key pollinator group (Nemestrinidae)" was published 5 January 2023 in the journal <a href="https://www.publish.csiro.au/IS/IS22023"><em>Invertebrate Systematics</em></a>.<br></li></ul><p>On the images above, Long-tongue flies must fully insert its proboscis into the flower to obtain a tiny droplet of nectar at the bottom of the tube. In the process pollen is placed on or removed from its head by the long-tubed iris, <em>Lapeirousia anceps</em> (on the left) and the endangered <em>Nerine humillis</em> (on the right). <em>Images: Bruce Anderson and Ethan Newman</em><br></p><p><strong>Media interviews</strong></p><p>Dr Genevieve Theron</p><p>E-mail: genevieveltheron@gmail.com</p><p>Mobile: +27 82 591 0515</p><p> </p><p>Prof Timo van der Niet</p><p>E-mail: vdniet@gmail.com</p><p>Mobile: +27 728191439</p><p> </p><p>Prof Bruce Anderson</p><p>E-mail: banderso.bruce@gmail.com</p><p>Mobile: +27 72 113 6948<br></p><p><em><br></em></p> |
