Genetic population structure of the net-winged midge, Elporia barnardi (Diptera: Blephariceridae) in streams of the south-western Cape, South Africa: implications for dispersal

2002 ◽  
Vol 48 (1) ◽  
pp. 28-38 ◽  
Author(s):  
M. J. Wishart ◽  
J. M. Hughes
2009 ◽  
Vol 100 (2) ◽  
pp. 109-115 ◽  
Author(s):  
Leyla Cárdenas ◽  
Andrea X. Silva ◽  
Antonios Magoulas ◽  
Josefina Cabezas ◽  
Elie Poulin ◽  
...  

2016 ◽  
Vol 67 (8) ◽  
pp. 1103 ◽  
Author(s):  
Thomas C. Barnes ◽  
Claudia Junge ◽  
Steven A. Myers ◽  
Mathew D. Taylor ◽  
Paul J. Rogers ◽  
...  

Population structure in marine teleosts is often investigated to aid conservation and fisheries management (e.g. to assess population structure to inform restocking programs). We assessed genetic population structure of the important estuary-associated marine fish, mulloway (Argyrosomus japonicus), within Australian waters and between Australia and South Africa. Genetic variation was investigated at 13 polymorphic microsatellite markers. FST values and Bayesian estimates in STRUCTURE suggested population differentiation of mulloway within Australia and confirm strong differentiation between South Africa and Australia. The 12 Australian sample sets fell into one of four spatially separated genetic clusters. Initially, a significant signal of isolation-by-distance (IBD) was evident among Australian populations. However, further investigation by decomposed-pairwise-regression (DPR) suggested five sample sets were influenced more by genetic-drift, rather than gene-flow and drift equilibrium, as expected in strong IBD cases. Cryptic oceanographic and topographical influences may isolate mulloway populations from south-western Australia. The results demonstrate that DPR is suitable to assess population structure of coastal marine species where barriers to gene flow may be less obvious than in freshwater systems. Information on the relative strengths of gene flow and genetic drift facilitates a more comprehensive understanding of the evolutionary forces that lead to population structure, which in turn informs fisheries and assists conservation management. Large-bodied predatory scale-fish may be under increasing pressure on a global scale, owing to a variety of anthropogenic reasons. In southern Australia, the iconic sciaenid A. japonicus (mulloway, jewfish or kob) is no exception. Despite the species supporting important fisheries, much of its ecology is poorly understood. It is possible that a greater understanding of their genetic population structure can help ensure a sustainable future for the only southern Australian sciaenid.


2013 ◽  
Vol 103 (4) ◽  
pp. 473-484 ◽  
Author(s):  
Juan Antonio Sanchez ◽  
Michelangelo La-Spina ◽  
Pedro Guirao ◽  
Fernando Cánovas

AbstractDiverse agroecosystems offer phytophagous insects a wide choice of host plants. Myzus persicae is a polyphagous aphid common in moderate climates. During its life cycle it alternates between primary and secondary hosts. A spatial genetic population structure may arise due to environmental factors and reproduction modes. The aim of this work was to determine the spatial and temporal genetic population structure of M. persicae in relation to host plants and climatic conditions. For this, 923 individuals of M. persicae collected from six plant families between 2005 and 2008 in south-eastern Spain were genotyped for eight microsatellite loci. The population structure was inferred by neighbour-joining, analysis of molecular variance (AMOVA) and Bayesian analyses. Moderate polymorphism was observed for the eight loci in almost all the samples. No differences in the number of alleles were observed between primary and secondary hosts or between geographical areas. The proportion of unique genotypes found in the primary host was similar in the north (0.961 ± 0.036) and the south (0.987 ± 0.013), while in the secondary host it was higher in the north (0.801 ± 0.159) than in the south (0.318 ± 0.063). Heterozygosity excess and linkage disequilibrium suggest a high representation of obligate parthenogens in areas with warmer climate and in the secondary hosts. The FST-values pointed to no genetic differentiation of M. persicae on the different plant families. FST-values, AMOVA and Bayesian model-based cluster analyses pointed to a significant population structure that was related to primary and secondary hosts. Differences between primary and secondary hosts could be due to the overrepresentation of parthenogens on herbaceous plants.


2020 ◽  
Author(s):  
Neven Chetty ◽  
Bamise Adeleye ◽  
Abiola Olawale Ilori

BACKGROUND The impact of climate temperature on the counts (number of positive COVID-19 cases reported), recovery, and death rates of COVID-19 cases in South Africa's nine provinces was investigated. The data for confirmed cases of COVID-19 were collected for March 25 and June 30, 2020 (14 weeks) from South Africa's Government COVID-19 online resource, while the daily provincial climate temperatures were collected from the website of the South African Weather Service. Our result indicates that a higher or lower climate temperature does not prevent or delay the spread and death rates but shows significant positive impacts on the recovery rates of COVID-19 patients. Thus, it indicates that the climate temperature is unlikely to impose a strict limit on the spread of COVID-19. There is no correlation between the cases and death rates, an indicator that no particular temperature range is closely associated with a faster or slower death rate of COVID-19 patients. As evidence from our study, a warm climate temperature can only increase the recovery rate of COVID-19 patients, ultimately impacting the death and active case rates and freeing up resources quicker to enable health facilities to deal with those patients' climbing rates who need treatment. OBJECTIVE This study aims to investigate the impact of climate temperature variation on the counts, recovery, and death rates of COVID-19 cases in all South Africa's provinces. The findings were compared with those of countries with comparable climate temperature values. METHODS The data for confirmed cases of COVID-19 were collected for March 25 and June 30 (14 weeks) for South African provinces, including daily counts, death, and recovery rates. The dates were grouped into two, wherein weeks 1-5 represent the periods of total lockdown to contain the spread of COVID-19 in South Africa. Weeks 6-14 are periods where the lockdown was eased to various levels 4 and 3. The daily information of COVID-19 count, death, and recovery was obtained from South Africa's Government COVID-19 online resource (https://sacoronavirus.co.za). Daily provincial climate temperatures were collected from the website of the South African Weather Service (https://www.weathersa.co.za). The provinces of South Africa are Eastern Cape, Western Cape, Northern Cape, Limpopo, Northwest, Mpumalanga, Free State, KwaZulu-Natal, Western Cape, and Gauteng. Weekly consideration was given to the daily climate temperature (average minimum and maximum). The recorded values were considered, respectively, to be in the ratio of death-to-count (D/C) and recovery-to-count (R/C). Descriptive statistics were performed for all the data collected for this study. The analyses were performed using the Person’s bivariate correlation to analyze the association between climate temperature, death-to-count, and recovery-to-count ratios of COVID-19. RESULTS The results showed that higher climate temperatures aren't essential to avoid the COVID-19 from being spread. The present results conform to the reports that suggested that COVID-19 is unlike the seasonal flu, which does dissipate as the climate temperature rises [17]. Accordingly, the ratio of counts and death-to-count cannot be concluded to be influenced by variations in the climate temperatures within the study areas. CONCLUSIONS The study investigates the impact of climate temperature on the counts, recovery, and death rates of COVID-19 cases in all South Africa's provinces. The findings were compared with those of countries with comparable climate temperatures as South Africa. Our result indicates that a higher or lower climate temperature does not prevent or delay the spread and death rates but shows significant positive impacts on the recovery rates of COVID-19 patients. Warm climate temperatures seem not to restrict the spread of the COVID-19 as the count rate was substantial at every climate temperatures. Thus, it indicates that the climate temperature is unlikely to impose a strict limit on the spread of COVID-19. There is no correlation between the cases and death rates, an indicator that there is no particular temperature range of the climatic conditions closely associated with a faster or slower death rate of COVID-19 patients. However, other shortcomings in this study's process should not be ignored. Some other factors may have contributed to recovery rates, such as the South African government's timely intervention to announce a national lockout at the early stage of the outbreak, the availability of intensive medical care, and social distancing effects. Nevertheless, this study shows that a warm climate temperature can only help COVID-19 patients recover more quickly, thereby having huge impacts on the death and active case rates.


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