Molecular detection of establishment and geographical distribution of Brazilian isolates of Neozygites tanajoae, a fungus pathogenic to cassava green mite, in Benin (West Africa)

Article purchasedDiagnostic PCR with two specific primer pairs (NEOSSU and 8DDC) were used to monitor the establishment and geographical distribution of Brazilian isolates of Neozygites tanajoae Delalibera, Hajek and Humber (Entomophthorales: Neozygitaceae) released in Benin for the biological control of the cassava green mite, Mononychellus tanajoa (Bondar) (Acari: Tetranychidae). A total of 141 cassava fields were visited and samples of M. tanajoa suspected to be infected by N. tanajoae were collected in 60 fields distributed between the coastal Southern Forest Mosaic (SFM) and the Northern Guinea Savanna (NGS) zones of Benin, West Africa. Analysis of DNA samples of dead mites using the species specific NEOSSU primers revealed the presence of N. tanajoae in 46 fields. The second country specific pair of primers 8DDC revealed the presence of Brazilian isolates of N. tanajoae in 36 fields, representing 78.3% of fields positive for N. tanajoae. Brazilian isolates occurred from SFM to NGS zones in Benin, however, they were concentrated in fields located within former release zones (e.g. Department of Ouémé in the South and Borgou in the North). In contrast, the indigenous African isolates of N. tanajoae were evenly distributed in the sub-humid and humid savannah zones of the country. The mean infection rate of M. tanajoa with indigenous isolates of N. tanajoae was relatively low (5.3%) compared to Brazilian isolates (28%), indicating a higher biocontrol potential of the latter. This first post-release monitoring using PCR techniques showed that the Brazilian strains of N. tanajoae is well established in Benin and spread effectively in this area

Interactions between the predatory mite Typhlodromalus aripo and the entomopathogenic fungus Neozygites tanajoae and consequences for the suppression of their shared prey/host Mononychellus tanajoa

Published online: 28 October 2012The predatory mite Typhlodromalus aripo and the entomopathogenic fungus Neozygites tanajoae, both introduced from Brazil for control of the cassava green mite (CGM) Mononychellus tanajoa, now co-occur in cassava fields in Benin. However, studies on interactions between these two natural enemies and how they might affect CGM biological control are lacking. We determined in screenhouse experiments the effects of single and combined releases of N. tanajoae and T. aripo on CGM suppression. In the single natural enemy treatment, both T. aripo and N. tanajoae significantly reduced CGM densities, but the results of the predator (T. aripo) are more quickly measurable than those of the pathogen (N. tanajoae) in our short-term experiment. The level of CGM suppression in the combined natural enemy treatment was reduced considerably compared with T. aripoalone, but only slightly when compared with N. tanajoae alone, with a simultaneous reduction in T. aripo and N. tanajoae abundance or prevalence. In a laboratory experiment, T. aripo fed more on N. tanajoae-infected CGM than on healthy CGM and its oviposition and survival were reduced when fed on the former compared with the latter, which can help in explaining the reduction in numbers of T. aripo and consequently the considerable loss in suppression of CGM in the combined natural enemy treatment in the screenhouse experiment. Together, the screenhouse and the laboratory experiments predicted negative interactions between the two natural enemies with negative consequences for CGM biological control. Long-term field observations and rigorous field experiments that simultaneously manipulate T. aripo and N. tanajoae abundance and prevalence are needed to validate the prediction of this study

Age-dependent mating tactics in male bushbuck (Tragelaphus scriptus)

Intra-specific variation in mating behaviour has been described for a number of taxa including arthropods, fishes, amphibians, reptiles, birds and mammals. Several mechanisms have been proposed to explain the various mating behavioural variations observed in mammals. For example, an individual’s behaviour may be constrained by its condition or status (making-the- best of-a-bad-job strategy) or an alternative phenotype may be maintained by frequency-dependent selection influencing a genetic polymorphism (alternative strategies). In the majority of ungulates, variation in mating tactics is most likely maintained as a conditional strategy influenced by multiple internal factors like age, health or body size, as well as external factors such as population density, number of competitors and social dominance rank. In the present study, we investigated male mating tactics in a cryptic, bush-dwelling antelope from tropical Africa, the bushbuck, Tragelaphus scriptus (Figures.1, 2). Different mating strategies are expected to emerge, if variation in mating tactic is maintained as a conditional strategy influenced by age and / or body size: 1) Defending a territory when old and strong, what allows the owner to associating more frequently with females within the combined territory and home-range area. 2) No territory defence when young and weak, thereby associating with females less frequently and therefore sneak-mating with them

Late Quaternary Distribution of the Cycladophora davisiana Radiolarian Species: Reflection of Possible Ventilation of the North Pacific Intermediate Water during the Last Glacial Maximum

A comparison of micropaleontological data on the distribution of the Cycladophora davisiana radiolarian species in the surface sediment layer and the Late Quaternary sediments from the Subarctic Pacific and Far East marginal seas allowed conclusions concerning the possible conditions and occurrence of intermediate waters during the last glacial maximum. We used the modern data on the C. davisiana species, which is a micropaleontological indicator of the cold oxygen-rich upper intermediate water mass, which is now forming only in the Sea of Okhotsk. The high amount of C. davisiana in sediments of the last glacial maximum may point to the possible formation and expansion of the ventilated intermediate water in the most part of the Subarctic paleo-Pacific: the Bering Sea, the Sea of Okhotsk, within the NW Gyre, and in the Gulf of Alaska

Age and gender differences in seven tests of functional mobility

BACKGROUND: The objective of this study was to examine age and gender differences in seven tests of functional mobility. METHODS: The study included 50 young participants aged 20 to 39 years, and 684 older participants aged 75 to 98 years. Functional mobility measures included the coordinated stability test, the near tandem balance test, the six metre walk test, the sit to stand test with five repetitions, the alternate step test and the stair ascent and descent tests. RESULTS: Older participants performed significantly worse than the younger participants in all of the functional mobility tests (p < 0.001), with the older women performing worse than the older men in all of the tests (p < 0.05). Significant correlations were found within the older group among all the functional mobility tests scores (r = 0.24–0.87, p < 0.001), and between functional mobility performance and age (r = 0.14–0.35, p < 0.001). People with arthritis and stroke performed worse than people without these conditions in these tests. CONCLUSION: This study provides a normative database for performance of young and older community-dwelling people in a battery of validated and reliable functional mobility tests. The results confirm age-related differences in functional mobility between young and older adults

The Value of Mind-Body Connection in Physical Activity for Older People.

Exercise that targets balance and strength is proven to prevent falls in older age. The Successful AGEing yoga trial is the first large randomized controlled trial to assess the impact of yoga on falls in people aged ≥60 years. We conducted a realist process evaluation to explain the strong participant engagement observed using interviews (21 participants and three yoga instructors) and focus groups (12 participants and four yoga instructors). Results showed that relaxation, breathing, and yoga's mind-body connection created a satisfying internal focus on bodily sensation which was valued by participants. The mechanisms of mindfulness and embodiment appeared to facilitate this. Mindfulness and embodiment are also linked to, and enhance engagement with, other forms of physical activity. By focusing creatively on these mechanisms, we can develop a range of programs that target improvements in physical and mental health (including reducing falls and fear of falls) and appeal to older people

Female philopatry and male dispersal in a cryptic, bush-dwelling antelope: A combined molecular and behavioural approach

In most mammals, females are philopatric while males disperse in order to avoid inbreeding. We investigated social structure in a solitary ungulate, the bushbuck Tragelaphus sylvaticus in Queen Elizabeth National Park, Uganda by combining behavioural and molecular data. We correlated spatial and social vicinity of individual females with a relatedness score obtained from mitochondrial DNA analysis. Presumed clan members shared the same haplotype, showed more socio-positive interactions and had a common home range. Males had a higher haplotype diversity than females. All this suggests the presence of a matrilineal structure in the study population. Moreover, we tested natal dispersal distances between male and female yearlings and used control region sequences to confirm that females remain in their natal breeding areas whereas males disperse. In microsatellite analysis, males showed a higher genetic variability than females. The impoverished genetic variability of females at both molecular marker sets is consistent with a philopatric and matrilineal structure, while the higher degree of genetic variability of males is congruent with a higher dispersal rate expected in this sex. Evidence even for male long-distance dispersal is brought about by one male carrying a haplotype of a different subspecies, previously not described to occur in this area. © 2009 The Authors. Journal compilation. © 2009 The Zoological Society of London

Deglacial Variability in Okhotsk Sea Intermediate Water Ventilation and Biogeochemistry: Implications for North Pacific Nutrient Supply and Productivity

Highlights • Multi-proxy, multi-site reconstruction of Okhotsk Sea palaeo-productivity and mid-depth ventilation changes from 8 to 18 ka. • Link between hinterland river discharge and downstream Okhotsk Sea Intermediate Water (OSIW) ventilation/nutrient signatures. • Surplus Fe, Si(OH)4 export in OSIW during Bølling-Allerød to pelagic Pacific supported transient nutrient-replete conditions. • Subarctic and subtropical Pacific gyres disconnected during Bølling-Allerød, with restricted OSIW flow to lower latitudes. • Deglacial OSIW export and mid-depth Pacific biogeochemistry modulate millennial-scale regional CO2 source/sink conditions. The modern North Pacific plays a critical role in marine biogeochemical cycles, as an oceanic sink of CO2 and by bearing some of the most productive and least oxygenated waters of the World Ocean. The capacity to sequester CO2 is limited by efficient nutrient supply to the mixed layer, particularly from deeper water masses in the Pacific's subarctic and marginal seas. The region is in addition only weakly ventilated by North Pacific Intermediate Water (NPIW), which receives its characteristics from Okhotsk Sea Intermediate Water (OSIW). Here, we present reconstructions of intermediate water ventilation and productivity variations in the Okhotsk Sea that cover the last glacial termination between eight and 18 ka, based on a set of high-resolution sediment cores from sites directly downstream of OSIW formation. In a multi-proxy approach, we use total organic carbon (TOC), chlorin, biogenic opal, and CaCO3 concentrations as indicators for biological productivity. C/N ratios and XRF scanning-derived elemental ratios (Si/K and Fe/K), as well as chlorophycean algae counts document changes in Amur freshwater and sediment discharge that condition the OSIW. Stable carbon isotopes of epi- and shallow endobenthic foraminifera, in combination with 14C analyses of benthic and planktic foraminifera imply decreases in OSIW oxygenation during deglacial warm phases from c. 14.7 to 13 ka (Bølling-Allerød) and c. 11.4 to 9 ka (Preboreal). No concomitant decreases in Okhotsk Sea benthic-planktic ventilation ages are observed, in contrast to nearby, but southerly locations on the Japan continental margin. We attribute Okhotsk Sea mid-depth oxygenation decreases in times of enhanced organic matter supply to maxima in remineralization within OSIW, in line with multi-proxy evidence for maxima in primary productivity and supply of organic matter. Sedimentary C/N and Fe/K ratios indicate more effective entrainment of nutrients into OSIW and thus an increased nutrient load of OSIW during deglacial warm periods. Correlation of palynological and sedimentological evidence from our sites with hinterland reference records suggests that millennial-scale changes in OSIW oxygen and nutrient concentrations were largely influenced by fluvial freshwater runoff maxima from the Amur, caused by a deglacial northeastward propagation of the East Asian Summer Monsoon that increased precipitation and temperatures, in conjunction with melting of permafrost in the Amur catchment area. We suggest that OSIW ventilation minima and the high lateral supply of nutrients and organic matter during the Allerød and Preboreal are mechanistically linked to concurrent maxima in nutrient utilization and biological productivity in the subpolar Northwest Pacific. In this scenario, increased export of nutrients from the Okhotsk Sea during deglacial warm phases supported subarctic Pacific shifts from generally Fe-limiting conditions to transient nutrient-replete regimes through enhanced advection of mid-depth nutrient- and Fe-rich OSIW into the upper ocean. This mechanism may have moderated the role of the subarctic Pacific in the deglacial CO2 rise on millennial timescales by combining the upwelling of old carbon-rich waters with a transient delivery of mid-depth-derived bio-available Fe and silicate

Decadal-centennial scale monsoon variations in the Arabian Sea during the Early Holocene

An essential prerequisite for the prediction of future climate change due to anthropogenic input is an understanding of the natural processes that control Earth's climate on timescales comparable to human-lifespan. The Early Holocene period was chosen to study the natural climate variability in a warm interval when solar insolation was at its maximum. The monsoonal system of the Tropics is highly sensitive to seasonal variations in solar insolation, and consequently marine sediments from the region are a potential monitor of past climate change. Here we show that during the Early Holocene period rapid