Biology subjects

Tonnang, H. E.

Publications and source records attributed to Tonnang, H. E..

3 recordsLinked to original sources

bioRxiv2024

Thermal biology of aphids and implications for agriculture and food security

Climate change poses significant challenges to agriculture and food security, particularly through its effects on insect vector populations and the pathogens they transmit. Aphids are one of the biggest group of ectotherms that transmit viruses to plants; more than 200 species have been identified as pathogen vectors. These aphids are responsible for transmitting over 300 viruses. The life-history traits of aphids such as fecundity and survival respond strongly and non-linearly to temperature and therefore to global warming. In this study, we elaborate the thermal responses for the main life-history traits (i.e, development and mortality rate) for aphid species for which data were available or generated. Also, thermal responses for virus transmission rates were elaborated to describe plant host to vector and vector to plant host dynamics. With these data, we elaborated thermal suitability models which were used to map current and projected scenarios for the transmission of viruses by aphids. Data was only available/generated for 19 aphid species, many of which only have data either at the lower or upper thermal limits. For virus transmission rates, from host plant to vector and from vector to plant data was only available/generated for potato virus Y (PVY), potato virus A (PVA), and potato leaf roll virus (PLRV) transmitted by the aphid Myzus persicae. Projections show that virus transmission by aphids will shift to northern latitudes. Understanding the thermal biology of aphids is crucial for developing effective measures to safeguard agriculture, especially staple crops, and food security in the context of climate change.

plant biology↗

bioRxiv2024

Effects of temperature on the life-history traits of Myzus persicae and its efficiency in transmitting potato virus Y (PVY) in potato crops

Aphids are highly sensitive to temperature changes and play a crucial role in transmitting plant viruses, accounting for the transmission of more than 50% of viruses that cause disease in crops. Among them, Myzus persicae is a major global pest, affecting over 400 plant species and transmitting more than 100 plant viruses, including potato virus Y (PVY), which poses a severe threat to potato crops. This study examines how temperature influences the life-history traits of M. persicae and its efficiency in transmitting PVY. Our research revealed that temperature significantly affects developmental duration, survival, and fecundity of M. persicae. The aphids exhibit the longest lifespan at 10{degrees}C and the shortest at 30{degrees}C. Similarly, fecundity declined from 29.81 offspring per female at 10{degrees}C to 14.25 at 30{degrees}C. PVY transmission efficiency was highest at 20{degrees}C. We also mapped potential PVY transmission regions and identified tropical and subtropical areas as high-risk due to their favourable temperatures and aphids abundance. Understanding these geographical variations is crucial for effective pest/disease management. Our findings emphasize the importance of integrating climatological, ecological, and epidemiological data to develop robust pest/disease management strategies to mitigate the impact of M. persicae and PVY on potato production and enhancing global food security.

plant biology↗

bioRxiv2020

Suitability of resampled multispectral datasets for mapping flowering plants in the Kenyan savannah

Pollination services and honeybee health in general are important in the African savannahs particularly to farmers who often rely on honeybee products as a supplementary source of income. Therefore, it is imperative to understand the floral cycle, abundance and spatial distribution of melliferous plants in the African savannah landscapes. Furthermore, placement of apiaries in the landscapes could benefit from information on spatiotemporal patterns of flowering plants, by optimising honeybees foraging behaviours, which could improve apiary productivity. This study sought to assess the suitability of simulated multispectral data for mapping melliferous (flowering) plants in the African savannahs. Bi-temporal AISA Eagle hyperspectral images, resampled to four sensors (i.e. WorldView-2, RapidEye, Spot-6 and Sentinel-2) spatial and spectral resolutions, and a 10-cm ultra-high spatial resolution aerial imagery coinciding with onset and peak flowering periods were used in this study. Ground reference data was collected at the time of imagery capture. The advanced machine learning random forest (RF) classifier was used to map the flowering plants at a landscape scale and a classification accuracy validated using 30% independent test samples. The results showed that 93.33%, 69.43%, 67.52% and 82.18% accuracies could be achieved using WorldView-2, RapidEye, Spot-6 and Sentinel-2 data sets respectively, at the peak flowering period. Our study provides a basis for the development of operational and cost-effective approaches for mapping flowering plants in an African semiarid agroecological landscape. Specifically, such mapping approaches are valuable in providing timely and reliable advisory tools for guiding the implementation of beekeeping systems at a landscape scale.

ecology↗