Zoology
Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/3752
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Item Seasonal forecasting of Bactrocera dorsalis Hendel, 1912 (Diptera: Tephritidae) in bioclimatic zones of Sri Lanka using the SARIMA model(CABI Agriculture and Bioscience, 2024) Wijekoon, W. M. C. D.; Ganehiarachchi, G. A. S. M.; Wegiriya, H. C. E.; Vidanage, S. P.Bactrocera dorsalis Hendel is a severe fruit pest that causes significant economic losses globally. Despite B. dorsalis having been distributed mostly across Asia, studies on its current and future density variation in Sri Lanka are sparse to date. The present study was thus carried out to assess the contemporary density variation (2020–2022) and future density fluctuation (2023–2025) of B. dorsalis in bioclimatic zones of Sri Lanka. The density was assessed using the monthly-based fruit fly trap collection method from randomly selected 40 locations in all bioclimatic zones (wet, intermediate, dry, and arid). The SARIMA modelling technique was applied for delineating the best-fit model and for density forecasting in each bioclimatic zone. The density variations were depicted for the year and for the bioclimatic zone (2020–2025) by colour intensity maps using QGIS. According to the findings, B. dorsalis shows a seasonal component to its year-round density variation and an ascending trend in its density from 2020 to 2025. Density forecasting records a 20%, 30%, 26%, and 37% density increase in the wet, intermediate, dry, and arid zones, respectively, in 2025. In 2025, the highest predicted B. dorsalis density from the arid zone and the lowest predicted density from the wet zone were recorded. This study contains the first forecasting attempt for B. dorsalis density using the SARIMA approach as well as the application of colour-intensity depiction for its density variation in Sri Lanka, which leads decision makers and stakeholders in economic agriculture to plan the scientific management of B. dorsalis to avoid its current and potential future threat to the country’s fruit industry.Item Oviposition Preference and Performance of Bactrocera dorsalis Hendel, (Diptera: Tephritidae) on Four Colour Types of Willard mango (Mangifera indica L)(Egyptian Academic Journal of Biological Sciences. A, Entomology, 2022) Wijekoon, W. M.C.D.; Ganehiarachchi, G. A.S.M.; Wegiriya, H. C. E.; idanage, S. P.Bactrocera dorsalis Hendel is the most widespread serious fruit pest in Asia and the knowledge on oviposition behaviour of B. dorsalis on different fruit varieties are vital for effective management of the pest. Hence, the present study investigated the preference and oviposition behaviour of B. dorsalis on different colour types of Willard mango variety. A series of choice and non-choice laboratory experiments for testing the oviposition preference were conducted and tested fruits were incubated until pupation and the emergence of adults. The results revealed that female B. dorsalis showed a significantly high preference to visit and oviposit in yellow colour Willard mangoes (p < /em><0.05) over red, orange and green colours. The number of pupae and number of adult flies that emerged was also significantly high in yellow colour mangoes under choice condition (p < /em><0.05). In both choice and non-choice tests, green colour Willard was less prominently used by female flies for their visiting and ovipositing (p < /em><0.05). The number of visits and visit duration of fruits was positively correlated with oviposition attempts of female flies in choice conditions. In both tests, the number of oviposition attempts was significantly correlated with the number of pupae and adults who emerged. There was no influence of the colour on the percentage of adult emergence from the pupae in non-choice trials. The study findings could be incorporated to plan and implement the control measures to avoid infestations of commercial mango varieties by fruit flies at the field and at the market level.