The effects of progressive land use changes on the distribution, abundance and behavior of vector mosquitoes in Sabah, Malaysia

• Main Author: Evyen Wevan Jebrail
• Format: Thesis
• Language: English; English
• Published: 2020
• Subjects: QL461-599.82 Insects
• Online Access: https://eprints.ums.edu.my/id/eprint/42312/1/ABSTRACT.pdf; https://eprints.ums.edu.my/id/eprint/42312/2/FULLTEXT.pdf; https://eprints.ums.edu.my/id/eprint/42312/

Land use changes as a result of infrastructural and agricultural development may affect the ecological balance of many organisms. Mosquitoes are amongst the most sensitive to environmental changes since their diversity, distribution and abundance are influenced by even small changes in the environmental conditions such as the availability of suitable breeding sites. This research was conducted to study the effects of progressive land use changes on the occurrence of vector mosquitoes, to determine the status of anopheline mosquitoes as a vector in changing land uses and also to study the seasonality, abundance and behavior of vector mosquitoes in study areas. Field collections and observations were conducted in three different sites of varying disturbance levels at the Stability of Altered Forest Ecosystem (SAFE) Project experimental areas in Kalabakan i.e., old growth forest (OG) which is located in Maliau Basin Conservation Area (MBCA), logged forest (LFE) and Block B (heavily logged forest with 50% forest coverage). For every sampling, two collectors spent two nights at each study site and performed the human landing catches (HLC) technique to collect mosquitoes. HLC was carried out between 18:00 hr to 00:00 hr in each sampling. All anopheline mosquitoes were dissected the next morning for sporozoites inspection. Meteorological data was recorded on hourly basis during mosquito samplings. A standard dipper was used for larvae collection in all potential breeding sites such as ground pools and streams. A total of 1032 individuals representing five genera of mosquitoes were collected. Anopheles ba/abacensiswas the most dominant species with 519 individuals managed to be collected. An. balabacensis was the predominant species in OG and Block B with 280 and 165 numbers of individuals respectively. Meanwhile in LFE, the most dominant species was Aedes a/bopictus with 474 individuals collected. There was a significant difference between the mosquito abundance in all study area (P= 0.029). A total of 420 larvae collected categorized as Cu/ex (62.62%), Aedes (32.86%), Anopheles (2.38%) and Armigeres (2.14%). 360 out of 519 anopheline mosquitoes had been dissected and the results showed that none of them were found positive for Plasmodium infection. Pearson's Correlation analysis was used to assess the relationship between meteorological data and mosquito density at different study areas and the results showed that the presence of mosquito was not influenced by environmental factor such as temperature, humidity, atmospheric pressure and wind speed. This study strongly suggests that land use changes do affect mosquito diversity and abundance by altering, creating or providing places for the adult mosquitoes to breed.