The relationship between water quality and black fly (Diptera: Simuliidae) abundance in Tambunan District, Sabah

Black flies (Diptera : Simuliidae) have been extensively studied almost worldwide (Hamada & Grillet, 2001). This is because blackflies are among the best-known aquatic insects and globally distributed (Adler et al., 2004). Black flies in Malaysia are less known and research about this aquatic insect is still scarce especially in Borneo region. Most of the earlier studies on black flies in Sabah were related to taxonomy (Takaoka, 2001). However, studies on ecology and the role of black flies as bio-indicator has so far not been well reported yet. The aim of this study is to determine the relationship of water quality against the abundance of black flies pupa (Simuliidae). Regression test shows that relationship between dissolve oxygen (r2=0.57, p=0.02), total dissolve substance (TDS) (r2=0.18,p=0.04) and conductivity (r2=0.14, p=0.04) appeared significant to the abundance of black flies pupae. All the study sites (6 rivers) were classified into Class 1 based on Water Quality Index Classification (DOE, 2006)

Relationship between water quality & black flies (Diptera: simuliidae) abundance in Tambunan district, Sabah

A study to investigate the relationship between black flies (Simuliidae) pupa abundance and physio-chemical parameters such as velocity, water temperature, pH, dissolved oxygen, conductivity and total dissolved solid was conducted at Tambunan district, Sabah. A total of six rivers were selected as sampling stations. Five sampling points located at a distance of 5-10 meters were established in each sampling station. Sampling was conducted every fortnight for a duration of six months from October 2015 until March 2017. Samples of black flies’ larvae and pupae were manually collected from substrates consisting of grasses, plant roots and plastics which were found stuck in between the rocks with running water area. Water quality parameters that were measured during every sampling, include water temperature, velocity, pH, dissolved oxygen, conductivity and total dissolve solids (TDS). Results from this study showed that The Principal Component Analysis (PCA) revealed two PC’s which had eigenvalues >1.0 and together accounted for 78% total variability of the physio-chemical parameters. PC-1 which accounted 56% of variability defined a normal temperature (23-250C), high water velocity, high dissolved oxygen, low conductivity and low total dissolved solid. While PC-2 explained 22% of the variability was related to water pH. Pearson’s correlation result shows that only velocity had a significant relationship with the abundance of black flies (r=0.512, p<0.01), while other parameters did not show any significant relationship with its abundance. In conclusion, results from this study revealed that only water velocity had a significant relationship with the abundance of black flies

Diversity and ecology of immature black flies in streams of Tambunan, Sabah

A study on the diversity and ecology of black flies towards the rainfall variations in Sabah was conducted for 12 months from October 2015 until September 2016 at Tambunan district. The objectives of this study were, i) to determine the black flies species composition in selected streams at Tambunan., ii) to determine the relationship between seasonal changes and the abundance of black flies pupae, and iii) to determine the relationship of water quality with the abundance of black flies pupae. There were six study sites located in the Tambunan district, Sabah. The sampling point were chosen according to their accessibility for collection and the presence of water flow. The frequency of field sampling was once every fortnight. During every field sampling, black flies larvae and pupae were collected from all substrates. The physico-chemical parameter of water quality such as stream depth, width, temperature, pH, dissolved oxygen (DO), velocity, conductivity and total dissolved solids (TDS) were also measured at the time of each collection. Rainfall data information for Tambunan District was obtained from Department of Meteorology Malaysia (Sabah Branch and Batu Gajah Agriculture station, Tambunan). Results from this study recorded seven species of black flies from three sub genus: Simulium, Gomphostilbia and Nevermania. The black flies species recorded were Simulium sabahense, Simulium keningauense, Simulium beludense, Simulium parahiyangum, Simulium sheilae, Simulium sp and Simulium aureohirtum. A total of 9689 individual of black flies pupae were sampled for a period of 12 months. The Shannon Weiner diversity index (H’) ranged between 0.06 to 1.65 which indicate low diversity of black flies in all the study sites. Sg Tambunan has the highest index value with 1.65 and the lowest diversity index value was recorded at Sg Lumondou, with the value of 0.06. The common species recorded in all sites were Simulium beludense, Simulium sabahense, Simulium keningauense followed by Simulium sp. Result shows that there were no significant differences in the mean number of black flies pupae sampled between wet and dry period (Kruskal Wallis test = 5, df = 23, p=0.419). The Spearman’s rank correlation test shows that there was a weak, negative correlation between rainfall variation and the abundance of black flies pupae (rs= -0.414, p=0.044). The Principal Analysis Component (PCA) analysis results indicated two principal components that have eigenvalue >1.0 and accounted 72.67% of the total variability of ecological factors among sampling sites. PC1 includes the stream depth, width, velocity, dissolved oxygen, conductivity and total dissolve solids, while the water pH was the only parameter in PC2. Spearman’s correlation test shows that there was a significant relationship between of physico-chemical parameter such as stream depth, stream width, velocity stream temperature, DO, TDS and conductivity with the total individual of black flies pupae with p value <0.05. Thus, it can be concluded that the rainfall variations and physico-chemical parameter have a significant relationship and influenced the abundance of black flies in Tambunan