Life Science Journal 2014;11(7) http://www.lifesciencesite.com 152 Developmental instability in Odonata larvae in relation to water quality of Serdang River, Kedah, Malaysia Salman A. Al-Shami 1,2 *, Siti Nurhanani Hishamuddin 1 , Che Salmah Md Rawi 1 , Nur Huda Abdul 1, Abu Hassan Ahmad 1 1 School of Biological Sciences, Universiti Sains Malaysia, Penang 11800, Malaysia 2 Biology Department, Faculty of Science, University of Tabuk, P.O. Box 1458, Tabuk 7134, Saudi Arabia. Email: alshami200@gmail.com Abstract: We examined the fluctuating asymmetry (FA) in larvae of two Odonata genera; Pseudagrion sp. (Zygoptera: Coenagrionidae) and Onychothemis sp. (Anisoptera: Libelulidae) living in a relatively polluted river as a tool for water quality assessment. Larval and water samples were collected monthly from January to June 2008. Various water parameters including pH, temperature, velocity, nitrate, phosphate, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), and ammonium-N content were recorded. Composite effect of selected water parameters expressed as Water Quality Index (WQI) was also calculated. FA indices [(FA), absolute asymmetry (AbsFA), composite fluctuating asymmetry (CFA)] of the first and second antennal segments of Onychothemis sp. and and last tarsal segment of Pseudagrion sp. hind legs were calculated. We found that high FA levels in the selected traits for the two Odonata species were associated with deterioration in the water quality (WQI). BOD and pH were positively correlated with high FA indices in the antennal segments of Onychothemis sp. The FA levels calculated as FA indices of last tarsal segment of Pseudagrion sp. hind legs were positively correlated with ammonium-N, phosphate, and COD. We concluded that selected traits of the odonate taxa are useful bioindicators as the incidence of fluctuating asymmetry in their larvae was strongly associated with deterioration in the water quality of the river. [Al-Shami S., Siti Nurhanani H., Che Salmah M. R., Salman A., Nur Huda A., Abu Hassan A. Developmental instability in Odonata larvae in relation to water quality of Serdang River, Kedah, Malaysia. Life Sci J 2014;11(7):152-159]. (ISSN:1097-8135). http://www.lifesciencesite.com . 19 Keywords: Odonata; Malaysia; fluctuating asymmetry; water quality. 1. Introduction Developmental instability in the final morphology of organisms has been highlighted as a reliable indicator for environmental quality. Changes in the morphology of individuals including deformities, phenodeviations, and asymmetries have been included in recent environmental assessment studies in aquatic (Almeida et al. 2008; Al-Shami et al. 2010a, b; Al-Shami et al. 2011a, b; Arambourou et al. 2012) and terrestrial ecosystems (Pinto et al. 2012). The final morphology characteristics of an organism are a result of delicate balance of various physiological, biochemical, genetics and environmental processes which may interfere during any stage of individual development and growth (Clarke 1993; Servia et al. 2004; Al-Shami et al. 2011a, b). Thus, developmental stability of any organism is indicated by its capability to maintain a normal shape under effects of certain conditions (Kozlov et al. 2002). Therefore, any deviation in the shape and/or size of any morphological traits is considered to be disruption in the developmental mechanisms due to genetic (Clarke 1993) or environmental factors (Al-Shami et al. 2011a). Fluctuating asymmetry (FA) a common tool applied for measuring the developmental instability (Clarke 1993). According to Palmer (1994), FA is defined as the random deviation from typical symmetry of any bilateral anatomical character. Hence, FA always presents a normal distribution around the mean of zero (Palmer 1994). These departures apparently occur on the left or right side of an organism under stresses of environmental or genetic conditions which disrupt the proper development (Parson 1990). Consequently, FA may offer an early warning tool to determine the effects of environmental stresses on organisms prior to critical changes in the population and community structures (Clarke 1993). Evidently, the association between occurrence of morphological and developmental instability and environmental quality has been addressed in aquatic ecosystems by using aquatic insects (chironomids: Al- Shami et al. 2010a; Al-Shami et al. 2011a, b; Arambourou et al. 2012; mayflies: Dobrin and Corkum1999; dragonflies: Carchini et al. 2000; Chang et al. 2007a, b) and fish (Almeida et al. 2008) as models. Contamination with pesticides was suggested to be the most influential factor to cause FA in aquatic organisms. For example, Valentine and Soule (1973) had shown increasing FA of fin rays in grunion fry, a marine fish, exposed to increasing levels of p,p’-DDT in the laboratory. Similarly, Dobrin and Corkum