The observations on larval behavior changes found

The observations on larval behavior changes found that increased nibbling of their tails decreased feeding, leading to the accumulation of food in the tray. Low food consumption in larvae resulted in both smaller-sized larvae and prolonged stage transformation compared to the control group. Moreover, Mbare et al. (2014) reported that larvae and pupae exposed to MMF emerged to be smaller adults with lower egg-laying capacity, suggesting that MMF probably reduced their vectorial capacity.
The application of MMF on the water surface killed the aquatic stages and affected oviposition of the gravid female mosquitoes. A similar study by Bukhari and Knols (2009) found gravid female mosquitoes avoided ovipositing on an MMF-coated water surface as instinctively they do not select dirty or polluted water. As a nonionic surfactant, MMF reduced the surface tension resulting in the drowning of female Anopheles when they attempted to lay eggs on the water surface. In contrast, the MMF effect on the water surface was unlikely to have an impact on female Aedes because they lay eggs on the inner wall of the oviposition cup above the water-line (Clements, 1992). However, Okal et al. (2015) showed that a group of female mosquitoes introduced in each test cage could increase the risk of detecting pseudopreferences, especially if group sizes were small. Thus, further investigation of the oviposition preference experiments of MMF should involve a single mosquito per cage with sufficient replication.
More than 20% mortality was observed in the An. minimus control group after day 6 of the experiment. The experimental design did not allow for the water to be changed because the MMF film would have been disturbed. In order to maintain the same conditions as in the experimental groups, the current study also did not change the water in the control group and added larval food daily. These conditions resulted in the accumulation of food, the formation of Myoseverin on water surface, and then larval death.
Overall, temephos and Bti were highly effective in larval control while pyriproxyfen and MMF provided excellent control effects against the pupal stage. Temephos is an organophosphate that causes neuromuscular paralysis by inhibiting acetylcholinesterase activity in the nervous system (Fukuto, 1990). Bti is a bacterial toxin causing loss of body fluids by forming a lytic pore midgut in the larval digestive system (Lacey, 2007). The insect growth regulator, pyriproxyfen, mimics natural juvenile hormone in pupae resulting in the prevention of adult emergence (Mbare et al., 2014). The cause of pupal death was due to starvation when they failed to emerge. Therefore, larvae treated with pyriproxyfen could metamorphose to the pupal stage but then died (pupicidal activity) and hence no larvicidal effect was observed. The larvicides exhibited action after larvae had ingested or absorbed them, but MMF is a nonionic surfactant causing anoxia by water flooding in the respiratory organ of both larvae and pupae when they have contact with this agent rather than it causing mortality by ingestion (Nayar and Ali, 2003).
MMF provides high potential as a mosquito control agent against multi-stages of Ae. aegypti and An. minimus due to its ability to cause mortality in aquatic stages, inhibit larval development and deter female oviposition. MMF exhibited excellent control effects against pupae while other the larvicides produced greater larval mortality. With a high molecular weight, MMF is not expected to cross biological membranes and bioaccumulate in living organisms (Stevens, 1999). Furthermore, MMF inactivity has been reported against non-target organism (Bukhari et al., 2011). Based on the properties of polydimethylsiloxane (commonly referred to as silicone), MMF (a silicone-based product) was originally designed as an anti-evaporation liquid that can uniformly self-spread over large water surfaces without any accumulation and be resilient to wind and rain (Aquatain Products Pty. Ltd.). The self-spreading property of the MMF is useful to employ in some locations where the implementation of other control agents is difficult.