Nutrition is paramount for all living things and has always determined among other things the rate of population growth as well as size of individuals in the population. Studies have been done to evaluate nutritional requirements of organisms including mosquitoes. For example; in one study using Aedes aegypti, demonstrated that nutrition was paramount for larval growth, pupation and adult emergence under sterile conditions (Akov, 1962). It has also been shown that both quantitative and qualitative aspects of larval nutrition are important to mosquito development and survival (Gullan and Cranston, 1999), and also to the emergence of adults (Tun-Lin et al., 2000). Other studies have shown that food availability not only affects larval development (Yoshioka et al., 2012; Dominic and Das, 1996; Araújo et al., 2012), but also adult emergence, sexual maturation, fecundity, survival (Fellous and Lazzaro, 2010; Araújo et al., 2012), body size (Okech et al., 2007) nutrient reserves (Parker, 2005) and affects adult immunity (Grimstad and Walker, 1991). The importance of availability and quantity of food dominates the physiology of the female mosquito. It has been shown that a female mosquito does not simply choose randomly on where to lay her eggs as has been demonstrated using Culex quinquefasciatus (Chaves et al., 2009) and Aedes aegypti (Zahiri and Rau, 1998) but rather the choice of an oviposition site must demonstrate conditions more suitable to offspring development (Yoshioka et al., 2012) as well.

Important food substances necessary for optimal development of mosquitoes include carbohydrates, fats, minerals, proteins, lipids, vitamin B complex and yeast nucleic acid and these have been classified into: i) carbohydrates and its products, ii) animal proteins, iii) artificial diets, iv) yeast, v) infusions and others including guinea pig faeces etc (Asahina, 1964).

Rastrineobola argentea is a small, zooplanktivorous cyprinid fish with four rows of pharyngeal teeth (Ahnelt et al., 2006) that is not only abundant in Lake Victoria and Lake Kioga, East Africa but is also commercially valuable (Zahiri and Rau, 1998; Wanink and Witte, 2000) in East Africa. Being abundant means it is an alternative cheaper source and easily available in Kenya compared to other food substances used in mosquito culture. In addition, Rastrineobola argentea contains more than protein as a food source that influence various parameters of organism’s growth. This study was therefore undertaken to evaluate the efficacy of Rastrineobola argentea as a diet source for rearing anopheles mosquitoes in a laboratory set up.

1 Results

1.1 Effects of diet on pupae eclosion success

This experiment was conducted for twenty days. Over 90% of the pupae used in the experiment eclosed to adults (Table 1). Eclosion success did not differ significantly between early and late pupae when releases were made on damp and wet surfaces irrespective of the diet type (p > 0.05). The highest number of emerging females was recorded for Baker’s yeast for both early (69%) and (58%) and late (65%) and (61) when the pupae were released on damp and wet surfaces respectively. Less than 50% females emerged from pupae arising from larvae raised on crushed fish R. argentea and Tetramin^® Baby fish food (Figure 1).

Figure 1 Percentage number of female mosquitoes emerging per diet type per release surface

Table 1 Percentage early and late An. arabiensis pupal eclosion with respect to diet (crushed fish R. argentea, TetraminÒ Baby fish and baker’s yeast) and release surface types (damp, wet)

1.2 Effects of larval diet type on adult fecundity

Majority of the female gravid mosquitoes raised on crushed R. argentea (63%) laid eggs as compared to Tetramin^Ò Baby fish food (52%) or baker’s yeast (45%) (Table 2). Bigger egg batches were laid by mosquitoes raised on Tetramin^Ò Baby fish food (66.45 ± 5.03), as compared to crushed R. argentea (64.86 ± 4.93) or bakers’ yeast (50.49 ± 4.25). However, the number of eggs laid by the mosquitoes irrespective of the diet type did not differ significantly (p < 0.132). Gravid female mosquitoes raised on Tetramin^Ò Baby fish food were larger in size (3.06 ± 0.02 mm) as compared to those raised on crushed R. argentea (2.93 ± 0.01 mm) or baker’s yeast (3.00 ± 0.02 mm). Mosquito size significantly influenced the number of eggs laid by the female mosquitoes raised on crushed R. argentea (p < 0.001), Tetramin^Ò Baby fish food (p < 0.001) and baker’s yeast (p < 0.001). Each of the diet type given to the gravid mosquitoes significantly influenced their body size (p < 0.001) and the number of eggs laid (p < 0.013).

Table 2 Fecundity of adult An. Arabiensis mosquitoes raised on different larval diets. The percentages of ovipositing females per diet type are shown

1.3 Effect of diet type on larval turnover rate and emerged adults longevity

Larvae provided with maize pollen and crushed R. argentea pupated within 5 to 6 days (Table 3). Mosquitoes raised on crushed R. argentea lived for an average period of between 12 & 13 days, a time that was almost similar to that lived by mosquitoes raised on Tetramin^ÒBaby fish food (11 & 13 days). However, they were relatively smaller in size(3.22 ± 0.03 mm) than their counter parts raised on those raised on Tetramin^ÒBaby fish food (3.36 ± 0.03 mm).

Table 3 Mean number of days taken by the larvae to develop from first instar (L1) to pupae and adult mosquitoes to live till death

2 Discussions

Zahiri N., and Rau M.E., 1998, Oviposition attraction and repellency of Aedes aegypti (Diptera: Culicidae) to waters from conspecific larvae subjected to crowding, confinement, starvation, or infection, Journal of Medical Entomology, 35(5): 782-787