S such as Vitamin D2 site growth and reproduction. Protein deficiency reduces fecundity and growth in Drosophila melanogaster [13] and in fruit-feeders protein is often limiting macronutrients [14,15,16,17,18]. In contrast diet restriction on mild starvation can increase longevity as well as tolerance to stressors such as heat 10236-47-2 biological activity stress [19,20] demonstrating the complexity of organismal nutrient acquisition and utilization. A variety of factors may affect organismal stress tolerance. These include physiological as well as behavioural changes. The bulk of studies on physiological andLarval Feeding Stress Tolerance in D. ananassaeevolutionary responses to nutrient deficiencies focus on reproduction and fecundity [12,17,21,22]. Biological stress may be defined in evolutionary terms [8]. Sibly and Calow [23] broadly 
define stress as an environmental condition that when first applied, impairs Darwinian fitness and similarly Koehn and Bayne [24] define stress as any environmental change that acts to reduce the fitness of an organism. Genetic variation in stress tolerance will result in adaptive change to an extent that depends on the frequency of environment faced by the organism and the associated physiological costs [8]. Unsuitable or insufficient food resources resulting in deprivation of normal nutrients constitutes environmental stress and it has been argued that stress associated with marginal resources impacts populations of most species [25]. Because stress resistance traits in Drosophila often vary across latitudinal clines [26], it is likely that selection affects resistance traits either directly or indirectly. Individuals within many species must survive periods of starvation or exposure to suboptimal diets. As a consequence, positive selection for resistance to starvation stress is expected in localities where food is likely to be less abundant or temporarily less reliable. When faced with nutritionally imbalanced diets, compensatory feeding for the limiting nutrients results in over ingestion of other nutrients, as is often seen when insects are confined to food low in protein relative to carbohydrate [11], this may result in increased lipid storage and reduced fitness [27,28]. Organismal stress tolerance is affected by variety of factors. Climatic changes may be met by physiological hardening processes, coma or production of metabolites making the organism tolerate temperature extremes [29,30,31]. Also an organism may compensate for nutritional stress and reduced body size by extending its growth period or altering its energy allocation to growth, hence postponing the reproductive period [32,33]. Fecundity (number of offspring produced) comprises one of the most energetically expensive processes involved in reproduction and usually is taken as a proxy value for the total reproductive efforts [34,35]. For invertebrate animals changes in fecundity due to dietary effects have been recorded for different systems and taxa including changes associated with food limitation [36,37], moisture content in the diet [38], specific nutrient deficiency [4,39], diet composition [40,41,42] and presence of inhibitory secondary metabolites [43,44]. Drosophila ananassae, a cosmopolitan and domestic species belonging to the ananassae subgroup of the melanogaster species group is stenothermic and circumtropical in distribution. India is a large tropical and subtropical continent and covers a large range of latitude and altitude. From south to north, the seasonal the.S such as growth and reproduction. Protein deficiency reduces fecundity and growth in Drosophila melanogaster [13] and in fruit-feeders protein is often limiting macronutrients [14,15,16,17,18]. In contrast diet restriction on mild starvation can increase longevity as well as tolerance to stressors such as heat stress [19,20] demonstrating the complexity of organismal nutrient acquisition and utilization. A variety of factors may affect organismal stress tolerance. These include physiological as well as behavioural changes. The bulk of studies on physiological andLarval Feeding Stress Tolerance in D. ananassaeevolutionary responses to nutrient deficiencies focus on reproduction and fecundity [12,17,21,22]. Biological stress may be defined in evolutionary terms [8]. Sibly and Calow [23] broadly define stress as an environmental condition that when first applied, impairs Darwinian fitness and similarly Koehn and Bayne [24] define stress as any environmental change that acts to reduce the fitness of an organism. Genetic variation in stress tolerance will result in adaptive change to an extent that depends on the frequency of environment faced by the organism and the associated physiological costs [8]. Unsuitable or insufficient food resources resulting in deprivation of normal nutrients constitutes environmental stress and it has been argued that stress associated with marginal resources impacts populations of most species [25]. Because stress resistance traits in Drosophila often vary across latitudinal clines [26], it is likely that selection affects resistance traits either directly or indirectly. Individuals within many species must survive periods of starvation or exposure to suboptimal diets. As a consequence, positive selection for resistance to starvation stress is expected in localities where food is likely to be less abundant or temporarily less reliable. When faced with nutritionally imbalanced diets, compensatory feeding for the limiting nutrients results in over ingestion of other nutrients, as is often seen when insects are confined to food low in protein relative to carbohydrate [11], this may result in increased lipid storage and reduced fitness [27,28]. Organismal stress tolerance is affected by variety of factors. Climatic changes may be met by physiological hardening processes, coma or production of metabolites making the organism tolerate temperature extremes [29,30,31]. Also an organism may compensate for nutritional stress and reduced body size by extending its growth period or altering its energy allocation to growth, hence postponing the reproductive period [32,33]. Fecundity (number of offspring produced) comprises one of the most energetically expensive processes involved in reproduction and usually is taken as a proxy value for the total reproductive efforts [34,35]. For invertebrate animals changes in fecundity due to dietary effects have been recorded for different systems and taxa including changes associated with food limitation [36,37], moisture content in the diet [38], specific nutrient deficiency [4,39], diet composition [40,41,42] and presence of inhibitory secondary metabolites [43,44]. Drosophila ananassae, a cosmopolitan and domestic species belonging to the ananassae subgroup of the melanogaster species group is stenothermic and circumtropical in distribution. India is a large tropical and subtropical continent and covers a large range of latitude and altitude. From south to north, the seasonal the.
