~ 406 ~  Journal of Entomology and Zoology Studies 2016; 4(2): 406-410 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2016; 4(2): 406-410 © 2016 JEZS Received: 26-01-2016 Accepted: 27-02-2016 Shashi Meena Assistant Professor, Centre for Advanced Studies in Zoology, University of Rajasthan, Jaipur-302004, India. NP Singh Former Professor and Head, Centre for Advanced Studies in Zoology, University of Rajasthan, Jaipur-302004, India. Correspondence Shashi Meena Assistant Professor, Centre for Advanced Studies in Zoology, University of Rajasthan, Jaipur-302004, India. Effect of certain food plants on key demographic parameters of Chrotogonus trachypterus Blanchard (Orthoptera: Acrididae) Shashi Meena, NP Singh Abstract Grasshoppers are mainly polyphagous, but showed definite preferences and some degree of selectivity for certain categories of plants. There is complex interaction between properties of the food, feeding behavior, digestion and assimilation, physiology, metabolism and specific nutritional requirements of the insect. A laboratory study was conducted on effect of some selected food plants on key demographic parameters of Chrotogonus trachypterus Blanchard. Survival and longevity of nymphs as well as the reproductive performance of C. trachypterus Blanchard was greater and better, fed on cauliflower as compared to those fed only on spinach, tomato, cabbage, bajara and gram. As revealed by growth index, highest growth occurred on cauliflower (1.83 and 1.64) followed by spinach (1.31, 1.43) > tomato (1.38, 1.26) > cabbage (1.53, 1.15) > bajara (1.30, 1.27) > gram (1.26, 1.09) > wheat (1.18, 1.09) > grass (1.09, 1.02) > brinjal (0.72, 0.68) and groundnut (0.67, 0.61) in decreasing order. Keywords: Chrotogonus trachypterus Blanchard, growth index, key demographic parameters Introduction Chrotogonus trachypterus Blanchard is also known as surface grasshopper, is extremely polyphagous but shows definite preferences and some degree of selectivity for certain categories of plants. Feeding selection of acridids related to specific aspects concerning short term behavioral aspects pertaining to quantitative food intake and utilization and long term physiological effects involving growth and reproduction on diverse host plants. C. trachypterus has been found a serious pest of young seedling plants and because of greater abundance of this grasshopper in semi arid area, a laboratory study was conducted on effect of some selected food plants on its growth and development. There is complex interaction between properties of the food, feeding behavior, digestion and assimilation, physiology, metabolism and specific nutritional requirements of the insect. Key demographic parameters such as survival, fecundity, developmental rate and growth, significantly respond to changes in plant quality. Poor-quality food results in poor demographic performance and vice versa [1] . Total food availability directly affects these factors [2] . Egg production makes significant demands on the grasshopper’s nutritional economy and depends significantly on protein and energy obtained from the diet. Such results become important for understanding grasshopper population dynamics, as reproductive changes can drive population change. A polyphagous pest does not damage all the host plants with equal severity. There is considerable speculation for such selection by insects. For a better understanding of the nature of food material, it is obligatory to collect information on the rate of feeding and its effect on growth and development, the amount of food digested and the quantity of food converted into body mass [3] . The suitability of the host plant greatly depended upon the physical and chemical factors [4, 5, 6] . Few host plants provide a completely balanced diet for most grasshopper species and that grasshoppers can adjust behaviorally to optimize diets [7] . If we can learn what is required for balanced diets by economically important grasshopper species and remove that balance, then we may be able to manipulate plant communities to decrease grasshopper populations. A number of wild plants have a detrimental effect on the insect life. Such plants have great promise in crop rotation in the integrated pest management (IPM). Thus food preference studies will be of immense importance from this point of view. The purpose of this study was to determine the impact of the different food plants associated with the population of C. trachypterus in the Entomology Laboratory, Department of Zoology,