Performance of the African edible bush-cricket,Ruspolia differens,on single and mixed diets containing inflorescences of their host plant species

摘要

The African edible bush-cricket,Ruspolia differens(Serville) (Orthoptera: Tettigoniidae), is an economically valuable insect in sub-Saharan Africa. For its mass-rearing, suitable diets that can sustain its performance need to be identified. This study aimed at finding inflorescence diets of 10 host plant species and their mixtures that result in the highestR. differensproduction. We reared newly hatched nymphs to adults on inflorescences of single host species, and also on a gradient of five diversifying dietary mixtures consisting of one and mixtures of two, three, five, and seven host plant species. For the single host-plant diets, the developmental time was shortest onPennisetum purpureum,Chloris gayana, andBrachiaria ruziziensis(approximately 63 days), whereas the fresh weight was highest onB. ruziziensisandP. purpureum(approximately 0.383 g). Survival was highest (>65%) onC. gayana,P. purpureum,B. ruziziensis,Setaria sphacelata, andSporobolus pyramidalis, and lowest onPanicum maximum,Hyparrhenia rufa,Cynodon dactylon, andPaspalum scrobiculatum(<40%). With respect to diet mixtures, the developmental time was significantly shorter (on average 16 days shorter), and survival was higher, in the most diversified diets compared to the least diversified diets. The contents of polyunsaturated fatty acids and fatty acid composition did not differ significantly among the diets. However, the content of monounsaturated fatty acids differed significantly among the diets and there was a significant diet*sex interaction. From the applied point of view, based on our results, for maximal weight and survival plus fast development, we recommend rearing onP. purpureum,C. gayana,B. ruziziensis, andS. sphacelata, and on dietary mixtures of inflorescences. These findings are important in designing large-scale rearing programs for this species.