The microbial flora of the different gut regions of the variegated grasshopper Zonocerus variegatus (L) (Orthoptera :Pyrgomorphidae)

Abstract

The microbial flora of the gut regions and gut contents of the variegated grasshopper Zonocerus variegatus instars was studied using the pour plate technique. The gut sections (Fore-, mid-, and hind-gut) harboured a variety organisms mainly bacteria, fungi and mould. Yeasts species isolated were Candida, Saccharomyces and Pichia spp. Aspergilus, Penicillium, Fusarium and Rhizopus spp. Both gram positive and gram negative bacteria were isolated. The gram negative bacteria isolated were mainly rods and members of the family Enterobacteriaceae including Proteus, Alcaligenes, Escherichia and Serratia. These species were more widely distributed in and more frequently isolated from the gut regions and their contents than the gram positive bacteria which were represented by Sreptococcus, Lactobacillus and Staphylococcus species. Gram positive bacteria were isolated from the gut extracts of the 3rd and 4th instars but were found in some of the gut regions of the 6th and adult instars. Mould population decreased gradually as the grasshopper was moulting from the 3rd to adult instars. Ranking according to microbial load was adult> 6th >4th >3rd, a reflection of their gut capacity since the microbes were part of the diet. The number and types of microbes in the gut regions of these instars are similar but significantly different in terms of total microbial load (P>=0.05). The results of this study could provide a lead into the proper understanding of the physiological processes involved in the digestion of plant materials by the insect. Keywords: Z.variegatus, microbial, bacteria, mould, yeast ,gut. (Global Journal of Pure and Applied Sciences: 2002 8(4): 447-454)