Does space matter? Estimation and evaluation of required space for commercial mass culture of grasshoppers (Acridoidea: Orthoptera).

A space-dependent mortality assay was performed on thirty-one short-horned adult grasshopper species (Acridoidea: Orthoptera) to estimate the space required for mass culture of acridids in captivity. Our findings show that acridids have a multidimensional mortality mode at different densities. The correlations between density and mortality of acridids in rearing units follow a sigmoidal curve. Acridid mortality significantly increases with individual numbers up to a threshold, after which mortality does not change even if the density increases further. A log-logistic sigmoidal function expresses the dose (density)-response (mortality) relationship in the majority of acridid species. Mortality of acridids at variable densities does not necessarily correspond with the body-mass of the insects, indicating that mortality is a body-mass independent event. As a ready reference, a utility chart has been prepared, providing the necessary conversion factor for estimating space for a given number of acridids. The present information will be helpful for commercial grasshopper farming in captivity.

Oxidative Stress-induced Toxicity and DNA Stability in Some Agri-field Based Livestock/Insect by Widely used Pesticides.

AIM AND OBJECTIVE: Humans continuously use pesticides in the field to control the pest population and weeds for considerable agricultural productivity. Side-by species like grazinganimals, insects and other species are adversely affected by or become resistant to pesticides. Insects, birds and cattle are highly abundant dwellers of the agriculture-field and represent three distinct phyla having versatile physiological features. Besides higher agricultural-productivity, protection to several species will maintain ecological/environmental balance. Studies on the effect of widely used pesticides on their DNA-stability and important enzymatic-activities are insufficient. MATERIALS AND METHODS: Antioxidant-activity (Superoxide-dismutase; SOD/Catalase- by gelzymogram- assay) and DNA-stability (fragmentation-assay) in hepatic/gut tissues were studied after in vitro exposure of Chlorpyrifos, Fenvalerate, Nimbecidine or Azadirachtin to goat/cow/poultry-hen/insect. RESULTS: In general, all pesticides were found to impair enzymatic-activities. However, lower organisms were affected more than higher vertebrates by azadirachtin-treatment. DNA fragmentation was found more in insects/poultry-birds than that of the cattle in hepatic/gut tissues. Inversely, toxicity/antioxidant marker-enzymes were more responsive in insect gut-tissues. However, mitochondrialtoxicity revealed variable effects on different species. It has been noticed that chlorpyrifos is the most toxic pesticide, followed by Fenvalerate/Nimbecidine (Azadirachtin, AZT). Nevertheless, AZT revealed its higher DNA-destabilizing effects on the field-insects as compared to the other animals. CONCLUSION: Field-insects are highly integrated into the ecosystem and the local bio-geo-chemical cycle, which may be impaired. Pesticides may have toxic effects on higher vertebrates and may sustain in the soil after being metabolized into their different derivatives. Some of the sensitive biochemical parameters of this organism may be used as a biomarker for pesticide toxicity.