Diversity Of Spiders In Bt Cotton Field And Safety Evaluation Of Bt Proteins On Pardosa Astrigera Spider

Global farming of transgenic crops to abate insect pests of economic crops has raised queries about biosafety towards biota present in an environment.The cotton crop involves high biodiversity of insect pests along with a wide variety of their natural enemies.Use of spiders as bio control agents of insect pests,is progressively growing in sustainable crop management but very little is known about impact of GM crops on them.With an important focus concerning Bt proteins existing in GM crops,their biosafety aspect to a non-target spider,Pardosa astrigera,is an essential part of research thesis due to its role in lowering pest population within many crops.For this purpose,dietetic exposure pathways are designed to assess influence of pure Bt proteins on the spider.The way utilized during this study will not only emphasize existence of spiders in Bt cotton,in-vitro nurturing and biosafety aspect associated to GM crops but as well effects on bacterial symbionts of P.astrigera,offers awareness in an advanced way of risk valuation.In Bt cotton(L280,Cry2Ab),least abundance of spiders was in May(0.28%),highest in August(30.39%)while ahead decline noticed,reached to 12%in October.In total,27 species identified from which high abundance was of H.graminicola(68.56%)and Neoscona theisi(19.98%).Maximum inhabitants were from web entrapping spiders in field while on species level,most prevalent were from direct hunting habit.In bacterial community of spiders,composition and community structure of symbiotic microbes were fluctuating as of species.The most abundant bacterial phylum present in spiders was Proteobacteria,followed by Actinobacteria and Firmicutes and most abundant genus was Wolbachia.A specially designed hatching environment and increased space were constructed for P.astrigera to increase survival and growth of mother spiders and their progeny under controlled conditions.Highest survival(46%)was on a combination of live insects(fruit flies,pea aphids&cotton aphids)with adult aged spiders while on a liquid milk diet(milk and egg yolk),survival was 33%with 5^th instar spiderlings.Increased rearing space(plastic cups 250 m L)was associated with higher survival(66%)than rearing in 50 m L vials(38%).The Bt proteins(Cry2Aa and Cry1Fa)have not found with any deleterious effect on survival and development,days engaged in change in instar stages(from 5^th instar to adults)and on weight gain in P.astrigera,given via Bt fed early instars of bollworms larvae.Results among treatments observed with non-significant differences(p>0.05)while dinotefuran detected with its detrimental effects,at its lowest quantity(3.29 g/m L water),spiders survived only up to 5 days.In impact of Cry2Aa and Cry1Fa on symbiotic bacterial community of the spider,bacterial population remained diverse among treatments.The existence of some bacterial genera was not recorded in Bt fed adult spiders,some bacteria detected only in control spiders while some were noticed only in male or female spiders depending on treatments(Wolbachia,Clostridium sensu stricto 1,Gluconacetobacter,Glutamicibacter,Lactococcus,Aureimonas,Comamonas).At genus level,highest abundance was of Corynebacterium 1 except Bt fed females(control males 49.57%,Cry2Aa fed males 30.97%,control females 45.54%,Cry2Aa fed females7.73%;Cry1Fa fed males 32.72%,control males 49.47%,Cry1Fa fed females 13.30%,control female 45.72%).In Cry1B studies,given in the form of water along with living fruit flies as diet source after quantifying daily water intake capacity of adult spiders.The survival and weight gain in adults and 2^nd instars persisted with non-significant differences(p>0.05)among treatments while in dinotefuran treatment,survival was reached to naught percent within 5 days in adults and 2^nd instars died in 2 days.Similarly,found no effect of Cry1B on mating time between male and female spiders,egg sacs laying,egg sacs dropping and hatching of spiderlings,all studied parameters observed with non-significant differences(p>0.05)among treatments.In impact of Cry1B on symbiotic bacterial community of adult spiders,share of bacterial symbionts remained varied within treatments.Presence of bacterial genus Jeotgalicoccus was not recorded in Cry1B fed adults while Lactobacillus was not observed in Cry1B fed males.High abundance was of Corynebacterium 1except control females(Cry1B fed males 31.06%,control males 49.91%,Cry1B fed females 46.59%,control female 12.21%).In 2^nd instar spiderlings,bacterial diversity recorded with non-significant difference(p>0.05)among Cry1B fed and control.At genus level,maximum abundance was of Acinetobacter(Cry1B fed 16.29%,control 14.92%).Community structure of bacterial symbionts within Bt fed(Cry2Aa,Cry1Fa and Cry1B)spiders have affected.However,data concerning survival,development and reproductivity of the spider showed that tested Bt proteins containing GM crops,seems to be safe for the spider.Further investigations are needed to evaluate composition and functional characteristics of bacterial microbes on species level specifically with reference to Bt proteins in the spider under controlled dietic conditions.