The Effect Of Bacterial Endosymbionts On Predation Capacity Of Pardosa Pseudoannulata

Symbionts are widespread in organisms,and the relationship between symbionts and their hosts are interdependent and co-evolutionary.There are lots of reports on the effect of symbionts on the insecticidal microorganisms,whereas little is known on the effect of symbionts on predatory natural enemies.Spiders are important predators in rice paddy in China,symbionts including Wolbachia,Cardinium,Spiroplasma,Serratia has been found in spiders and their prey,planthoppers,whereas the roles of these symbionts has not been known.In this paper,we focus on the effect of symbionts on predation capacity of spiders,it is not only beneficial to the better understanding of the coevolutionary relationships between predators and symbionts,but also beneficial to give new insight on biological control of rice insect pests.The main results are as follows:1L The symbiont infection and vertical transmission in spiders from rice paddy in Jiangsu province,China was investigated.It was found that Pardosa pseudoannulata was the dominant species of spider in rice paddy in Jiangsu province.P.pseudoannulata collected from Danyang,Jiangsu province harbored five kinds of symbionts including Wolbachia,Cardinium,Arsenophonus,Serratia and Acinetobacter,and there was difference in infection frequencies among different symbionts.Among the above five symbionts,Serratia was the most common facultative symbiont,the infection rate was 17.71%,then Wolbachia,its infection rate was 13.54%,and the infection frequencies of Cardinium and Arsenophonus were all 2.08%,and more than 60%individuals had no symbiont The above five symbionts all could be vertically transmitted by female spiders,they also could transmitted by factors other than female spiders2.Impact of symbionts in spiders on the predation capacity:Six isofemales of P.pseudoannulata were established from spiders collected from Nanjing,Jiangsu province,the symbiont infection was different among the six isofemales.Comparison on the predation capacity of the six isofemales indicated that,symbiont infection could affect the predation capacity of spider.Isofemale N1 harboring five symbionts was not different in predation capacity with isofemale N2 only harboring Wolbachia and Serratia and isofemale N4 only harboring Acinetobacter,but the predation capacity of them was significantly lower than that of N5 which also harbored five symbionts and N3 and N6.From the above difference,it could be deduced that,Serratia might improve the predation capacity of P.pseudoannulata.3.Effect of symbionts in prey on the predation capacity of predator:Five isofemales of P.pseudoannulata were established from spiders collected from Jurong,Jiangsu province,and their predation capacity on brown planthopper(BPH)with and without Wolbachia was compared.The results showed that,2 of 5 isofemales had higher predation capacity on BPH without Wolbachia than that on BPH with Wolbachia.All the tested five isofemales of spider were infected with Serratia.The results indicated that Wolbachia in BPH affected the predation capacity of P.pseudoannulata,but there was variation among isofemales of spider.