Influence Of Thermal Stress On Fitness And Endosymbionts Of Myzus Persicae(Hemiptera:Aphididae)in Different Body Colours

The peach potato aphid Myzus persicae(Sulzer),one of the most important agricultural pests,has several body colours between which exsist many differences.In this study,based on the amplification and analysis of bacterial 16S rRNA gene sequences,symbiotic bacteria species were indentified both in green peach aphid and red peach aphid.After heat shock,variations of symbionts varieties、mycetocyte numbers、fecundities and mortalities were investigated and performances were compared between green group and red group.The results were summarized as follows.1)Except Buchnera sp.,the primary endosymbiont,two secondary endosymbionts were indentified,which were Spiroplasma sp.and Arsenophonus sp..2)After heat shock,in both green group and red group,Arsenophonus disappeared and mycetocyte numbers firstly decreased and remain unchanged with the temperature increasing.And green group kept prevailing over red group on mycetocyte numbers.3)Mortalities of two groups kept increasing with higher temperature and longer exposed time.But red group had higher mortality at lower temperatures appearing to be more sensitive to heat stress than green group.4)Fecundity of red group was also more vulnerable to high tempeture;Fecundities of both groups played hormesis after heat shock.In sum,the result would enrich our knowledge on the symbiotic bacteria species of peach potato aphid.And confirmed that heat stress did affect on symbiotic species、mycetocyte number、fecundity and mortality of peach aphid.In this study,red peach aphid was considered more sensitive to thermal stress.However,it figured out that hormesis under heat shock could not be ignored.These results provide important information about taking advantages of thermal stress combined with symbiotic functions to control peach potato aphid in agricultural production.