Nine facultative endosymbionts in aphids. A review

Aphids are frequently engaged in mutualistic associations with endosymbionts. Symbionts are bacterial or fungal microorganisms that can be obligate or facultative to aphids. Research showed facultative (or secondary) symbionts have numerous effects on their host aphids such as resistance to heat shock, parasitoids and fungus etc., which may consequently promote a co-evolution between symbionts and hosts. However, this symbiotic relation may be...