Costs and benefits of a superinfection of facultative symbionts in aphids.

摘要: Symbiotic associations between animals and inherited micro-organisms are widespread in nature. In many cases, hosts may be superinfected with multiple symbionts. Acyrthosiphon pisum (the pea aphid) harbour more than one facultative symbiont (called secondary symbionts) addition to the obligate primary symbiont, Buchnera aphidicola. Previously we demonstrated that, a controlled genetic background, A. infected either Serratia symbiotica or Hamiltonella defensa R- T-type that study) were resistant attack by parasitoid Aphidius ervi. Here, examined consequences of both resistance-conferring We found an line co-infected S. H. symbionts exhibits even greater resistance parasitism ervi singly lines. Despite this added benefit resistance, superinfections appeared rare our survey Utah symbionts, which is probably attributable severe fecundity costs. Quantitative polymerase chain reaction estimates indicate while density similar hosts, densities increased dramatically hosts. Over-proliferation antagonistic interactions harmful aphid host. Our results host-symbiont interactions, among themselves play critical role determining distributions natural populations.