The defensive aphid symbiont Hamiltonella defensa affects host quality differently for Aphelinus glycinis versus Aphelinus atriplicis

•Facultative endosymbiotic bacteria can protect aphids from parasitoids.•Aphis craccivora and Acyrthosiphon pisum harbor Hamiltonella defensa and its bacteriophage APSE.•We tested effects of H. defensa/APSE on two aphelinid parasitoids of aphids.•H. defensa/APSE did not affect Aphelinus atriplicis parasitism but decreased adult survival on Acyrthosiphon pisum.•H. defensa/APSE increased progeny and female progeny size of Aphelinus glycinis.