Symbiotic relationships between animals and microorganisms are common in nature, yet the factors controlling the abundance and distributions of symbionts are mostly unknown. Aphids have an obligate association with the bacterium Buchnera aphidicola (the primary symbiont) that has been shown to contribute directly to aphid fitness. In addition, aphids sometimes harbor other vertically transmitte...

The functional response of Aphidius ervi to different Sitobion avenae densities on two wheat cultivars (Sardary and Alvand) was examined in laboratory conditions. Experiments were carried out in test tubes on an F2 lab generation without wheat clusters and also on F2 and F5 generations in pots using wheat clusters. In the tubes, female wasps were exposed to aphid densities of 2, 4, 7, 14, 28, 3...

The parasitization capacity of 3 parasitoids and the predation capacity of 3 predators towards the shallot aphid, Myzus ascalonicus Doncaster (Homoptera: Aphididae), on strawberry, Fragaria x ananassa Duchesne (Rosales: Rosaceae) cv. Honeoye, were examined in laboratory experiments. In Petri dish assays, both Aphidius colemani Viereck (Hymenoptera: Aphidiidae) and A. ervi Haliday readily stung ...