A symbiotic relationship between two organisms accounts for an array of interactions that offer an even greater variety of resources such as food, shelter, protection, essential compounds, and a competitive advantage. Although the benefits of certain mutualisms may be well studied and understood, the specific chemical processes by which these organisms communicate for resources are less documented. For example, aphids form a symbiotic relationship with bacteria, Buchnera aphidicola, that live intracellularly within them in exchange for essential amino acids (Smith and Moran, 2020). The two organisms communicate through a specialized aphid cell called a bacteriocyte that the Buchnera reside in, allowing for specific transport of materials across the membrane. Eukaryotes exhibit mechanisms such as the mTOR pathway that mitigate the nutrition and cell growth factors between certain cell types, incorporating a myriad of transporters and reactions that power the basic components of a multicellular organism (James et. al, 2018). Wilson (2020) hypothesized the endosymbiosis of the pea aphid, Acyrthosiphon pisum and the bacteria living within it, Buchnera aphidicola, is regulated by the mTOR pathway. To begin to test this hypothesis, rapamycin, a known inhibitor of the mTOR pathway, was injected into aphids alongside a control treatment to observe whether or not there was an effect on aphid fecundity. After injecting aphids and counting their progeny, I found that the cumulative total of offspring in rapamycin injected aphids was significantly less than that of the controls. The mTOR pathway therefore appears to impact aphid fecundity.
