Dietary and body mass thresholds for reproduction in grasshoppers

An organism’s dietary protein should match its respective dietary needs to yield the most advantageous effects; an extended lifespan and increased reproductive output. The key challenge however, is how to tailor a specific diet to an organism’s individual needs. Applying the technique of Piper et. al, we can approximate the optimal diet of the lubber grasshopper, Romalea microptera, by using the AA profile of vitellogenin (Vg), the precursor to egg yolk protein. The lubber grasshopper, Romalea microptera, was selected because of its plasticity in reproductive responsiveness in response to diet quality and quantity. Each of the organisms were fed 1g of romaine lettuce, ad libitum (ad-lib) zero protein high carbohydrate artificial diet and a different experimentally manipulated diet. The 4 treatment groups, Vg-balanced AA, unbalanced AA, ad-lib lettuce, and dietary restriction (DR), dietary treatments were applied twice daily from day 2 of adulthood to egg laying. The experimental group was force-fed the balanced AA diet, which was derived from the AA composition of vitellogenin. The unbalanced AA group was fed an isonitrogenous diet with over representations of AA’s found in romaine. The ad lib group had unlimited access to romaine and was force-fed PBS. The DR group was fed a diet comprising of 1 gram of romaine and PBS. The results indicated ad-lib group had the highest yield, followed by Vg-balanced, unbalanced, and DR . In contrast, somatic mass and storage did not differ across 3 groups fed 1gm lettuce daily. Isonitrogenous diets exhibited difference in reproduction but not somatic growth