These same diets were used to assess the effect of larval diet on adult tracheation; "control" flies were raised and maintained in the nutritious cornmeal/agar diet with 8% yeast, whereas flies that were nutrient restricted as larvae were raised in the cornmeal/agar diet with 0.8% yeast, and then were switched to the nutritious cornmeal/agar diet with 8% yeast after eclosion.
The main ingredients – wholemeal flour, treacle and yeast – are all highly nutritious.
For the adult survival or metabolic experiments, flies of the different genotypes were reared and aged for 1 day in standard food, and were then transferred to a more defined diet with the same sugar/yeast ratio (60%/40%) but differing nutritional content: nutritious (5.4% sucrose and 3.6% yeast in 1% agar, 0.18% Nipagin), or restricted (0.9% sucrose and 0.6% yeast in 1% agar, 0.18% Nipagin).
In dietary restriction experiments, single flies reared in standard food supplemented with BPB were transferred to cuvettes containing either a nutritious diet (5.4% sucrose, 3.6% autolysed yeast flakes, 0.5% BPB, 0.18% Nipagin) or food with low nutritional value (0.9% sucrose, 0.6% autolysed yeast flakes, 0.5% BPB, 0.18% Nipagin).
Preliminary experiments with adult C. carnea showed that maize pollen (Dracma) provided together with 1 M sucrose solution resulted in similar reproduction and survival as an artificial diet consisting of sucrose, brewer's yeast and water (in proportions 7∶4∶4), which is considered as highly nutritious for adult C. carnea [49], [50].
To explain the preference of most genotypes for non-nutritious media, we hypothesized that females of these lines choose to oviposit near yeast, rather than choose to avoid yeast altogether.
Remember, heat over 50°C (122°F) kills yeast – and breads that rise slowly have a much better flavour and are more nutritious and digestible than those that rise quickly.
Yeast spores are ubiquitous in air and on the surface of grain, and they readily infect a moist, nutritious grain paste.
They are particularly nutritious.
