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Was thinking about natural "zero calorie" sweetness and how these compounds could come to be via evolution. I was specifically thinking about monk fruit. While artificial selection likely played a role in the life history of the modern cultivated variety, this plant still needed to initially possess sweetness traits for humans to select. It seems to me to be an interesting case of mimicry--copy the palatability signal of caloric value of other fruits while not devoting valuable resources to creating equivalent amounts of sugars--because it depends on those other fruits/foods being consumed often enough to sustain the propagating organism. This makes it hard to classify the nature to the relationship in the propagator-mimick-mimicked triangle: the propagator-mimick relationship may be read as parasitic, commensal or mutualistic depending how we consider the value of non-caloric nutritional factors for (reproductive) success. Same can be said for the mimick-mimicked relationship, as both benefit from the strengthening of the sweetness signal, but the true signal might infact benefit more under complete knowledge on the part of the propagator. As a strategy, it is also very interesting because it requires a generalist propagator in an ecosystem with a certain amount of biodiversity, so it seems more likely for this relationship to emerge in nutrient rich environments than poorer ones.

Can anyone think of other examples and are there any existing examinations of similar relationships in the literature?

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    $\begingroup$ Nice idea. Plants generally can afford to be energetically wasteful, so I doubt we will see examples of such a high risk / low reward strategy $\endgroup$
    – KaPy3141
    Apr 9 at 5:47
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    $\begingroup$ Interesting proposition. Mogroside appears to have a very complex chemical structure which I would of thought to be very metabolically expensive to create. Although it is 250 times sweeter than sucrose is there any way to quantify if it is > 250 times less expensive to create, I am sure there are many ways to quantify metabolic expense beyond carbon to carbon comparisons etc? $\endgroup$
    – JEJS
    Apr 9 at 12:10
  • $\begingroup$ Synsepalum Dulcificum's fruit contains miraculin which makes acids taste sweet. A small amount of citric acid combined with a tiny amount of miraculin will taste like a lot of sugar. $\endgroup$ Apr 12 at 6:22
  • $\begingroup$ @KaPy3141: Proteins are expensive (nitrogen) for plants and valuable to animals. Even Drosophila can have sugar/calorie hunger and/or protein hunger. So a plant that mimics a lot of protein using a much smaller quantity of some compound (which could also be a peptide) maybe. But the main parts of the plant that are "designed" to be eaten (the fruit and nectar) aren't very proteinaceous. $\endgroup$ Apr 12 at 6:27
  • $\begingroup$ @JEJS So it could just be a energetically more expensive strategy that becomes successful in a environment where the propagator, here humans, has evolved receptiveness to sweetness. But since mogrosides can act as antioxidants, maybe the benefits outweigh the costs and the sweetness mimicry is an additional bonus? $\endgroup$ Apr 12 at 18:58

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