There is a large economic literature on the role of trust in economic prosperity. Survey reports show Nigeria is a low-trust society, but still ahead of countries like Brazil, Mexico, and Turkey.

I think you are going overboard with the folktale analysis, though. We do in fact have a folktale like this called the Frog and the Scorpion. And universally learned aphorisms (succinct folktales) exist to express every contradictory sentiment (e.g. 'the early bird catches the worm', but 'the second mouse gets the cheese'). We don't have the parable of the snake in the anus, but everybody in the high-trust Anglosphere has heard that 'no good deed goes unpunished'. No?