The Cockroach Evolved to Hate Sweets

Sugar isn't always sweet, especially when Darwin's involved. Entomologists at North Carolina State University showed that when glucose is used in roach-bait poison, cockroaches evolve to dislike sweets:

Glucose sets off bitter receptors in roach taste buds, causing roaches to avoid foods that bring on this taste-bud reaction. This aversion has a genetic basis and it eventually spreads to offspring, resulting in increasingly large groups of cockroaches that reject glucose and any baits made with it.
In normal German cockroaches, glucose elicits activity in sugar gustatory receptor neurons, which react when exposed to sugars like glucose and fructose – components of corn syrup, a common roach-bait ingredient. Generally, roaches have a sweet tooth for these sugars. [...]
Glucose-averse roaches that were forced to taste glucose refused to ingest the sugar, akin to a child who spits out her bitter-tasting food.

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