Do Locusts Understand Prime Numbers?

Dennett uses the prime-numbered life cycles of periodical cicadas to separate a functionally useful pattern from comprehension of its mathematical rationale. The ecological reasons for thirteen- and seventeen-year cycles involve competing hypotheses.

The title refers to periodical cicadas, whose familiar life cycles include thirteen and seventeen years. Mathematical features of a life cycle can be relevant to an evolutionary explanation without implying that the insect represents number theory. A functional pattern and an organism's comprehension of that pattern are separate claims.

The biology deserves more care than the memorable question suggests. Predator avoidance, predator satiation, hybridization, competition, and other factors enter competing explanations. A toy model showing an advantage for prime cycles establishes a possibility under assumptions; field evidence is needed to determine how well that account explains actual cicadas.

When to use it

Use when evaluating claims of understanding in biological or engineered systems, or when a mathematical adaptation story sounds more conclusive than the evidence warrants.

How it can help

Ask separately what pattern exists, why it may be advantageous, and whether the organism or system represents the rationale. Do not infer comprehension from successful exploitation alone.