Cooperation and deception in subsocial spiders

Negative frequency-
dependent selection
and gender allocation

The evolution of cooperative behavior is puzzling, especially when it is associated with costs to the altruists that are not compensated. Many theoretical models have been developed to explain why cooperation is nevertheless widespread.

One central mechanism is that cheaters or freeloaders are limited by negative frequency-dependent selection (NFDS) to a proportion where the cost to cooperators is still low. Despite the compelling logic of this concept, few studies have demonstrated NFDS experimentally.

Here, we build on previous work with the subsocial crab spider Australomisidia ergandros, where we found that some individuals in a family group hunted and shared prey (producers) from which others benefited (parasites).