Reproductive foragers: spider males choose mates by selecting among available competitive environments

Mate choice frequently operates differently for males and females as a consequence of male competition for mates. Competitive interactions can alter the fitness payoffs of choice and the realisation of preferences under natural conditions, yet the majority of male choice studies still use binary trials that ignore social factors. Here we test the importance of contest dynamics in male choice with a large scale experiment, using a framework where females are considered analogous to foraging patches that are subject to competition. We track the mate choices and interactions of 640 spiders (Nephila plumipes) before and after manipulation of competition within enclosures, modelling the expected fitness payoffs of each male's actual choices and comparing these with all alternative choices available. We find that many males choose new females once social conditions change, and achieve higher fitness than predicted under random movement. Males increase their fitness not by moving to larger fem...