Constraints imposed by a natural landscape override offspring fitness effects to shape oviposition decisions in wild forked fungus beetles

Oviposition site decisions often maximize offspring fitness, but costs constraining choice can cause females to oviposit in poor developmental environments. It is unclear whether these constraints cumulatively outweigh offspring fitness to determine oviposition decisions in wild populations. Understanding how constraints shape oviposition in natural landscapes is a critical step toward revealing how maternal behavior influences fundamental phenomena like the evolution of specialization and the use of \"sink\" environments. Here, we applied genetic capture-recapture to reconstruct the oviposition decisions of individual females in a natural metapopulation of a beetle (Bolitotherus cornutus) that oviposits on three fungus species. We measured larval fitness-related traits (mass, development time, survival) on each fungus, and compared the oviposition preferences of females in laboratory versus field tests. Larval fitness differed substantially among fungi, and females preferred a high-quali...