Search image formation for spider prey in a mud dauber wasp.

Search images are perceptual biases acquired through experience that improve an individual's ability to detect the object of their search (e.g., a predator seeking prey). In hymenopterans, examples include floral search images in bees and acquired sensory biases towards specific prey in wasp predators. Mud dauber wasps exhibit individual specialization and consistency in prey preferences through time, often based on visual and chemical cues, that may vary at intraspecific levels. However, the search image concept in wasps has not been evaluated from a visual ecology perspective. Using psychophysical visual modelling from multispectral digital photography, we measured the colour and body pattern of the spiders captured and stored in nests by the wasp Trypoxylon mexicanum. Those visual traits were compared at the community and nest cell levels, according to the nest provisioning sequence, and its relationship with spider diversity. Our results show that the wasps are choosing a small group of orb weavers (Araneidae) with similar coloration and body patterns. These findings highlight the specific visual features that may be the focal trait during search image formation in these wasps. The colour and pattern variables of spider prey were consistent over time, suggesting that individual search images may strengthen with experience.