A novel bee host cannot detect a microbial parasite, in contrast to its original host

Abstract

Organisms that can detect parasites may have a greater likelihood of avoiding exposure to them. We would expect hosts that share an evolutionary history with a parasite to be more likely to detect and avoid it compared to novel hosts. Nosema ceranae is a gut parasite of the Asian honey bee, Apis cerana, that has relatively recently been detected in the western honey bee, Apis mellifera. Using a Proboscis Extension Response assay, we found that A. cerana was significantly more likely than A. mellifera to avoid sucrose solutions with concentrations above 1 × 106 N. ceranae spores per mL. However, neither species avoided the sucrose solutions with lower N. ceranae concentrations, similar to those detected on flowers.