Short-term but not long-term patch avoidance in an orchid-pollinating solitary wasp

Abstract

The success of exploitative attraction of insect pollinators to rewardless flowers may depend on a constrained capacity for learning. In the case of sexually deceptive orchids, the extent to which pollinators can avoid dishonest signals through learning or adaptation is poorly known. We used field experiments with synthetic pheromone baits in concert with novel miniaturized marking techniques to investigate patterns of behavior and movement in Neozeleboria cryptoides, the wasp pollinator of the sexually deceptive orchid Chiloglottis trapeziformis. In trials of 4-and 60-min duration, visitation rates to synthetic sex pheromone declined rapidly after the first minute and remained low, suggesting short-term avoidance. Using spatially explicit capture-recapture models, we then assessed if wasps maintained this avoidance for more than 24h. Among our 4 competing behavioral models, the best supported model was one which showed an increase in detection probability at a location for wasps that had previously been caught at that location. Therefore, we found no evidence for long-term patch avoidance. If spatial learning underpins the short-term avoidance we observed, then this information appears not to be retained beyond 24h. The typical patterns of N. cryptoides movement (range = 0-161 m, median = 14.8) coupled with short-term patch avoidance likely promote outcrossing in the clonal, self-compatible orchid it pollinates.