Innate Adjustment of Visitation Behavior to Rewarding and Reward‐Minimized Petunia axillaris (Solanacea) Plants by Hawkmoth Manduca sexta (Sphingidae)

Plant–pollinator interactions offer an excellent system to study the stability of mutualistic interactions. While nectar production requires resources and a reduction could in principle benefit plant fitness, only few angiosperms lack nectar, and thus cheat from a pollinator's perspective. Cheating behavior may be scarce because of pollinator foraging behaviors that select for nectariferous plants. Shorter inspection duration, interaction with fewer flowers, or even complete avoidance of plants with low/no nectar may reduce the fitness of cheating plants. The effectiveness of pollinator strategies may depend on how they are implemented. Innate strategies would invariably decrease the fitness of a cheating plant, while learned responses allow cheaters to exploit naïve pollinators. Here, we studied the foraging strategies of the hawkmoth Manduca sexta during interactions with nectariferous and reward‐minimized Petunia axillaris. We found that neither naïve nor experienced hawkmoths discriminated a priori between rewarding and nectar‐less plants. However, naïve hawkmoths displayed reduced probing time per flower and number of flowers visited on reward‐minimized plants during the first trial, without showing further improved discrimination with experience. In conclusion, the foraging decision rules of hawkmoths that may reduce the fitness of reward‐minimized plants appear to be innate, with little scope for additional learning.