Microenvironment drives flower visitors’ activity in a population of the bishop’s cap cactus (Astrophytum myriostigma)

Biotic and environmental conditions could affect the plant-flower visitor dynamics and, consequently, the fruit set in angiosperms. The aims of this study were: 1) to test the effect of microenvironment on activity of flower visitors in a population of Astrophytum myriostigma and 2) to describe the plant-flower visitor network’s structure. Data were recorded during two synchronous flowerings. The effect of microenvironment on flower visitors’ activity was tested through generalized linear models, and the interaction network structure was described. Frequency and duration of visits were mainly affected by atmospheric pressure and dew point. There were fewer flower visitors on plants located close to nurses and rocks. The interaction network topology tends to have a nested structure. Due to pollinators’ decline, these findings help understand the drivers limiting the flower visitors’ activity. The interactions between flower visitors and plants could be affected by atmospheric pressure alterations triggered by climate change.