Assessment of Iris pumila L. pollinator and florivore diversity in a common garden: a pan-trap experiment

Abstract

Nearly all botanists give pollinators credit for the remarkable diversity of flower color, shapes and sizes observed in nature. However, an increasing number of studies suggests that floral selectionis a more pluralistic process, involving not only pollinators but also herbivores and factors of the plant’s abiotic environment. To estimate Iris pumila pollinator and florivore diversity in a common garden of Institute for Biological Research in Belgrade, we used a pan trap approach. Since I. pumila displays a variety of flower color phenotypes ranging from white and yellow to various shades of purple and blue, we painted the traps in fluorescent purple, blue and yellow. A total of 391 insects were collected and identified to family or genus level. In general, insects were mostly attracted to yellow traps compared to blue and purple ones (69.3%, 19.7% and 11.0%, respectively). The most numerous potential I. pumila pollinators were bees (Anthophila) (89.8%) with predominantly genus Halictus, while sawflies (Tenthredinidae) were significantly less represented (10.2%) with only genus Athalia. As potential florivores, beetles Tropinota hirta (Scarabaeidae) and Meligethes sp. (Nitidulidae) were identified and all individuals were caught in yellow traps, while specimens of other species from Nitidulidae family were found only in the blue traps. Both pollinators and florivores showed pronounced affinity towards yellow traps, indicating that in the case of I. pumila insects have potential to be agents of floral selection. Nevertheless, it is necessary to evaluate pollinator and florivore diversity and their color preferences in I. pumila natural habitat.