Oral Paper

         Reproductive Processes

Pollinators’ Flower Color Selection is Influenced by Sexual Dichromatism in Rare Cacti Species

Presenting Author
Scarlet Steele
Description
Pollinators’ Flower Color Selection is Influenced by Sexual Dichromatism in Rare Cacti Species Scarlet Steele, Niveditha Ramadoss, Lluvia Flores-Renteria   The reproductive success of all animal-pollinated plants depends on their ability to attract pollinators. This is especially important in dioecious species that have their sexes separate because they cannot self-fertilize. Dioecious plants usually express sexual dimorphism which is the differences in morphological characteristics between male and female individuals. Sexual dimorphism in plants’ floral traits, is a critical factor for pollinators’ attraction to those flowers. It is imperative that we further understand sexual dimorphism and its effect on pollinator visitation, which ultimately affects their reproductive success. A great model to study sexual dimorphism and its impact is Cylindropuntia wolfii, commonly known as ‘ Wolf’s cholla’. This is because this species has a functionally dioecious sexual system that possesses six different flower morphs within the same location. We have also observed the flowers to have sexually dimorphic traits that are attractive to pollinators. The goal of our current study is to determine if there is a difference in pollinator visitation rate between male and female flowers and to understand pollinator flower color choice. To achieve this we first observed whether there are any potential pollinators to the species by manual survey in the field. Then we manually observed the pollinator visitation for different male and female individuals of different flower colors by observing them for 10 mins each. Finally, to track the pollinator color preference we used the fluorescent dye that dyes the pollen and can be transported by the pollinator to other flowers.  We manually noted the presence or absence of fluorescent dye spread in the flowers of the neighboring plants. Our preliminary results showed that males attract more pollinators than females and that the pollinators are attracted to green/yellow flower colors more than orange or red. This suggests that when the pollinator density is low, the female flowers will hardly be visited leading to low seed production which has previously been reported in C. wolfii. This study has important implications for the management of rare dioecious cacti.