Fatal attraction: what is the role of visual cues in attracting prey to carnivorous plants?

Abstract

Carnivorous plants are adapted to low nutrient soils and accordingly derive nutrients by trapping animals. Despite being stationary, carnivorous plants are active predators, attracting prey through a combination of visual and olfactory cues. Through course-based undergraduate research projects, we tested the importance of visual cues in the capture of wild type and visually impaired (w1118) Drosophila melanogaster by the carnivorous plants, Drosera capensis and Nepenthes ventricosa. These studies addressed two main questions: 1) Are visual cues important for prey capture by carnivorous plants? (2) Are there differences between the wild type (Ore R) and visually impaired w1118D. melanogaster in their behavioral response to visual cues? Student groups exposed fruit flies to carnivorous plants or artificial traps within 37 L aquariums for 8-10 hours and recorded captures. They discovered that visual cues (particularly within the UV spectrum) can have a significant effect in attracting prey to specific trap types. In addition, visual acuity and irradiance levels can impact capture rates by affecting perception of visual cues. These projects illustrate a unique method for testing hypotheses about the importance of visual cues within the capture process and highlight how course-based research projects can be used to tackle relevant scientific questions.