Behavioral Responses of the Genus Helobdella Freshwater Leeches to the Visible Light Spectrum
Faculty Mentor Name
Ajna Rivera
Research or Creativity Area
Natural Sciences
Abstract
Freshwater leeches of the Glossiphoniidae family, genus Helobdella, were studied to determine their behavioral responses across the visible light spectrum. Previous studies have confirmed leeches in the genus Helobdella have a pair of pigmented "head" eyes that can be found in the non-segmental prostomial region of the anterior end, but have not confirmed the role they play in leech behavior, or the importance of photoreception in these leeches.
Previous research on the medicinal leech Hirudo verbana has shown that they have a complex distributed visual system including head eyes like Helobdella as well as dermal sensilla that mediate behavioral responses to green and ultraviolet (UV) light. Glossiphoniid leeches are known to rely primarily on two non-visual sensory systems for environmental interaction: a mechanosensory system that detects water movement and a chemosensory system that responds to chemical cues for locating food. Research into glossiphoniid leeches regarding their visual system and responses to light have not been conducted yet, and could help us further understand if there are more parts of their sensory system they utilize for interaction with the environment, or other behavioral responses.
To investigate whether Helobdella leeches respond to different wavelengths of light, LED light strips emitting distinct wavelengths, along with a standardized phone camera flash to maintain equal light intensity (lux) were used within environmental chambers limiting light penetration from the outside. Leech movement within these chambers was recorded and analyzed to assess behavioral responses. This experiment aims to provide insight into the light conditions that influence leech behavior, and to further our understanding of the mechanisms underlying their photoreception.
Behavioral Responses of the Genus Helobdella Freshwater Leeches to the Visible Light Spectrum
Freshwater leeches of the Glossiphoniidae family, genus Helobdella, were studied to determine their behavioral responses across the visible light spectrum. Previous studies have confirmed leeches in the genus Helobdella have a pair of pigmented "head" eyes that can be found in the non-segmental prostomial region of the anterior end, but have not confirmed the role they play in leech behavior, or the importance of photoreception in these leeches.
Previous research on the medicinal leech Hirudo verbana has shown that they have a complex distributed visual system including head eyes like Helobdella as well as dermal sensilla that mediate behavioral responses to green and ultraviolet (UV) light. Glossiphoniid leeches are known to rely primarily on two non-visual sensory systems for environmental interaction: a mechanosensory system that detects water movement and a chemosensory system that responds to chemical cues for locating food. Research into glossiphoniid leeches regarding their visual system and responses to light have not been conducted yet, and could help us further understand if there are more parts of their sensory system they utilize for interaction with the environment, or other behavioral responses.
To investigate whether Helobdella leeches respond to different wavelengths of light, LED light strips emitting distinct wavelengths, along with a standardized phone camera flash to maintain equal light intensity (lux) were used within environmental chambers limiting light penetration from the outside. Leech movement within these chambers was recorded and analyzed to assess behavioral responses. This experiment aims to provide insight into the light conditions that influence leech behavior, and to further our understanding of the mechanisms underlying their photoreception.
