Title

Populations of Daphnia melanica vary in their behavioral response to visible and UV light

Presenter Information

Amanda Tompkins

Document Type

Oral Presentation

Location

SURC 137B

Start Date

16-5-2013

End Date

16-5-2013

Abstract

Daphnia are a genus of freshwater zooplankton that inhabit ponds and lakes. They are commonly used as a model organism for ecological genomics because they are easy to manipulate in the lab, can reproduce clonally, and are considered a keystone species in lake ecosystems. Daphnia melanica in high alpine lakes of the Olympic National Park are exposed to high levels of UVB. UVB rays cause DNA damage that can be detrimental to the organism if not fixed. D. melanica from more transparent ponds of the Olympic National Park have evolved faster rates of DNA repair compared to D. melanica from less transparent ponds. D. melanica can also move down the water column to avoid harmful UVB rays. Daily migration up and down the water column, known as Diel Vertical Migration, is a key aspect of Daphnia ecology and behavior. In this study, I measured vertical migration behavior of six populations of D. melanica in three different light conditions: dark, cold visible light, and UV light. Eight clones were scored for each population and four individuals were scored for each clone. All populations initially moved downwards in response to both types of light. However, the specific pattern of response differed both between light conditions and between populations. Differences in behavior between populations may reflect adaptation to different UV regimes, invertebrate predators, or distribution of food in the water column.

Faculty Mentor(s)

Alison Scoville

Additional Mentoring Department

Biological Sciences

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Populations of Daphnia melanica vary in their behavioral response to visible and UV light

SURC 137B

Daphnia are a genus of freshwater zooplankton that inhabit ponds and lakes. They are commonly used as a model organism for ecological genomics because they are easy to manipulate in the lab, can reproduce clonally, and are considered a keystone species in lake ecosystems. Daphnia melanica in high alpine lakes of the Olympic National Park are exposed to high levels of UVB. UVB rays cause DNA damage that can be detrimental to the organism if not fixed. D. melanica from more transparent ponds of the Olympic National Park have evolved faster rates of DNA repair compared to D. melanica from less transparent ponds. D. melanica can also move down the water column to avoid harmful UVB rays. Daily migration up and down the water column, known as Diel Vertical Migration, is a key aspect of Daphnia ecology and behavior. In this study, I measured vertical migration behavior of six populations of D. melanica in three different light conditions: dark, cold visible light, and UV light. Eight clones were scored for each population and four individuals were scored for each clone. All populations initially moved downwards in response to both types of light. However, the specific pattern of response differed both between light conditions and between populations. Differences in behavior between populations may reflect adaptation to different UV regimes, invertebrate predators, or distribution of food in the water column.