PARENT SESSION
Tuesday, August 8, 5:00-6:30 pm
Poster Session 8 - Aquatic ecology
Exhibit Hall, Ballroom Level, Cook Convention Center

The influences of local and regional dynamics on investment in prolonged dormancy by Daphnia.

Allen, Michael^*,1, ¹ University of Illinois at Urbana-Champaign, Urbana, IL

ABSTRACT- Variation among individuals in phenotypic traits is the raw material for individuals to adapt to spatially and temporally variable conditions. Annual organisms face unique challenges in variable environments, because they must survive through temporal and spatial catastrophes. Prolonged dormancy and dispersal are two strategies that allow these organisms to deal with variability and persist in metapopulations through time. Zooplankton are one group that employ these strategies to survive variable conditions. Here, I explore dispersal and prolonged dormancy in zooplankton communities that are subject to varying levels of human-mediated habitat fragmentation. Previous work suggests zooplankton dispersal is frequent, but the scale of dispersal is limited, implying important effects of isolation on dispersal limitation. Currently, I am documenting dormancy patterns in Daphnia across a range of environmental conditions through intensive field surveys of ponds, reciprocal transplants of diapausing eggs, and a regional survey of Daphnia hatching fractions. Results thus far show that the abundance of Daphnia and the maximum sex ratio vary greatly during peak ephippial production within ponds surveyed (range: 10⁰ – 10² ind./L and 0.1 – 17.0 %, respectively). This work is providing the first estimates of regional variability in and genetic control of diapause among temporary pond Daphnia. Together, these studies will improve our understanding of the effects of local and regional processes on life history variability in zooplankton. –

Key words: Aquatic Ecology, Daphnia